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Cat - Domestic Cat - House Cat (Felis Catus) by millicand@rocketmail.com

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Cat - Domestic Cat - House Cat (Felis Catus)

The cat (Felis catus), commonly referred to as the domestic cat or house cat, is the only domesticated species in the family Felidae. Recent advances in archaeology and genetics have shown that the domestication of the cat occurred in the Near East around 7500 BC. It is commonly kept as a house pet and farm cat, but also ranges freely as a feral cat avoiding human contact. It is valued by humans for companionship and its ability to kill vermin. Because of its retractable claws it is adapted to killing small prey like mice and rats. It has a strong flexible body, quick reflexes, sharp teeth, and its night vision and sense of smell are well developed. It is a social species, but a solitary hunter and a crepuscular predator. Cat communication includes vocalizations like meowing, purring, trilling, hissing, growling, and grunting as well as cat body language. It can hear sounds too faint or too high in frequency for human ears, such as those made by small mammals. It also secretes and perceives pheromones.

Female domestic cats can have kittens from spring to late autumn in temperate zones and throughout the year in equatorial regions, with litter sizes often ranging from two to five kittens. Domestic cats are bred and shown at events as registered pedigreed cats, a hobby known as cat fancy. Animal population control of cats may be achieved by spaying and neutering, but their proliferation and the abandonment of pets has resulted in large numbers of feral cats worldwide, contributing to the extinction of bird, mammal and reptile species.

As of 2017, the domestic cat was the second most popular pet in the United States, with 95.6 million cats owned and around 42 million households owning at least one cat. In the United Kingdom, 26% of adults have a cat, with an estimated population of 10.9 million pet cats as of 2020. As of 2021, there were an estimated 220 million owned and 480 million stray cats in the world.

Etymology and naming
The origin of the English word cat, Old English catt, is thought to be the Late Latin word cattus, which was first used at the beginning of the 6th century. The Late Latin word may be derived from an unidentified African language. The Nubian word kaddîska 'wildcat' and Nobiin kadīs are possible sources or cognates. The Nubian word may be a loan from Arabic قَطّ‎ qaṭṭ ~ قِطّ qiṭṭ.

The forms might also have derived from an ancient Germanic word that was imported into Latin and then into Greek, Syriac, and Arabic. The word may be derived from Germanic and Northern European languages, and ultimately be borrowed from Uralic, cf. Northern Sámi gáđfi, 'female stoat', and Hungarian hölgy, 'lady, female stoat'; from Proto-Uralic *käďwä, 'female (of a furred animal)'.

The English puss, extended as pussy and pussycat, is attested from the 16th century and may have been introduced from Dutch poes or from Low German puuskatte, related to Swedish kattepus, or Norwegian pus, pusekatt. Similar forms exist in Lithuanian puižė and Irish puisín or puiscín. The etymology of this word is unknown, but it may have arisen from a sound used to attract a cat.

A male cat is called a tom or tomcat (or a gib, if neutered). A female is called a queen or a molly, if spayed, especially in a cat-breeding context. A juvenile cat is referred to as a kitten. In Early Modern English, the word kitten was interchangeable with the now-obsolete word catling.

A group of cats can be referred to as a clowder or a glaring.

Taxonomy
The scientific name Felis catus was proposed by Carl Linnaeus in 1758 for a domestic cat. Felis catus domesticus was proposed by Johann Christian Polycarp Erxleben in 1777. Felis daemon proposed by Konstantin Satunin in 1904 was a black cat from the Transcaucasus, later identified as a domestic cat.

In 2003, the International Commission on Zoological Nomenclature ruled that the domestic cat is a distinct species, namely Felis catus. In 2007, it was considered a subspecies, F. silvestris catus, of the European wildcat (F. silvestris) following results of phylogenetic research. In 2017, the IUCN Cat Classification Taskforce followed the recommendation of the ICZN in regarding the domestic cat as a distinct species, Felis catus.

Evolution
Main article: Cat evolution
The domestic cat is a member of the Felidae, a family that had a common ancestor about 10 to 15 million years ago. The evolutionary radiation of the Felidae began in Asia during the Miocene around 8.38 to 14.45 million years ago. Analysis of mitochondrial DNA of all Felidae species indicates a radiation at 6.46 to 16.76 million years ago. The genus Felis genetically diverged from other Felidae around 6 to 7 million years ago. Results of phylogenetic research shows that the wild members of this genus evolved through sympatric or parapatric speciation, whereas the domestic cat evolved through artificial selection. The domestic cat and its closest wild ancestor are diploid and both possess 38 chromosomes and roughly 20,000 genes.

Domestication
See also: Domestication of the cat and Cats in ancient Egypt
It was long thought that the domestication of the cat began in ancient Egypt, where cats were venerated from around 3100 BC, However, the earliest known indication for the taming of an African wildcat was excavated close by a human Neolithic grave in Shillourokambos, southern Cyprus, dating to about 7500–7200 BC. Since there is no evidence of native mammalian fauna on Cyprus, the inhabitants of this Neolithic village most likely brought the cat and other wild mammals to the island from the Middle Eastern mainland. Scientists therefore assume that African wildcats were attracted to early human settlements in the Fertile Crescent by rodents, in particular the house mouse (Mus musculus), and were tamed by Neolithic farmers. This mutual relationship between early farmers and tamed cats lasted thousands of years. As agricultural practices spread, so did tame and domesticated cats. Wildcats of Egypt contributed to the maternal gene pool of the domestic cat at a later time.
The earliest known evidence for the occurrence of the domestic cat in Greece dates to around 1200 BC. Greek, Phoenician, Carthaginian and Etruscan traders introduced domestic cats to southern Europe. During the Roman Empire they were introduced to Corsica and Sardinia before the beginning of the 1st millennium. By the 5th century BC, they were familiar animals around settlements in Magna Graecia and Etruria. By the end of the Western Roman Empire in the 5th century, the Egyptian domestic cat lineage had arrived in a Baltic Sea port in northern Germany.

The leopard cat (Prionailurus bengalensis) was tamed independently in China around 5500 BC. This line of partially domesticated cats leaves no trace in the domestic cat populations of today.

During domestication, cats have undergone only minor changes in anatomy and behavior, and they are still capable of surviving in the wild. Several natural behaviors and characteristics of wildcats may have pre-adapted them for domestication as pets. These traits include their small size, social nature, obvious body language, love of play, and high intelligence. Captive Leopardus cats may also display affectionate behavior toward humans but were not domesticated. House cats often mate with feral cats. Hybridisation between domestic and other Felinae species is also possible, producing hybrids such as the Kellas cat in Scotland.

Development of cat breeds started in the mid 19th century. An analysis of the domestic cat genome revealed that the ancestral wildcat genome was significantly altered in the process of domestication, as specific mutations were selected to develop cat breeds. Most breeds are founded on random-bred domestic cats. Genetic diversity of these breeds varies between regions, and is lowest in purebred populations, which show more than 20 deleterious genetic disorders.

Characteristics
Main article: Cat anatomy
Size
The domestic cat has a smaller skull and shorter bones than the European wildcat. It averages about 46 cm (18 in) in head-to-body length and 23–25 cm (9.1–9.8 in) in height, with about 30 cm (12 in) long tails. Males are larger than females. Adult domestic cats typically weigh 4–5 kg (8.8–11.0 lb).

Skeleton
Cats have seven cervical vertebrae (as do most mammals); 13 thoracic vertebrae (humans have 12); seven lumbar vertebrae (humans have five); three sacral vertebrae (as do most mammals, but humans have five); and a variable number of caudal vertebrae in the tail (humans have only three to five vestigial caudal vertebrae, fused into an internal coccyx).  The extra lumbar and thoracic vertebrae account for the cat's spinal mobility and flexibility. Attached to the spine are 13 ribs, the shoulder, and the pelvis.  Unlike human arms, cat forelimbs are attached to the shoulder by free-floating clavicle bones which allow them to pass their body through any space into which they can fit their head.

Skull
The cat skull is unusual among mammals in having very large eye sockets and a powerful specialized jaw.  Within the jaw, cats have teeth adapted for killing prey and tearing meat. When it overpowers its prey, a cat delivers a lethal neck bite with its two long canine teeth, inserting them between two of the prey's vertebrae and severing its spinal cord, causing irreversible paralysis and death. Compared to other felines, domestic cats have narrowly spaced canine teeth relative to the size of their jaw, which is an adaptation to their preferred prey of small rodents, which have small vertebrae.

The premolar and first molar together compose the carnassial pair on each side of the mouth, which efficiently shears meat into small pieces, like a pair of scissors. These are vital in feeding, since cats' small molars cannot chew food effectively, and cats are largely incapable of mastication.:  Cats tend to have better teeth than most humans, with decay generally less likely because of a thicker protective layer of enamel, a less damaging saliva, less retention of food particles between teeth, and a diet mostly devoid of sugar. Nonetheless, they are subject to occasional tooth loss and infection.

Claws
Cats have protractible and retractable claws. In their normal, relaxed position, the claws are sheathed with the skin and fur around the paw's toe pads. This keeps the claws sharp by preventing wear from contact with the ground and allows for the silent stalking of prey. The claws on the forefeet are typically sharper than those on the hindfeet. Cats can voluntarily extend their claws on one or more paws. They may extend their claws in hunting or self-defense, climbing, kneading, or for extra traction on soft surfaces. Cats shed the outside layer of their claw sheaths when scratching rough surfaces.

Most cats have five claws on their front paws and four on their rear paws. The dewclaw is proximal to the other claws. More proximally is a protrusion which appears to be a sixth "finger". This special feature of the front paws on the inside of the wrists has no function in normal walking but is thought to be an antiskidding device used while jumping. Some cat breeds are prone to having extra digits ("polydactyly"). Polydactylous cats occur along North America's northeast coast and in Great Britain.

Ambulation
The cat is digitigrade. It walks on the toes, with the bones of the feet making up the lower part of the visible leg. Unlike most mammals, it uses a "pacing" gait and moves both legs on one side of the body before the legs on the other side. It registers directly by placing each hind paw close to the track of the corresponding fore paw, minimizing noise and visible tracks. This also provides sure footing for hind paws when navigating rough terrain. As it speeds up from walking to trotting, its gait changes to a "diagonal" gait: The diagonally opposite hind and fore legs move simultaneously.

Balance
Cats are generally fond of sitting in high places or perching. A higher place may serve as a concealed site from which to hunt; domestic cats strike prey by pouncing from a perch such as a tree branch. Another possible explanation is that height gives the cat a better observation point, allowing it to survey its territory. A cat falling from heights of up to 3 m (9.8 ft) can right itself and land on its paws.

During a fall from a high place, a cat reflexively twists its body and rights itself to land on its feet using its acute sense of balance and flexibility. This reflex is known as the cat righting reflex. A cat always rights itself in the same way during a fall, if it has enough time to do so, which is the case in falls of 90 cm (3.0 ft) or more. How cats are able to right themselves when falling has been investigated as the "falling cat problem".

Coats
Main article: Cat coat genetics
The cat family (Felidae) can pass down many colors and patterns to their offspring. The domestic cat genes MC1R and ASIP allow for the variety of color in coats. The feline ASIP gene consists of three coding exons. Three novel microsatellite markers linked to ASIP were isolated from a domestic cat BAC clone containing this gene and were used to perform linkage analysis in a pedigree of 89 domestic cats that segregated for melanism.[citation needed]

Senses
Main article: Cat senses
Vision
A cat's nictitating membrane shown as it blinks
Cats have excellent night vision and can see at only one-sixth the light level required for human vision.  This is partly the result of cat eyes having a tapetum lucidum, which reflects any light that passes through the retina back into the eye, thereby increasing the eye's sensitivity to dim light. Large pupils are an adaptation to dim light. The domestic cat has slit pupils, which allow it to focus bright light without chromatic aberration. At low light, a cat's pupils expand to cover most of the exposed surface of its eyes. The domestic cat has rather poor color vision and only two types of cone cells, optimized for sensitivity to blue and yellowish green; its ability to distinguish between red and green is limited. A response to middle wavelengths from a system other than the rod cells might be due to a third type of cone. This appears to be an adaptation to low light levels rather than representing true trichromatic vision. Cats also have a nictitating membrane, allowing them to blink without hindering their vision.

Hearing
The domestic cat's hearing is most acute in the range of 500 Hz to 32 kHz. It can detect an extremely broad range of frequencies ranging from 55 Hz to 79 kHz, whereas humans can only detect frequencies between 20 Hz and 20 kHz. It can hear a range of 10.5 octaves, while humans and dogs can hear ranges of about 9 octaves. Its hearing sensitivity is enhanced by its large movable outer ears, the pinnae, which amplify sounds and help detect the location of a noise. It can detect ultrasound, which enables it to detect ultrasonic calls made by rodent prey. Recent research has shown that cats have socio-spatial cognitive abilities to create mental maps of owners' locations based on hearing owners' voices.

Smell
Cats have an acute sense of smell, due in part to their well-developed olfactory bulb and a large surface of olfactory mucosa, about 5.8 cm2 (0.90 in2) in area, which is about twice that of humans. Cats and many other animals have a Jacobson's organ in their mouths that is used in the behavioral process of flehmening. It allows them to sense certain aromas in a way that humans cannot. Cats are sensitive to pheromones such as 3-mercapto-3-methylbutan-1-ol, which they use to communicate through urine spraying and marking with scent glands. Many cats also respond strongly to plants that contain nepetalactone, especially catnip, as they can detect that substance at less than one part per billion. About 70–80% of cats are affected by nepetalactone. This response is also produced by other plants, such as silver vine (Actinidia polygama) and the herb valerian; it may be caused by the smell of these plants mimicking a pheromone and stimulating cats' social or sexual behaviors.

Taste
Cats have relatively few taste buds compared to humans (470 or so versus more than 9,000 on the human tongue). Domestic and wild cats share a taste receptor gene mutation that keeps their sweet taste buds from binding to sugary molecules, leaving them with no ability to taste sweetness. They, however, possess taste bud receptors specialized for acids, amino acids like protein, and bitter tastes. Their taste buds possess the receptors needed to detect umami. However, these receptors contain molecular changes that make the cat taste of umami different from that of humans. In humans, they detect the amino acids of glutamic acid and aspartic acid, but in cats they instead detect nucleotides, in this case inosine monophosphate and l-Histidine. These nucleotides are particularly enriched in tuna. This has been argued is why cats find tuna so palatable: as put by researchers into cat taste, "the specific combination of the high IMP and free l-Histidine contents of tuna" .. "produces a strong umami taste synergy that is highly preferred by cats". One of the researchers involved in this research has further claimed, "I think umami is as important for cats as sweet is for humans".[87]

Cats also have a distinct temperature preference for their food, preferring food with a temperature around 38 °C (100 °F) which is similar to that of a fresh kill; some cats reject cold food (which would signal to the cat that the "prey" item is long dead and therefore possibly toxic or decomposing).

Whiskers
To aid with navigation and sensation, cats have dozens of movable whiskers (vibrissae) over their body, especially their faces. These provide information on the width of gaps and on the location of objects in the dark, both by touching objects directly and by sensing air currents; they also trigger protective blink reflexes to protect the eyes from damage.: 47 

Behavior
See also: Cat behavior
Outdoor cats are active both day and night, although they tend to be slightly more active at night.[88] Domestic cats spend the majority of their time in the vicinity of their homes but can range many hundreds of meters from this central point. They establish territories that vary considerably in size, in one study ranging 7–28 ha (17–69 acres). The timing of cats' activity is quite flexible and varied but being low-light predators, they are generally crepuscular, which means they tend to be more active near dawn and dusk. However, house cats' behavior is also influenced by human activity and they may adapt to their owners' sleeping patterns to some extent.

Cats conserve energy by sleeping more than most animals, especially as they grow older. The daily duration of sleep varies, usually between 12 and 16 hours, with 13 and 14 being the average. Some cats can sleep as much as 20 hours. The term "cat nap" for a short rest refers to the cat's tendency to fall asleep (lightly) for a brief period. While asleep, cats experience short periods of rapid eye movement sleep often accompanied by muscle twitches, which suggests they are dreaming.

Sociability
The social behavior of the domestic cat ranges from widely dispersed individuals to feral cat colonies that gather around a food source, based on groups of co-operating females. Within such groups, one cat is usually dominant over the others. Each cat in a colony holds a distinct territory, with sexually active males having the largest territories, which are about 10 times larger than those of female cats and may overlap with several females' territories. These territories are marked by urine spraying, by rubbing objects at head height with secretions from facial glands, and by defecation. Between these territories are neutral areas where cats watch and greet one another without territorial conflicts. Outside these neutral areas, territory holders usually chase away stranger cats, at first by staring, hissing, and growling and, if that does not work, by short but noisy and violent attacks. Despite this colonial organization, cats do not have a social survival strategy or a herd behavior, and always hunt alone.

Life in proximity to humans and other domestic animals has led to a symbiotic social adaptation in cats, and cats may express great affection toward humans or other animals. Ethologically, a cat's human keeper functions as if a mother surrogate. Adult cats live their lives in a kind of extended kittenhood, a form of behavioral neoteny. Their high-pitched sounds may mimic the cries of a hungry human infant, making them particularly difficult for humans to ignore. Some pet cats are poorly socialized. In particular, older cats show aggressiveness toward newly arrived kittens, which include biting and scratching; this type of behavior is known as feline asocial aggression.

Redirected aggression is a common form of aggression which can occur in multiple cat households. In redirected aggression there is usually something that agitates the cat: this could be a sight, sound, or another source of stimuli which causes a heightened level of anxiety or arousal. If the cat cannot attack the stimuli, it may direct anger elsewhere by attacking or directing aggression to the nearest cat, dog, human or other being.

Domestic cats' scent rubbing behavior toward humans or other cats is thought to be a feline means for social bonding.

Communication
Main article: Cat communication
Domestic cats use many vocalizations for communication, including purring, trilling, hissing, growling/snarling, grunting, and several different forms of meowing. Their body language, including position of ears and tail, relaxation of the whole body, and kneading of the paws, are all indicators of mood. The tail and ears are particularly important social signal mechanisms in cats. A raised tail indicates a friendly greeting, and flattened ears indicate hostility. Tail-raising also indicates the cat's position in the group's social hierarchy, with dominant individuals raising their tails less often than subordinate ones. Feral cats are generally silent.: 208  Nose-to-nose touching is also a common greeting and may be followed by social grooming, which is solicited by one of the cats raising and tilting its head.

Purring may have developed as an evolutionary advantage as a signaling mechanism of reassurance between mother cats and nursing kittens, who are thought to use it as a care-soliciting signal. Post-nursing cats also often purr as a sign of contentment: when being petted, becoming relaxed, or eating. Even though purring is popularly interpreted as indicative of pleasure, it has been recorded in a wide variety of circumstances, most of which involve physical contact between the cat and another, presumably trusted individual. Some cats have been observed to purr continuously when chronically ill or in apparent pain.

The exact mechanism by which cats purr has long been elusive, but it has been proposed that purring is generated via a series of sudden build-ups and releases of pressure as the glottis is opened and closed, which causes the vocal folds to separate forcefully. The laryngeal muscles in control of the glottis are thought to be driven by a neural oscillator which generates a cycle of contraction and release every 30–40 milliseconds (giving a frequency of 33 to 25 Hz).

Domestic cats observed in a rescue facility have total of 276 distinct facial expressions based on 26 different facial movements; each facial expression corresponds to different social functions that are likely influenced by domestication.

Grooming
Cats are known for spending considerable amounts of time licking their coats to keep them clean. The cat's tongue has backward-facing spines about 500 μm long, which are called papillae. These contain keratin which makes them rigid so the papillae act like a hairbrush. Some cats, particularly longhaired cats, occasionally regurgitate hairballs of fur that have collected in their stomachs from grooming. These clumps of fur are usually sausage-shaped and about 2–3 cm (0.79–1.18 in) long. Hairballs can be prevented with remedies that ease elimination of the hair through the gut, as well as regular grooming of the coat with a comb or stiff brush.

Fighting
Among domestic cats, males are more likely to fight than females. Among feral cats, the most common reason for cat fighting is competition between two males to mate with a female. In such cases, most fights are won by the heavier male. Another common reason for fighting in domestic cats is the difficulty of establishing territories within a small home. Female cats also fight over territory or to defend their kittens. Neutering will decrease or eliminate this behavior in many cases, suggesting that the behavior is linked to sex hormones.

When cats become aggressive, they try to make themselves appear larger and more threatening by raising their fur, arching their backs, turning sideways and hissing or spitting. Often, the ears are pointed down and back to avoid damage to the inner ear and potentially listen for any changes behind them while focused forward. Cats may also vocalize loudly and bare their teeth in an effort to further intimidate their opponents. Fights usually consist of grappling and delivering powerful slaps to the face and body with the forepaws as well as bites. Cats also throw themselves to the ground in a defensive posture to rake their opponent's belly with their powerful hind legs.

Serious damage is rare, as the fights are usually short in duration, with the loser running away with little more than a few scratches to the face and ears. Fights for mating rights are typically more severe and injuries may include deep puncture wounds and lacerations. Normally, serious injuries from fighting are limited to infections of scratches and bites, though these can occasionally kill cats if untreated. In addition, bites are probably the main route of transmission of feline immunodeficiency virus. Sexually active males are usually involved in many fights during their lives, and often have decidedly battered faces with obvious scars and cuts to their ears and nose. Cats are willing to threaten animals larger than them to defend their territory, such as dogs and foxes.

Hunting and feeding
See also: Cat food
The shape and structure of cats' cheeks is insufficient to allow them to take in liquids using suction. Therefore, when drinking they lap with the tongue to draw liquid upward into their mouths. Lapping at a rate of four times a second, the cat touches the smooth tip of its tongue to the surface of the water, and quickly retracts it like a corkscrew, drawing water upward.

Feral cats and free-fed house cats consume several small meals in a day. The frequency and size of meals varies between individuals. They select food based on its temperature, smell and texture; they dislike chilled foods and respond most strongly to moist foods rich in amino acids, which are similar to meat. Cats reject novel flavors (a response termed neophobia) and learn quickly to avoid foods that have tasted unpleasant in the past. It is also a common misconception that cats like milk/cream, as they tend to avoid sweet food and milk. Most adult cats are lactose intolerant; the sugar in milk is not easily digested and may cause soft stools or diarrhea. Some also develop odd eating habits and like to eat or chew on things like wool, plastic, cables, paper, string, aluminum foil, or even coal. This condition, pica, can threaten their health, depending on the amount and toxicity of the items eaten.

Cats hunt small prey, primarily birds and rodents, and are often used as a form of pest control. Other common small creatures such as lizards and snakes may also become prey. Cats use two hunting strategies, either stalking prey actively, or waiting in ambush until an animal comes close enough to be captured. The strategy used depends on the prey species in the area, with cats waiting in ambush outside burrows, but tending to actively stalk birds.: 153  Domestic cats are a major predator of wildlife in the United States, killing an estimated 1.3 to 4.0 billion birds and 6.3 to 22.3 billion mammals annually.

Certain species appear more susceptible than others; in one English village, for example, 30% of house sparrow mortality was linked to the domestic cat. In the recovery of ringed robins (Erithacus rubecula) and dunnocks (Prunella modularis) in Britain, 31% of deaths were a result of cat predation. In parts of North America, the presence of larger carnivores such as coyotes which prey on cats and other small predators reduces the effect of predation by cats and other small predators such as opossums and raccoons on bird numbers and variety.

Perhaps the best-known element of cats' hunting behavior, which is commonly misunderstood and often appalls cat owners because it looks like torture, is that cats often appear to "play" with prey by releasing and recapturing it. This cat and mouse behavior is due to an instinctive imperative to ensure that the prey is weak enough to be killed without endangering the cat.

Another poorly understood element of cat hunting behavior is the presentation of prey to human guardians. One explanation is that cats adopt humans into their social group and share excess kill with others in the group according to the dominance hierarchy, in which humans are reacted to as if they are at or near the top. Another explanation is that they attempt to teach their guardians to hunt or to help their human as if feeding "an elderly cat, or an inept kitten". This hypothesis is inconsistent with the fact that male cats also bring home prey, despite males having negligible involvement in raising kittens.:

Play
Main article: Cat play and toys
Domestic cats, especially young kittens, are known for their love of play. This behavior mimics hunting and is important in helping kittens learn to stalk, capture, and kill prey. Cats also engage in play fighting, with each other and with humans. This behavior may be a way for cats to practice the skills needed for real combat, and might also reduce any fear they associate with launching attacks on other animals.

Cats also tend to play with toys more when they are hungry. Owing to the close similarity between play and hunting, cats prefer to play with objects that resemble prey, such as small furry toys that move rapidly, but rapidly lose interest. They become habituated to a toy they have played with before. String is often used as a toy, but if it is eaten, it can become caught at the base of the cat's tongue and then move into the intestines, a medical emergency which can cause serious illness, even death. Owing to the risks posed by cats eating string, it is sometimes replaced with a laser pointer's dot, which cats may chase.

Reproduction
See also: Kitten
The cat secretes and perceives pheromones. Female cats, called queens, are polyestrous with several estrus cycles during a year, lasting usually 21 days. They are usually ready to mate between early February and August in northern temperate zones and throughout the year in equatorial regions.

Several males, called tomcats, are attracted to a female in heat. They fight over her, and the victor wins the right to mate. At first, the female rejects the male, but eventually, the female allows the male to mate. The female utters a loud yowl as the male pulls out of her because a male cat's penis has a band of about 120–150 backward-pointing penile spines, which are about 1 mm (0.039 in) long; upon withdrawal of the penis, the spines may provide the female with increased sexual stimulation, which acts to induce ovulation.

After mating, the female cleans her vulva thoroughly. If a male attempts to mate with her at this point, the female attacks him. After about 20 to 30 minutes, once the female is finished grooming, the cycle will repeat. Because ovulation is not always triggered by a single mating, females may not be impregnated by the first male with which they mate. Furthermore, cats are superfecund; that is, a female may mate with more than one male when she is in heat, with the result that different kittens in a litter may have different fathers.

The morula forms 124 hours after conception. At 148 hours, early blastocysts form. At 10–12 days, implantation occurs. The gestation of queens lasts between 64 and 67 days, with an average of 65 days.

Data on the reproductive capacity of more than 2,300 free-ranging queens were collected during a study between May 1998 and October 2000. They had one to six kittens per litter, with an average of three kittens. They produced a mean of 1.4 litters per year, but a maximum of three litters in a year. Of 169 kittens, 127 died before they were six months old due to a trauma caused in most cases by dog attacks and road accidents. The first litter is usually smaller than subsequent litters. Kittens are weaned between six and seven weeks of age. Queens normally reach sexual maturity at 5–10 months, and males at 5–7 months. This varies depending on breed. Kittens reach puberty at the age of 9–10 months.

Cats are ready to go to new homes at about 12 weeks of age, when they are ready to leave their mother. They can be surgically sterilized (spayed or castrated) as early as seven weeks to limit unwanted reproduction. This surgery also prevents undesirable sex-related behavior, such as aggression, territory marking (spraying urine) in males and yowling (calling) in females. Traditionally, this surgery was performed at around six to nine months of age, but it is increasingly being performed before puberty, at about three to six months. In the United States, about 80% of household cats are neutered.

Lifespan and health
Main articles: Cat health and Aging in cats
The average lifespan of pet cats has risen in recent decades. In the early 1980s, it was about seven years,: 33  rising to 9.4 years in 1995: 33  and an average of about 13 years as of 2014 and 2023. Some cats have been reported as surviving into their 30s, with the oldest known cat dying at a verified age of 38.

Neutering increases life expectancy: one study found castrated male cats live twice as long as intact males, while spayed female cats live 62% longer than intact females.: 35  Having a cat neutered confers health benefits, because castrated males cannot develop testicular cancer, spayed females cannot develop uterine or ovarian cancer, and both have a reduced risk of mammary cancer.

Disease
Main article: List of feline diseases
About 250 heritable genetic disorders have been identified in cats, many similar to human inborn errors of metabolism. The high level of similarity among the metabolism of mammals allows many of these feline diseases to be diagnosed using genetic tests that were originally developed for use in humans, as well as the use of cats as animal models in the study of the human diseases. Diseases affecting domestic cats include acute infections, parasitic infestations, injuries, and chronic diseases such as kidney disease, thyroid disease, and arthritis. Vaccinations are available for many infectious diseases, as are treatments to eliminate parasites such as worms, ticks, and fleas.

Ecology
Habitats
The domestic cat is a cosmopolitan species and occurs across much of the world. It is adaptable and now present on all continents except Antarctica, and on 118 of the 131 main groups of islands, even on the isolated Kerguelen Islands. Due to its ability to thrive in almost any terrestrial habitat, it is among the world's most invasive species. It lives on small islands with no human inhabitants. Feral cats can live in forests, grasslands, tundra, coastal areas, agricultural land, scrublands, urban areas, and wetlands.

The unwantedness that leads to the domestic cat being treated as an invasive species is twofold. On one hand, as it is little altered from the wildcat, it can readily interbreed with the wildcat. This hybridization poses a danger to the genetic distinctiveness of some wildcat populations, particularly in Scotland and Hungary, possibly also the Iberian Peninsula, and where protected natural areas are close to human-dominated landscapes, such as Kruger National Park in South Africa. However, its introduction to places where no native felines are present also contributes to the decline of native species.

Ferality
Main article: Feral cat
Feral cats are domestic cats that were born in or have reverted to a wild state. They are unfamiliar with and wary of humans and roam freely in urban and rural areas. The numbers of feral cats is not known, but estimates of the United States feral population range from 25 to 60 million. Feral cats may live alone, but most are found in large colonies, which occupy a specific territory and are usually associated with a source of food. Famous feral cat colonies are found in Rome around the Colosseum and Forum Romanum, with cats at some of these sites being fed and given medical attention by volunteers.

Public attitudes toward feral cats vary widely, from seeing them as free-ranging pets to regarding them as vermin.

Some feral cats can be successfully socialized and 're-tamed' for adoption; young cats, especially kittens and cats that have had prior experience and contact with humans are the most receptive to these efforts.

Impact on wildlife
Main article: Cat predation on wildlife
On islands, birds can contribute as much as 60% of a cat's diet. In nearly all cases, the cat cannot be identified as the sole cause for reducing the numbers of island birds, and in some instances, eradication of cats has caused a "mesopredator release" effect; where the suppression of top carnivores creates an abundance of smaller predators that cause a severe decline in their shared prey. Domestic cats are a contributing factor to the decline of many species, a factor that has ultimately led, in some cases, to extinction. The South Island piopio, Chatham rail, and the New Zealand merganser are a few from a long list, with the most extreme case being the flightless Lyall's wren, which was driven to extinction only a few years after its discovery. One feral cat in New Zealand killed 102 New Zealand lesser short-tailed bats in seven days. In the US, feral and free-ranging domestic cats kill an estimated 6.3 – 22.3 billion mammals annually.

In Australia, the impact of cats on mammal populations is even greater than the impact of habitat loss. More than one million reptiles are killed by feral cats each day, representing 258 species. Cats have contributed to the extinction of the Navassa curly-tailed lizard and Chioninia coctei.

Interaction with humans
Main article: Human interaction with cats
Cats are common pets throughout the world, and their worldwide population as of 2007 exceeded 500 million. As of 2017, the domestic cat was the second most popular pet in the United States, with 95.6 million cats owned and around 42 million households owning at least one cat. In the United Kingdom, 26% of adults have a cat, with an estimated population of 10.9 million pet cats as of 2020. As of 2021, there were an estimated 220 million owned and 480 million stray cats in the world.

Cats have been used for millennia to control rodents, notably around grain stores and aboard ships, and both uses extend to the present day.

As well as being kept as pets, cats are also used in the international fur trade and leather industries for making coats, hats, blankets, stuffed toys, shoes, gloves, and musical instruments. About 24 cats are needed to make a cat-fur coat. This use has been outlawed in the United States since 2000 and in the European Union (as well as the United Kingdom) since 2007.

Cat pelts have been used for superstitious purposes as part of the practice of witchcraft, and are still made into blankets in Switzerland as traditional medicine thought to cure rheumatism.

A few attempts to build a cat census have been made over the years, both through associations or national and international organizations (such as that of the Canadian Federation of Humane Societies) and over the Internet, but such a task does not seem simple to achieve. General estimates for the global population of domestic cats range widely from anywhere between 200 million to 600 million. Walter Chandoha made his career photographing cats after his 1949 images of Loco, an especially charming stray taken in, were published around the world. He is reported to have photographed 90,000 cats during his career and maintained an archive of 225,000 images that he drew from for publications during his lifetime.

Shows
Main article: Cat show
A cat show is a judged event in which the owners of cats compete to win titles in various cat-registering organizations by entering their cats to be judged after a breed standard. It is often required that a cat must be healthy and vaccinated in order to participate in a cat show. Both pedigreed and non-purebred companion ("moggy") cats are admissible, although the rules differ depending on the organization. Competing cats are compared to the applicable breed standard, and assessed for temperament.

Infection
Main article: Feline zoonosis
Cats can be infected or infested with viruses, bacteria, fungus, protozoans, arthropods or worms that can transmit diseases to humans. In some cases, the cat exhibits no symptoms of the disease. The same disease can then become evident in a human. The likelihood that a person will become diseased depends on the age and immune status of the person. Humans who have cats living in their home or in close association are more likely to become infected. Others might also acquire infections from cat feces and parasites exiting the cat's body. Some of the infections of most concern include salmonella, cat-scratch disease and toxoplasmosis.

History and mythology
Main articles: Cultural depictions of cats and Cats in ancient Egypt
In ancient Egypt, cats were worshipped, and the goddess Bastet often depicted in cat form, sometimes taking on the war-like aspect of a lioness. The Greek historian Herodotus reported that killing a cat was forbidden, and when a household cat died, the entire family mourned and shaved their eyebrows. Families took their dead cats to the sacred city of Bubastis, where they were embalmed and buried in sacred repositories. Herodotus expressed astonishment at the domestic cats in Egypt, because he had only ever seen wildcats.

Ancient Greeks and Romans kept weasels as pets, which were seen as the ideal rodent-killers. The earliest unmistakable evidence of the Greeks having domestic cats comes from two coins from Magna Graecia dating to the mid-fifth century BC showing Iokastos and Phalanthos, the legendary founders of Rhegion and Taras respectively, playing with their pet cats. The usual ancient Greek word for 'cat' was ailouros, meaning 'thing with the waving tail'. Cats are rarely mentioned in ancient Greek literature. Aristotle remarked in his History of Animals that "female cats are naturally lecherous." The Greeks later syncretized their own goddess Artemis with the Egyptian goddess Bastet, adopting Bastet's associations with cats and ascribing them to Artemis. In Ovid's Metamorphoses, when the deities flee to Egypt and take animal forms, the goddess Diana turns into a cat.

Cats eventually displaced weasels as the pest control of choice because they were more pleasant to have around the house and were more enthusiastic hunters of mice. During the Middle Ages, many of Artemis's associations with cats were grafted onto the Virgin Mary. Cats are often shown in icons of Annunciation and of the Holy Family and, according to Italian folklore, on the same night that Mary gave birth to Jesus, a cat in Bethlehem gave birth to a kitten. Domestic cats were spread throughout much of the rest of the world during the Age of Discovery, as ships' cats were carried on sailing ships to control shipboard rodents and as good-luck charms.

Several ancient religions believed cats are exalted souls, companions or guides for humans, that are all-knowing but mute so they cannot influence decisions made by humans. In Japan, the maneki neko cat is a symbol of good fortune. In Norse mythology, Freyja, the goddess of love, beauty, and fertility, is depicted as riding a chariot drawn by cats. In Jewish legend, the first cat was living in the house of the first man Adam as a pet that got rid of mice. The cat was once partnering with the first dog before the latter broke an oath they had made which resulted in enmity between the descendants of these two animals. It is also written that neither cats nor foxes are represented in the water, while every other animal has an incarnation species in the water. Although no species are sacred in Islam, cats are revered by Muslims. Some Western writers have stated Muhammad had a favorite cat, Muezza. He is reported to have loved cats so much, "he would do without his cloak rather than disturb one that was sleeping on it". The story has no origin in early Muslim writers, and seems to confuse a story of a later Sufi saint, Ahmed ar-Rifa'i, centuries after Muhammad. One of the companions of Muhammad was known as Abu Hurayrah ("father of the kitten"), in reference to his documented affection to cats.

Superstitions and rituals
Many cultures have negative superstitions about cats. An example would be the belief that encountering a black cat ("crossing one's path") leads to bad luck, or that cats are witches' familiars used to augment a witch's powers and skills. The killing of cats in Medieval Ypres, Belgium, is commemorated in the innocuous present-day Kattenstoet (cat parade). In mid-16th century France, cats would be burnt alive as a form of entertainment, particularly during midsummer festivals. According to Norman Davies, the assembled people "shrieked with laughter as the animals, howling with pain, were singed, roasted, and finally carbonized". The remaining ashes were sometimes taken back home by the people for good luck.

According to a myth in many cultures, cats have multiple lives. In many countries, they are believed to have nine lives, but in Italy, Germany, Greece, Brazil and some Spanish-speaking regions, they are said to have seven lives, while in Arabic traditions, the number of lives is six. An early mention of the myth can be found in John Heywood's The Proverbs of John Heywood (1546)

Husband, (quoth she), ye studie, be merrie now,
And even as ye thinke now, so come to yow.
Nay not so, (quoth he), for my thought to tell right,
I thinke how you lay groning, wife, all last night.
Husband, a groning horse and a groning wife
Never faile their master, (quoth she), for my life.
No wife, a woman hath nine lives like a cat.

The myth is attributed to the natural suppleness and swiftness cats exhibit to escape life-threatening situations. Also lending credence to this myth is the fact that falling cats often land on their feet, using an instinctive righting reflex to twist their bodies around. Nonetheless, cats can still be injured or killed by a high fall.

Italian Locust - Short-Horned Grasshopper (Calliptamus Italicus) by millicand@rocketmail.com

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Italian Locust - Short-Horned Grasshopper (Calliptamus Italicus)

Calliptamus italicus, the Italian locust, is a species of 'short-horned grasshopper' belonging to the family Acrididae, subfamily Calliptaminae.

This species is native of the steppes of Central Asia, but it is also present in most of Europe, in the eastern Palearctic realm, in North Africa, and in the Near East.

Distribution and habitat
Calliptamus italicus is found in Western Europe and Central Asia. Its range extends from North Africa and the countries bordering the Mediterranean Sea to Central Europe, Central Asia, Mongolia and western Siberia. These grasshoppers can be encountered from July through October. It thrives in warm dry habitats with sparse vegetation cover such as grasslands and rocky steppes, old quarries, gravel pits, rock-strewn areas beside rivers, sand dunes and fallow land.

Description
Calliptamus italicus is a medium-sized grasshopper characterized by a significant sexual dimorphism. The adult males grow up to 14–26 millimetres (0.55–1.02 in) long, while females reach 21–40 millimetres (0.83–1.57 in) of length. This species is quite variable in size and colour. The basic coloration of the body varies from gray to brownish-reddish. The wings have a characteristic reddish or pinkish coloration, better visible when the insect is in flight. Quite evident is the dilating membrane ('pallium') of the subgenital plate of males.

Ecology
Calliptamus italicus is a polyphagous species, able to feed upon various wild plants, but also on crops, especially legumes. Alfalfa (Medicago sativa) is among the species preferred by juveniles, but there have been reported sporadic cases of infestation on grains and grapevine. It feeds on a variety of plants in the families Asteraceae, Chenopodiaceae and Poaceae.

Their life cycle lasts one year. The egg-laying takes place in late August - early September, usually in rocky areas exposed to the south. The female lays eggs in the soil within an ootheca that can hold 25 to 55 eggs wrapped in a spongy secretion. The appearance of the larvae takes place in May–June; the first adults appear in July.

In certain circumstances this species may develop a tendency to gregariousness with formation of very numerous aggregates, potentially harmful to crops. It normally occurs in low densities in undisturbed sparse grassland but disappears when the land is cultivated. It occurs in high densities in uncultivated land that is invaded by Artemisia, and on overgrazed pastures with weeds and bare ground. Under these conditions it can become gregarious and form locust swarms. After the breakup of the USSR in 1991, much agricultural land was left uncultivated. This gave ideal conditions for the Italian locust to breed and build up in numbers, and Kazakhstan suffered a devastating locust plague between 1998 and 2001.

Subspecies
C. italicus var. albotibialis Nedelkov, 1907
C. italicus var. italicus Nedelkov, 1907

The following subspecies proposed in the past are no longer accepted. They are currently included in the nominal subspecies.
C. italicus var. carbonaria Uvarov, 1914 – C. coelesyriensis (Giglio-Tos, 1893)
C. italicus var. reductus Ramme, 1927 – C. italicus var. italicus Linnaeus, 1758)
C. italicus var. bilineata Puschnig, 1910 – C. italicus var. italicus Linnaeus, 1758)
C. italicus var. insularis Ramme, 1951 – C. italicus var. italicus Linnaeus, 1758)
C. italicus var. afghanus Ramme, 1952 – C. italicus var. italicus Linnaeus, 1758)
C. italicus var. grandis Ramme, 1927 – C. italicus var. italicus Linnaeus, 1758)
C. italicus var. gilvonigricans Voroncovskij, 1927 – C. italicus var. italicus Linnaeus, 1758)
C. italicus var. blandus Ivanov, 1888 – C. italicus var. italicus Linnaeus, 1758)

Short-Winged Meadow Katydid (Conocephalus Brevipennis) by millicand@rocketmail.com

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Short-Winged Meadow Katydid (Conocephalus Brevipennis)

Conocephalus brevipennis, the short-winged meadow katydid, is a species of meadow katydid in the family Tettigoniidae. It is found in North America and the Caribbean.

Insects in the family Tettigoniidae are commonly called katydids (especially in North America) or bush crickets. They have previously been known as "long-horned grasshoppers". More than 8,000 species are known. Part of the suborder Ensifera, the Tettigoniidae are the only extant (living) family in the superfamily Tettigonioidea.

Many species are nocturnal in habit, having strident mating calls and may exhibit mimicry or camouflage, commonly with shapes and colours similar to leaves.

Etymology
The family name Tettigoniidae is derived from the genus Tettigonia, of which the great green bush cricket is the type species; it was first described by Carl Linnaeus in 1758. In Latin tettigonia means a kind of small cicada, leafhopper; it is from the Greek τεττιγόνιον tettigonion, the diminutive of the imitative (onomatopoeic) τέττιξ, tettix, cicada. All of these names such as tettix with repeated sounds are onomatopoeic, imitating the stridulation of these insects. The common name katydid is also onomatopoeic and comes from the particularly loud, three-pulsed song, often rendered "ka-ty-did", of the nominate subspecies of the North American Pterophylla camellifolia, belonging to the subfamily Pseudophyllinae, which are known as "true katydids".

Description and life cycle
Tettigoniids range in size from as small as 5 mm (0.20 in) to as large as 130 mm (5.1 in). The smaller species typically live in drier or more stressful habitats which may lead to their small size. The small size is associated with greater agility, faster development, and lower nutritional needs. Tettigoniids are tree-living insects that are most commonly heard at night during summer and early fall. Tettigoniids may be distinguished from the grasshopper by the length of their filamentous antennae, which may exceed their own body length, while grasshoppers' antennae are always relatively short and thickened.

Life cycle
Where the eggs are deposited relates to the way the ovipositor is formed. It consists of up to three pairs of appendages formed to transmit the egg, to make a place for it, and place it properly. Tettigoniids have either sickle-shaped ovipositors which typically lay eggs in dead or living plant matter, or uniform long ovipositors which lay eggs in grass stems. When tettigoniids hatch, the nymphs often look like small, wingless versions of the adults, but in some species, the nymphs look nothing at all like the adult and rather mimic other species such as ants, spiders and assassin bugs, or flowers, to prevent predation. The nymphs remain in a mimic state only until they are large enough to escape predation. Once they complete their last molt (after about 5 successful molts), they are then prepared to mate.

Distribution
Tettigoniids are found on every continent except Antarctica. The vast majority of katydid species live in the tropical regions of the world. For example, the Amazon basin rain forest is home to over 2,000 species of katydids. However, katydids are found in the cool, dry temperate regions, as well, with about 255 species in North America.

Classification
The Tettigoniidae are a large family and have been divided into a number of subfamilies:

Austrosaginae (Australia)
Bradyporinae (southeast Europe, west & central Asia)
Conocephalinae (global)
Hetrodinae (Africa)
Hexacentrinae (pantropical, especially Asia)
Lipotactinae (Asia)
Listroscelidinae (Americas, Madagascar, Australia)
Meconematinae (global)
Mecopodinae (South America, Africa, Southeast Asia, Oceania)
Microtettigoniinae (Australia)
Phaneropterinae (global)
Phasmodinae (Australia)
Phyllophorinae (Australasia)
Pseudophyllinae (global)
Pterochrozinae (Central and South America)
Saginae (North America, Africa, Europe)
Tettigoniinae (global)
Tympanophorinae (Australia)
Zaprochilinae (Australia)

Golden-Bloomed Grey Longhorn Beetle (Agapanthia Villosoviridescens) by millicand@rocketmail.com

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Golden-Bloomed Grey Longhorn Beetle (Agapanthia Villosoviridescens)

Agapanthia villosoviridescens, also known as the golden-bloomed grey longhorn beetle, is a species of beetle in the subfamily Lamiinae, found in the Caucasus, Europe, Kazakhstan, the Near East, Russia and Turkey.

Description and habitat
The beetle is named for its golden-black colour, with a golden bloom on its elytron and thorax. It reaches a length of 10–22 millimetres (0.39–0.87 in).

Habitat
Their flight time is from May to August. For the larval development the species is quite polyphagous with a wide variety of hosts, probably including Aconitum, Angelica, Anthriscus, Artemisia, Aster, Carduus, Cirsium, Chaerophyllum, Eupatorium, Foeniculum, Gentiana, Helleborus, Heracleum, Peucedanum, Salvia, Senecio, Urtica and Veratrum album. The larvae develop in the stalks of the host plant, working their way down while growing, cutting off the stalk and creating pupal cells near ground level. Adults emerge through a newly cut exit hole in the side of the stalk.

Alpaca (Vicugna Pacos) by millicand@rocketmail.com

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Alpaca (Vicugna Pacos)

The alpaca (Lama pacos) is a species of South American camelid mammal. It is similar to, and often confused with, the llama. However, alpacas are often noticeably smaller than llamas. The two animals are closely related and can successfully crossbreed. Both species are believed to have been domesticated from their wild relatives, the vicuña and guanaco. There are two breeds of alpaca: the Suri alpaca and the Huacaya alpaca.

Alpacas are kept in herds that graze on the level heights of the Andes of Southern Peru, Western Bolivia, Ecuador, and Northern Chile at an altitude of 3,500 to 5,000 metres (11,000 to 16,000 feet) above sea level. Alpacas are considerably smaller than llamas, and unlike llamas, they were not bred to be working animals, but were bred specifically for their fiber. Alpaca fiber is used for making knitted and woven items, similar to sheep's wool. These items include blankets, sweaters, hats, gloves, scarves, a wide variety of textiles, and ponchos, in South America, as well as sweaters, socks, coats, and bedding in other parts of the world. The fiber comes in more than 52 natural colors as classified in Peru, 12 as classified in Australia, and 16 as classified in the United States.

Alpacas communicate through body language. The most common is spitting to show dominance when they are in distress, fearful, or feel agitated. Male alpacas are more aggressive than females, and tend to establish dominance within their herd group. In some cases, alpha males will immobilize the head and neck of a weaker or challenging male in order to show their strength and dominance.

In the textile industry, "alpaca" primarily refers to the hair of Peruvian alpacas, but more broadly it refers to a style of fabric originally made from alpaca hair, such as mohair, Icelandic sheep wool, or even high-quality wool from other breeds of sheep. In trade, distinctions are made between alpacas and the several styles of mohair and luster.

An adult alpaca generally is between 81 and 99 centimetres (32 and 39 inches) in height at the shoulders (withers). They usually weigh between 48 and 90 kilograms (106 and 198 pounds). Raised in the same conditions, the difference in weight can be small with males weighting around 22.3 kilograms (49 lb 3 oz) and females 21.3 kilograms (46 lb 15 oz).

Background

The relationship between alpacas and vicuñas was disputed for many years. In the 18th and 19th centuries, the four South American lamoid species were assigned scientific names. At that time, the alpaca was assumed to be descended from the llama, ignoring similarities in size, fleece and dentition between the alpaca and the vicuña. Classification was complicated by the fact that all four species of South American camelid can interbreed and produce fertile offspring. The advent of DNA technology made a more accurate classification possible.

In 2001, the alpaca genus classification changed from Lama pacos to Vicugna pacos, following the presentation of a paper on work by Miranda Kadwell et al. on alpaca DNA to the Royal Society showing the alpaca is descended from the vicuña, not the guanaco.

Origin and domestication
Alpacas were domesticated thousands of years ago. The Moche people of Northern Peru often used alpaca images in their art. There are no known wild alpacas, and its closest living relative, the vicuña (also native to South America), is the wild ancestor of the alpaca.

The family Camelidae first appeared in Americas 40–45 million years ago, during the Eocene period, from the common ancestor, Protylopus. The descendants divided into Camelini and Lamini tribes, taking different migratory patterns to Asia and South America, respectively. Although the camelids became extinct in North America around 3 million years ago, it flourished in the South with the species we see today. It was not until 2–5 million years ago, during the Pliocene, that the genus Hemiauchenia of the tribe Lamini split into Palaeolama and Lama; the latter would then split again into Lama and Vicugna upon migrating down to South America.

Remains of vicuña and guanaco dating around 12,000 years have been found throughout Peru. Their domesticated counterparts, the llama and alpaca, have been found mummified in the Moquegua valley, in the south of Peru, dating back 900 to 1000 years. Mummies found in this region show two breeds of alpacas. More precise analysis of bone and teeth of these mummies has demonstrated that alpacas were domesticated from the Vicugna vicugna. Other research, considering the behavioral and morphological characteristics of alpacas and their wild counterparts, seems to indicate that alpacas could find their origins in Lama guanicoe as well as Vicugna vicugna, or even a hybrid of both.

Genetic analysis shows a different picture of the origins of the alpaca. Analysis of mitochondrial DNA shows that most alpacas have guanaco mtDNA, and many also have vicuña mtDNA. But microsatellite data shows that alpaca DNA is much more similar to vicuña DNA than to guanaco DNA. This suggests that alpacas are descendants of the Vicugna vicugna, not of the Lama guanicoe. The discrepancy with mtDNA seems to be a result of the fact that mtDNA is only transmitted by the mother, and recent husbandry practices have caused hybridization between llamas (which primarily carry guanaco DNA) and alpacas. To the extent that many of today's domestic alpacas are the result of male alpacas bred to female llamas, this would explain the mtDNA consistent with guanacos. This situation has led to attempts to reclassify the alpaca as Vicugna pacos.

Breeds
The alpaca comes in two breeds, Suri and Huacaya, based on their fibers rather than scientific or European classifications.
(Museum of Osteology)
Huacaya alpacas are the most commonly found, constituting about 90% of the population. The Huacaya alpaca is thought to have originated in post-colonial Peru. This is due to their thicker fleece which makes them more suited to survive in the higher altitudes of the Andes after being pushed into the highlands of Peru with the arrival of the Spanish.

Suri alpacas represent a smaller portion of the total alpaca population, around 10%. They are thought to have been more prevalent in pre-Columbian Peru since they could be kept at a lower altitude where a thicker fleece was not needed for harsh weather conditions.

Behavior

Alpacas are social herd animals that live in family groups, consisting of a territorial alpha male, females, and their young ones. Alpacas warn the herd about intruders by making sharp, noisy inhalations that sound like a high-pitched bray. The herd may attack smaller predators with their front feet and can spit and kick. Their aggression towards members of the canid family (coyotes, foxes, dogs etc.) is exploited when alpacas are used as guard llamas for guarding sheep.

Alpacas can sometimes be aggressive, but they can also be very gentle, intelligent, and extremely observant. For the most part, alpacas are very quiet, but male alpacas are more energetic when they get involved in fighting with other alpacas. When they prey, they are cautious but also nervous when they feel any type of threat. They can feel threatened when a person or another alpaca comes up from behind them.

Alpacas set their own boundaries of "personal space" within their families and groups.They make a hierarchy in some sense, and each alpaca is aware of the dominant animals in each group. Body language is the key to their communication. It helps to maintain their order. One example of their body communication includes a pose named broadside, where their ears are pulled back and they stand sideways. This pose is used when male alpacas are defending their territory.

When they are young, they tend to follow larger objects and to sit near or under them. An example of this is a baby alpaca with its mother. This can also apply when an alpaca passes by an older alpaca.

Training
Alpacas are generally very trainable and usually respond to reward, most commonly in the form of food. They can usually be petted without getting agitated, especially if one avoids petting the head or neck. Alpacas are usually quite easy to herd, even in large groups. However, during herding, it is recommended for the handler to approach the animals slowly and quietly, as failing to do so can result in danger for both the animals and the handler.

Alpacas and llamas have started showing up in U.S. nursing homes and hospitals as trained, certified therapy animals. The Mayo Clinic says animal-assisted therapy can reduce pain, depression, anxiety, and fatigue. This type of animal therapy is growing in popularity, and there are several organizations throughout the United States that participate.

Spitting
Not all alpacas spit, but all are capable of doing so. "Spit" is somewhat euphemistic; occasionally the projectile contains only air and a little saliva, although alpacas commonly bring up acidic stomach contents (generally a green, grassy mix) and project it onto their chosen targets. Spitting is mostly reserved for other alpacas, but an alpaca will also occasionally spit at a human.

Spitting can result in what is called "sour mouth". Sour mouth is characterized by "a loose-hanging lower lip and a gaping mouth."

Alpacas can spit for several reasons. A female alpaca spits when she is not interested in a male alpaca, typically when she thinks that she is already impregnated. Both sexes of alpaca keep others away from their food, or anything they have their eyes on. Most give a slight warning before spitting by blowing air out and raising their heads, giving their ears a "pinned" appearance.

Alpacas can spit up to ten feet if they need to. For example, if another animal does not back off, the alpaca will throw up its stomach contents, resulting in a lot of spit.

Some signs of stress which can lead to their spitting habits include: humming, a wrinkle under their eye, drooling, rapid breathing, and stomping their feet. When alpacas show any sign of interest or alertness, they tend to sniff their surroundings, watch closely, or stand quietly in place and stare.

When it comes to reproduction, they spit because it is a response triggered by the progesterone levels being increased, which is associated with ovulation.

Hygiene
Alpacas use a communal dung pile, where they do not graze. This behaviour tends to limit the spread of internal parasites. Generally, males have much tidier, and fewer dung piles than females, which tend to stand in a line and all go at once. One female approaches the dung pile and begins to urinate and/or defecate, and the rest of the herd often follows. Alpaca waste is collected and used as garden fertilizer or even natural fertilizer.

Because of their preference for using a dung pile for excreting bodily waste, some alpacas have been successfully house-trained.

Alpacas develop dental hygiene problems which affect their eating and behavior. Warning signs include protracted chewing while eating, or food spilling out of their mouths. Poor body condition and sunken cheeks are also telltales of dental problems.

Alpacas make a variety of sounds:

Humming: When alpacas are born, the mother and baby hum constantly. They also hum as a sign of distress, especially when they are separated from their herd. Alpacas may also hum when curious, happy, worried or cautious.
Snorting: Alpacas snort when another alpaca is invading its space.
Grumbling: Alpacas grumble to warn each other. For example, when one is invading another's personal space, it sounds like gurgling.
Clucking: Similar to a hen's cluck, alpacas cluck when a mother is concerned for her cria. Male alpacas cluck to signal friendly behavior.
Screaming: Their screams are extremely deafening and loud. They will scream when they are not handled correctly or when they are being attacked by a potential enemy.
Screeching: A bird-like cry, presumably intended to terrify the opponent. This sound is typically used by male alpacas when they are in a fight over dominance. When a female screeches, it is more of a growl when she is angry.

Reproduction
Females are induced ovulators; meaning the act of mating and the presence of semen causes them to ovulate. Females usually conceive after just one breeding, but occasionally do have trouble conceiving. Artificial insemination is technically difficult, expensive and not common, but it can be accomplished. Embryo transfer is more widespread.

A male is usually ready to mate for the first time between two and three years of age. It is not advisable to allow a young female to be bred until she is mature and has reached two-thirds of her mature weight. Over-breeding a young female before conception is possibly a common cause of uterine infections. As the age of maturation varies greatly between individuals, it is usually recommended that novice breeders wait until females are 18 months of age or older before initiating breeding.

Alpacas can breed at any time throughout the year but it is more difficult to breed in the winter. Most breed during autumn or late spring. The most popular way to have alpacas mate is pen mating. Pen mating is when they move both the female and the desired male into a pen. Another way is paddock mating where one male alpaca is let loose in the paddock with several female alpacas.

The gestation period is, on average, 11.5 months, and usually results in a single offspring, or cria. Twins are rare, occurring about once per 1000 deliveries. Cria are generally between 15 and 19 pounds, and are standing 30 to 90 minutes after birth. After a female gives birth, she is generally receptive to breeding again after about two weeks. Crias may be weaned through human intervention at about six months old and 60 pounds, but many breeders prefer to allow the female to decide when to wean her offspring; they can be weaned earlier or later depending on their size and emotional maturity.

The average lifespan of an alpaca is between 15 and 20 years, and the longest-lived alpaca on record is 27 years.


Pests and diseases
Cattle tuberculosis can also infect alpacas: Mycobacterium bovis also causes TB in this species worldwide. Krajewska‐Wędzina et al., 2020 detect M. bovis in individuals traded from the United Kingdom to Poland. To accomplish this they develop a seroassay which correctly identifies positive subjects which are false negative for a common skin test. Krajewska‐Wędzina et al. also find that alpacas are unusual in mounting a competent early-infection immune response. Bernitz et al., 2021 believe this to generalise to all camelids.

Habitat and lifestyle
Alpacas can be found throughout most of South America. They typically live in temperate conditions in the mountains with high altitudes.

They are easy to care for since they are not limited to a specific type of environment. Animals such as flamingos, condors, spectacled bears, mountain lions, coyotes, llamas, and sheep live near alpacas when they are in their natural habitat.

Population
Alpacas are native to Peru, but can be found throughout the globe in captivity. Peru currently has the largest alpaca population, with over half the world's animals. The population declined drastically after the Spanish Conquistadors invaded the Andes mountains in 1532, after which 98% of the animals were destroyed. The Spanish also brought with them diseases that were fatal to alpacas.

European conquest forced the animals to move higher into the mountains, which remained there permanently. Although alpacas had almost been wiped out completely, they were rediscovered sometime during the 19th century by Europeans. After finding uses for them, the animals became important to societies during the industrial revolution.

In popular culture
Nuzzle and Scratch was a British children's television programme featuring two fictional alpacas that was first broadcast between 2008 and 2011.

Interest in alpacas grew as a result of Depp v. Heard, the 2022 trial in which Johnny Depp sued Amber Heard for defamation in Virginia after Heard wrote an op-ed saying she was a public victim of domestic violence. Depp testified, under oath, that he would not make another Pirates of the Caribbean film for "300 million dollars and a million alpacas".

Diet

Alpacas chew their food which ends up being mixed with their cud and saliva and then they swallow it. Alpacas usually eat 1.5% of their body weight daily for normal growth. They mainly need pasture grass, hay, or silage but some may also need supplemental energy and protein foods and they will also normally try to chew on almost anything (e.g. empty bottle). Most alpaca ranchers rotate their feeding grounds so the grass can regrow and fecal parasites may die before reusing the area. Pasture grass is a great source of protein. When seasons change, the grass loses or gains more protein. For example, in the spring, the pasture grass has about 20% protein while in the summer, it only has 6%. They need more energy supplements in the winter to produce body heat and warmth. They get their fiber from hay or from long stems which provides them with vitamin E. Green grass contains vitamin A and E.

Alpacas can eat natural unfertilized grass; however, ranchers can also supplement grass with low-protein grass hay. To provide selenium and other necessary vitamins, ranchers will feed their domestic alpacas a daily dose of grain to provide additional nutrients that are not fully obtained from their primary diet. Alpacas may obtain the necessary vitamins in their native grazing ranges.

Digestion
Alpacas, like other camelids, have a three-chambered stomach; combined with chewing cud, this three-chambered system allows maximum extraction of nutrients from low-quality forages. Alpacas are not ruminants, pseudo-ruminants, or modified ruminants, as there are many differences between the anatomy and physiology of a camelid and a ruminant stomach.

Alpacas will chew their food in a figure eight motion, swallow the food, and then pass it into one of the stomach's chambers. The first and second chambers (called C1 and C2) are anaerobic fermentation chambers where the fermentation process begins. The alpaca will further absorb nutrients and water in the first part of the third chamber. The end of the third chamber (called C3) is where the stomach secretes acids to digest food and is the likely place where an alpaca will have ulcers if stressed.

Poisonous plants
Many plants are poisonous to the alpaca, including the bracken fern, Madagascar ragwort, oleander, and some azaleas. In common with similar livestock, others include acorns, African rue, agave, amaryllis, autumn crocus, bear grass, broom snakeweed, buckwheat, ragweed, buttercups, calla lily, orange tree foliage, carnations, castor beans, and many others.

Fiber
Main article: Alpaca fiber
Alpacas are typically sheared once per year in the spring. Each shearing produces approximately 2.3 to 4.5 kilograms (5 to 10 pounds) of fiber per alpaca. An adult alpaca might produce 1.4 to 2.6 kilograms (50 to 90 ounces) of first-quality fiber as well as 1.4 to 2.8 kilograms (50 to 100 ounces) of second- and third-quality fiber. The quality of alpaca fiber is determined by how crimpy it is. Typically, the greater the number of small folds in the fiber, the greater the quality.

Prices
Alpacas were the subject of a speculative bubble between their introduction to North America in 1984 and the early 21st century. The price for American alpacas ranged from US$50 for a castrated male (gelding) to US$675,000 for the highest in the world, depending on breeding history, sex, and color. In 2006, researchers warned that the higher prices sought for alpaca breeding stock were largely speculative and not supported by market fundamentals, given the low inherent returns per head from the main end product, alpaca fiber, and prices into the $100s per head rather than $10,000s would be required for a commercially viable fiber production herd.

Marketed as "the investment you can hug" in television commercials by the Alpaca Owners and Breeders Association, the market for alpacas was almost entirely dependent on breeding and selling animals to new buyers, a classic sign of speculative bubbles in livestock. The bubble burst in 2007, with the price of alpaca breeding stock dropping by thousands of dollars each year thereafter. Many farmers found themselves unable to sell animals for any price, or even give them away.

It is possible to raise up to 25 alpacas per hectare (10/acre), as they have a designated area for waste products and keep their eating area away from their waste area. However, this ratio differs from country to country and is highly dependent on the quality of pasture available (in many desert locations it is generally only possible to run one to three animals per acre due to lack of suitable vegetation). Fiber quality is the primary variant in the price achieved for alpaca wool; in Australia, it is common to classify the fiber by the thickness of the individual hairs and by the amount of vegetable matter contained in the supplied shearings.

Livestock

Alpacas need to eat 1–2% of their body weight per day, so about two 27 kg (60 lb) bales of grass hay per month per animal. When formulating a proper diet for alpacas, water and hay analysis should be performed to determine the proper vitamin and mineral supplementation program. Two options are to provide free choice salt/mineral powder or feed a specially formulated ration. Indigenous to the highest regions of the Andes, this harsh environment has created an extremely hardy animal, so only minimal housing and predator fencing are needed. The alpacas' three-chambered stomachs allow for extremely efficient digestion. There are no viable seeds in the manure, because alpacas prefer to only eat tender plant leaves, and will not consume thick plant stems; therefore, alpaca manure does not need composting to enrich pastures or ornamental landscaping. Nail and teeth trimming are needed every six to twelve months, along with annual shearing.

Similar to ruminants, such as cattle and sheep, alpacas have only lower teeth at the front of their mouths; therefore, they do not pull the grass up by the roots. Rotating pastures is still important, though, as alpacas have a tendency to regraze an area repeatedly. Alpacas are fiber-producing animals; they do not need to be slaughtered to reap their product, and their fiber is a renewable resource that grows yearly.

Cultural presence

Alpacas are closely tied to cultural practices for Andeans people. Prior to colonization, the image of the alpaca was used in rituals and in their religious practices. Since the people in the region depended heavily on these animals for their sustenance, the alpaca was seen as a gift from Pachamama. Alpacas were used for their meat, fibers for clothing, and art, and their images in the form of conopas.

Conopas take their appearance from the Suri alpacas, with long locks flanking their sides and bangs covering the eyes, and a depression on the back. This depression is used in ritual practices, usually filled with coca leaves and fat from alpacas and lamas, to bring fertility and luck. While their use was prevalent before colonization, the attempts to convert the Andean people to Catholicism led to the acquisition of more than 3,400 conopas in Lima alone.

The origin of alpacas is depicted in legend; the legend states they came to be in the world after a goddess fell in love with a man. The goddess' father only allowed her to be with her lover if he cared for her herd of alpacas. On top of caring for the herd, he was to always carry a small animal for his entire life. As the goddess came into our world, the alpacas followed her. Everything was fine until the man set the small animal down, and the goddess fled back to her home. On her way back home, the man attempted to stop her and her herd from fleeing. While he was not able to stop her from returning, he was able to stop a few alpacas from returning. These alpacas who did not make it back are said to be seen today in the swampy lands in the Andes waiting for the end of the world, so they may return to their goddess.

Egyptian Grasshopper - Egyptian Locust (Anacridium Aegyptium) by millicand@rocketmail.com

© millicand@rocketmail.com, all rights reserved.

Egyptian Grasshopper - Egyptian Locust (Anacridium Aegyptium)

Anacridium aegyptium, the Egyptian grasshopper or Egyptian locust, is a species of insect belonging to the subfamily Cyrtacanthacridinae.

Subspecies
Anacridium aegyptium var. rubrispinum Bei-Bienko, 1948 - Anacridium rubrispinum Bei-Bienko, 1948

Distribution
A fairly common species, the Egyptian grasshopper is present in most of Europe, the Afrotropical realm, eastern Palearctic realm, the Near East, and North Africa, and has recently been observed in Cape Town, South Africa.

Habitat
These grasshoppers inhabit trees and shrubs, scrub land, maquis, and orchards in warm and bright environments, at an elevation from sea level to 1,500 m.

Description
grasshoppers. Adult males grow up to 30–56 mm (1.2–2.2 in) long, while females reach 46–70 mm (1.8–2.8 in) in length. Their bodies are usually gray, brown, or olive-coloured, and their antennae are relatively short and robust. The tibiae of the hind legs are blue, while the femora are orange. The hind femora have characteristic dark marks. They are also easily identified by their characteristic eyes, which have vertical black and white stripes. Their pronota show a dorsal orange stripe and several small white spots. The wings are clear with dark marks.

Biology
This species is a folivore, essentially feeding on leaves of various plants. It is a solitary species, harmless to crops. Adults are mainly seen in August and September, but they are active throughout the year. After mating, these grasshoppers overwinter as adults. Spawning occurs in spring just under the soil surface and the nymphs appear in April. These grasshoppers undergo several molts. Nymphs differ from adults in appearance; their color varies from yellow to bright green and ocher and the wings are absent or small, as they are gradually developed after each molt.

Alpaca (Vicugna Pacos) by millicand@rocketmail.com

© millicand@rocketmail.com, all rights reserved.

Alpaca (Vicugna Pacos)

The alpaca (Lama pacos) is a species of South American camelid mammal. It is similar to, and often confused with, the llama. However, alpacas are often noticeably smaller than llamas. The two animals are closely related and can successfully crossbreed. Both species are believed to have been domesticated from their wild relatives, the vicuña and guanaco. There are two breeds of alpaca: the Suri alpaca and the Huacaya alpaca.

Alpacas are kept in herds that graze on the level heights of the Andes of Southern Peru, Western Bolivia, Ecuador, and Northern Chile at an altitude of 3,500 to 5,000 metres (11,000 to 16,000 feet) above sea level. Alpacas are considerably smaller than llamas, and unlike llamas, they were not bred to be working animals, but were bred specifically for their fiber. Alpaca fiber is used for making knitted and woven items, similar to sheep's wool. These items include blankets, sweaters, hats, gloves, scarves, a wide variety of textiles, and ponchos, in South America, as well as sweaters, socks, coats, and bedding in other parts of the world. The fiber comes in more than 52 natural colors as classified in Peru, 12 as classified in Australia, and 16 as classified in the United States.

Alpacas communicate through body language. The most common is spitting to show dominance when they are in distress, fearful, or feel agitated. Male alpacas are more aggressive than females, and tend to establish dominance within their herd group. In some cases, alpha males will immobilize the head and neck of a weaker or challenging male in order to show their strength and dominance.

In the textile industry, "alpaca" primarily refers to the hair of Peruvian alpacas, but more broadly it refers to a style of fabric originally made from alpaca hair, such as mohair, Icelandic sheep wool, or even high-quality wool from other breeds of sheep. In trade, distinctions are made between alpacas and the several styles of mohair and luster.

An adult alpaca generally is between 81 and 99 centimetres (32 and 39 inches) in height at the shoulders (withers). They usually weigh between 48 and 90 kilograms (106 and 198 pounds). Raised in the same conditions, the difference in weight can be small with males weighting around 22.3 kilograms (49 lb 3 oz) and females 21.3 kilograms (46 lb 15 oz).

Background

The relationship between alpacas and vicuñas was disputed for many years. In the 18th and 19th centuries, the four South American lamoid species were assigned scientific names. At that time, the alpaca was assumed to be descended from the llama, ignoring similarities in size, fleece and dentition between the alpaca and the vicuña. Classification was complicated by the fact that all four species of South American camelid can interbreed and produce fertile offspring. The advent of DNA technology made a more accurate classification possible.

In 2001, the alpaca genus classification changed from Lama pacos to Vicugna pacos, following the presentation of a paper on work by Miranda Kadwell et al. on alpaca DNA to the Royal Society showing the alpaca is descended from the vicuña, not the guanaco.

Origin and domestication
Alpacas were domesticated thousands of years ago. The Moche people of Northern Peru often used alpaca images in their art. There are no known wild alpacas, and its closest living relative, the vicuña (also native to South America), is the wild ancestor of the alpaca.

The family Camelidae first appeared in Americas 40–45 million years ago, during the Eocene period, from the common ancestor, Protylopus. The descendants divided into Camelini and Lamini tribes, taking different migratory patterns to Asia and South America, respectively. Although the camelids became extinct in North America around 3 million years ago, it flourished in the South with the species we see today. It was not until 2–5 million years ago, during the Pliocene, that the genus Hemiauchenia of the tribe Lamini split into Palaeolama and Lama; the latter would then split again into Lama and Vicugna upon migrating down to South America.

Remains of vicuña and guanaco dating around 12,000 years have been found throughout Peru. Their domesticated counterparts, the llama and alpaca, have been found mummified in the Moquegua valley, in the south of Peru, dating back 900 to 1000 years. Mummies found in this region show two breeds of alpacas. More precise analysis of bone and teeth of these mummies has demonstrated that alpacas were domesticated from the Vicugna vicugna. Other research, considering the behavioral and morphological characteristics of alpacas and their wild counterparts, seems to indicate that alpacas could find their origins in Lama guanicoe as well as Vicugna vicugna, or even a hybrid of both.

Genetic analysis shows a different picture of the origins of the alpaca. Analysis of mitochondrial DNA shows that most alpacas have guanaco mtDNA, and many also have vicuña mtDNA. But microsatellite data shows that alpaca DNA is much more similar to vicuña DNA than to guanaco DNA. This suggests that alpacas are descendants of the Vicugna vicugna, not of the Lama guanicoe. The discrepancy with mtDNA seems to be a result of the fact that mtDNA is only transmitted by the mother, and recent husbandry practices have caused hybridization between llamas (which primarily carry guanaco DNA) and alpacas. To the extent that many of today's domestic alpacas are the result of male alpacas bred to female llamas, this would explain the mtDNA consistent with guanacos. This situation has led to attempts to reclassify the alpaca as Vicugna pacos.

Breeds
The alpaca comes in two breeds, Suri and Huacaya, based on their fibers rather than scientific or European classifications.
(Museum of Osteology)
Huacaya alpacas are the most commonly found, constituting about 90% of the population. The Huacaya alpaca is thought to have originated in post-colonial Peru. This is due to their thicker fleece which makes them more suited to survive in the higher altitudes of the Andes after being pushed into the highlands of Peru with the arrival of the Spanish.

Suri alpacas represent a smaller portion of the total alpaca population, around 10%. They are thought to have been more prevalent in pre-Columbian Peru since they could be kept at a lower altitude where a thicker fleece was not needed for harsh weather conditions.

Behavior

Alpacas are social herd animals that live in family groups, consisting of a territorial alpha male, females, and their young ones. Alpacas warn the herd about intruders by making sharp, noisy inhalations that sound like a high-pitched bray. The herd may attack smaller predators with their front feet and can spit and kick. Their aggression towards members of the canid family (coyotes, foxes, dogs etc.) is exploited when alpacas are used as guard llamas for guarding sheep.

Alpacas can sometimes be aggressive, but they can also be very gentle, intelligent, and extremely observant. For the most part, alpacas are very quiet, but male alpacas are more energetic when they get involved in fighting with other alpacas. When they prey, they are cautious but also nervous when they feel any type of threat. They can feel threatened when a person or another alpaca comes up from behind them.

Alpacas set their own boundaries of "personal space" within their families and groups.They make a hierarchy in some sense, and each alpaca is aware of the dominant animals in each group. Body language is the key to their communication. It helps to maintain their order. One example of their body communication includes a pose named broadside, where their ears are pulled back and they stand sideways. This pose is used when male alpacas are defending their territory.

When they are young, they tend to follow larger objects and to sit near or under them. An example of this is a baby alpaca with its mother. This can also apply when an alpaca passes by an older alpaca.

Training
Alpacas are generally very trainable and usually respond to reward, most commonly in the form of food. They can usually be petted without getting agitated, especially if one avoids petting the head or neck. Alpacas are usually quite easy to herd, even in large groups. However, during herding, it is recommended for the handler to approach the animals slowly and quietly, as failing to do so can result in danger for both the animals and the handler.

Alpacas and llamas have started showing up in U.S. nursing homes and hospitals as trained, certified therapy animals. The Mayo Clinic says animal-assisted therapy can reduce pain, depression, anxiety, and fatigue. This type of animal therapy is growing in popularity, and there are several organizations throughout the United States that participate.

Spitting
Not all alpacas spit, but all are capable of doing so. "Spit" is somewhat euphemistic; occasionally the projectile contains only air and a little saliva, although alpacas commonly bring up acidic stomach contents (generally a green, grassy mix) and project it onto their chosen targets. Spitting is mostly reserved for other alpacas, but an alpaca will also occasionally spit at a human.

Spitting can result in what is called "sour mouth". Sour mouth is characterized by "a loose-hanging lower lip and a gaping mouth."

Alpacas can spit for several reasons. A female alpaca spits when she is not interested in a male alpaca, typically when she thinks that she is already impregnated. Both sexes of alpaca keep others away from their food, or anything they have their eyes on. Most give a slight warning before spitting by blowing air out and raising their heads, giving their ears a "pinned" appearance.

Alpacas can spit up to ten feet if they need to. For example, if another animal does not back off, the alpaca will throw up its stomach contents, resulting in a lot of spit.

Some signs of stress which can lead to their spitting habits include: humming, a wrinkle under their eye, drooling, rapid breathing, and stomping their feet. When alpacas show any sign of interest or alertness, they tend to sniff their surroundings, watch closely, or stand quietly in place and stare.

When it comes to reproduction, they spit because it is a response triggered by the progesterone levels being increased, which is associated with ovulation.

Hygiene
Alpacas use a communal dung pile, where they do not graze. This behaviour tends to limit the spread of internal parasites. Generally, males have much tidier, and fewer dung piles than females, which tend to stand in a line and all go at once. One female approaches the dung pile and begins to urinate and/or defecate, and the rest of the herd often follows. Alpaca waste is collected and used as garden fertilizer or even natural fertilizer.

Because of their preference for using a dung pile for excreting bodily waste, some alpacas have been successfully house-trained.

Alpacas develop dental hygiene problems which affect their eating and behavior. Warning signs include protracted chewing while eating, or food spilling out of their mouths. Poor body condition and sunken cheeks are also telltales of dental problems.

Alpacas make a variety of sounds:

Humming: When alpacas are born, the mother and baby hum constantly. They also hum as a sign of distress, especially when they are separated from their herd. Alpacas may also hum when curious, happy, worried or cautious.
Snorting: Alpacas snort when another alpaca is invading its space.
Grumbling: Alpacas grumble to warn each other. For example, when one is invading another's personal space, it sounds like gurgling.
Clucking: Similar to a hen's cluck, alpacas cluck when a mother is concerned for her cria. Male alpacas cluck to signal friendly behavior.
Screaming: Their screams are extremely deafening and loud. They will scream when they are not handled correctly or when they are being attacked by a potential enemy.
Screeching: A bird-like cry, presumably intended to terrify the opponent. This sound is typically used by male alpacas when they are in a fight over dominance. When a female screeches, it is more of a growl when she is angry.

Reproduction
Females are induced ovulators; meaning the act of mating and the presence of semen causes them to ovulate. Females usually conceive after just one breeding, but occasionally do have trouble conceiving. Artificial insemination is technically difficult, expensive and not common, but it can be accomplished. Embryo transfer is more widespread.

A male is usually ready to mate for the first time between two and three years of age. It is not advisable to allow a young female to be bred until she is mature and has reached two-thirds of her mature weight. Over-breeding a young female before conception is possibly a common cause of uterine infections. As the age of maturation varies greatly between individuals, it is usually recommended that novice breeders wait until females are 18 months of age or older before initiating breeding.

Alpacas can breed at any time throughout the year but it is more difficult to breed in the winter. Most breed during autumn or late spring. The most popular way to have alpacas mate is pen mating. Pen mating is when they move both the female and the desired male into a pen. Another way is paddock mating where one male alpaca is let loose in the paddock with several female alpacas.

The gestation period is, on average, 11.5 months, and usually results in a single offspring, or cria. Twins are rare, occurring about once per 1000 deliveries. Cria are generally between 15 and 19 pounds, and are standing 30 to 90 minutes after birth. After a female gives birth, she is generally receptive to breeding again after about two weeks. Crias may be weaned through human intervention at about six months old and 60 pounds, but many breeders prefer to allow the female to decide when to wean her offspring; they can be weaned earlier or later depending on their size and emotional maturity.

The average lifespan of an alpaca is between 15 and 20 years, and the longest-lived alpaca on record is 27 years.


Pests and diseases
Cattle tuberculosis can also infect alpacas: Mycobacterium bovis also causes TB in this species worldwide. Krajewska‐Wędzina et al., 2020 detect M. bovis in individuals traded from the United Kingdom to Poland. To accomplish this they develop a seroassay which correctly identifies positive subjects which are false negative for a common skin test. Krajewska‐Wędzina et al. also find that alpacas are unusual in mounting a competent early-infection immune response. Bernitz et al., 2021 believe this to generalise to all camelids.

Habitat and lifestyle
Alpacas can be found throughout most of South America. They typically live in temperate conditions in the mountains with high altitudes.

They are easy to care for since they are not limited to a specific type of environment. Animals such as flamingos, condors, spectacled bears, mountain lions, coyotes, llamas, and sheep live near alpacas when they are in their natural habitat.

Population
Alpacas are native to Peru, but can be found throughout the globe in captivity. Peru currently has the largest alpaca population, with over half the world's animals. The population declined drastically after the Spanish Conquistadors invaded the Andes mountains in 1532, after which 98% of the animals were destroyed. The Spanish also brought with them diseases that were fatal to alpacas.

European conquest forced the animals to move higher into the mountains, which remained there permanently. Although alpacas had almost been wiped out completely, they were rediscovered sometime during the 19th century by Europeans. After finding uses for them, the animals became important to societies during the industrial revolution.

In popular culture
Nuzzle and Scratch was a British children's television programme featuring two fictional alpacas that was first broadcast between 2008 and 2011.

Interest in alpacas grew as a result of Depp v. Heard, the 2022 trial in which Johnny Depp sued Amber Heard for defamation in Virginia after Heard wrote an op-ed saying she was a public victim of domestic violence. Depp testified, under oath, that he would not make another Pirates of the Caribbean film for "300 million dollars and a million alpacas".

Diet

Alpacas chew their food which ends up being mixed with their cud and saliva and then they swallow it. Alpacas usually eat 1.5% of their body weight daily for normal growth. They mainly need pasture grass, hay, or silage but some may also need supplemental energy and protein foods and they will also normally try to chew on almost anything (e.g. empty bottle). Most alpaca ranchers rotate their feeding grounds so the grass can regrow and fecal parasites may die before reusing the area. Pasture grass is a great source of protein. When seasons change, the grass loses or gains more protein. For example, in the spring, the pasture grass has about 20% protein while in the summer, it only has 6%. They need more energy supplements in the winter to produce body heat and warmth. They get their fiber from hay or from long stems which provides them with vitamin E. Green grass contains vitamin A and E.

Alpacas can eat natural unfertilized grass; however, ranchers can also supplement grass with low-protein grass hay. To provide selenium and other necessary vitamins, ranchers will feed their domestic alpacas a daily dose of grain to provide additional nutrients that are not fully obtained from their primary diet. Alpacas may obtain the necessary vitamins in their native grazing ranges.

Digestion
Alpacas, like other camelids, have a three-chambered stomach; combined with chewing cud, this three-chambered system allows maximum extraction of nutrients from low-quality forages. Alpacas are not ruminants, pseudo-ruminants, or modified ruminants, as there are many differences between the anatomy and physiology of a camelid and a ruminant stomach.

Alpacas will chew their food in a figure eight motion, swallow the food, and then pass it into one of the stomach's chambers. The first and second chambers (called C1 and C2) are anaerobic fermentation chambers where the fermentation process begins. The alpaca will further absorb nutrients and water in the first part of the third chamber. The end of the third chamber (called C3) is where the stomach secretes acids to digest food and is the likely place where an alpaca will have ulcers if stressed.

Poisonous plants
Many plants are poisonous to the alpaca, including the bracken fern, Madagascar ragwort, oleander, and some azaleas. In common with similar livestock, others include acorns, African rue, agave, amaryllis, autumn crocus, bear grass, broom snakeweed, buckwheat, ragweed, buttercups, calla lily, orange tree foliage, carnations, castor beans, and many others.

Fiber
Main article: Alpaca fiber
Alpacas are typically sheared once per year in the spring. Each shearing produces approximately 2.3 to 4.5 kilograms (5 to 10 pounds) of fiber per alpaca. An adult alpaca might produce 1.4 to 2.6 kilograms (50 to 90 ounces) of first-quality fiber as well as 1.4 to 2.8 kilograms (50 to 100 ounces) of second- and third-quality fiber. The quality of alpaca fiber is determined by how crimpy it is. Typically, the greater the number of small folds in the fiber, the greater the quality.

Prices
Alpacas were the subject of a speculative bubble between their introduction to North America in 1984 and the early 21st century. The price for American alpacas ranged from US$50 for a castrated male (gelding) to US$675,000 for the highest in the world, depending on breeding history, sex, and color. In 2006, researchers warned that the higher prices sought for alpaca breeding stock were largely speculative and not supported by market fundamentals, given the low inherent returns per head from the main end product, alpaca fiber, and prices into the $100s per head rather than $10,000s would be required for a commercially viable fiber production herd.

Marketed as "the investment you can hug" in television commercials by the Alpaca Owners and Breeders Association, the market for alpacas was almost entirely dependent on breeding and selling animals to new buyers, a classic sign of speculative bubbles in livestock. The bubble burst in 2007, with the price of alpaca breeding stock dropping by thousands of dollars each year thereafter. Many farmers found themselves unable to sell animals for any price, or even give them away.

It is possible to raise up to 25 alpacas per hectare (10/acre), as they have a designated area for waste products and keep their eating area away from their waste area. However, this ratio differs from country to country and is highly dependent on the quality of pasture available (in many desert locations it is generally only possible to run one to three animals per acre due to lack of suitable vegetation). Fiber quality is the primary variant in the price achieved for alpaca wool; in Australia, it is common to classify the fiber by the thickness of the individual hairs and by the amount of vegetable matter contained in the supplied shearings.

Livestock

Alpacas need to eat 1–2% of their body weight per day, so about two 27 kg (60 lb) bales of grass hay per month per animal. When formulating a proper diet for alpacas, water and hay analysis should be performed to determine the proper vitamin and mineral supplementation program. Two options are to provide free choice salt/mineral powder or feed a specially formulated ration. Indigenous to the highest regions of the Andes, this harsh environment has created an extremely hardy animal, so only minimal housing and predator fencing are needed. The alpacas' three-chambered stomachs allow for extremely efficient digestion. There are no viable seeds in the manure, because alpacas prefer to only eat tender plant leaves, and will not consume thick plant stems; therefore, alpaca manure does not need composting to enrich pastures or ornamental landscaping. Nail and teeth trimming are needed every six to twelve months, along with annual shearing.

Similar to ruminants, such as cattle and sheep, alpacas have only lower teeth at the front of their mouths; therefore, they do not pull the grass up by the roots. Rotating pastures is still important, though, as alpacas have a tendency to regraze an area repeatedly. Alpacas are fiber-producing animals; they do not need to be slaughtered to reap their product, and their fiber is a renewable resource that grows yearly.

Cultural presence

Alpacas are closely tied to cultural practices for Andeans people. Prior to colonization, the image of the alpaca was used in rituals and in their religious practices. Since the people in the region depended heavily on these animals for their sustenance, the alpaca was seen as a gift from Pachamama. Alpacas were used for their meat, fibers for clothing, and art, and their images in the form of conopas.

Conopas take their appearance from the Suri alpacas, with long locks flanking their sides and bangs covering the eyes, and a depression on the back. This depression is used in ritual practices, usually filled with coca leaves and fat from alpacas and lamas, to bring fertility and luck. While their use was prevalent before colonization, the attempts to convert the Andean people to Catholicism led to the acquisition of more than 3,400 conopas in Lima alone.

The origin of alpacas is depicted in legend; the legend states they came to be in the world after a goddess fell in love with a man. The goddess' father only allowed her to be with her lover if he cared for her herd of alpacas. On top of caring for the herd, he was to always carry a small animal for his entire life. As the goddess came into our world, the alpacas followed her. Everything was fine until the man set the small animal down, and the goddess fled back to her home. On her way back home, the man attempted to stop her and her herd from fleeing. While he was not able to stop her from returning, he was able to stop a few alpacas from returning. These alpacas who did not make it back are said to be seen today in the swampy lands in the Andes waiting for the end of the world, so they may return to their goddess.

Alpaca (Vicugna Pacos) by millicand@rocketmail.com

© millicand@rocketmail.com, all rights reserved.

Alpaca (Vicugna Pacos)

The alpaca (Lama pacos) is a species of South American camelid mammal. It is similar to, and often confused with, the llama. However, alpacas are often noticeably smaller than llamas. The two animals are closely related and can successfully crossbreed. Both species are believed to have been domesticated from their wild relatives, the vicuña and guanaco. There are two breeds of alpaca: the Suri alpaca and the Huacaya alpaca.

Alpacas are kept in herds that graze on the level heights of the Andes of Southern Peru, Western Bolivia, Ecuador, and Northern Chile at an altitude of 3,500 to 5,000 metres (11,000 to 16,000 feet) above sea level. Alpacas are considerably smaller than llamas, and unlike llamas, they were not bred to be working animals, but were bred specifically for their fiber. Alpaca fiber is used for making knitted and woven items, similar to sheep's wool. These items include blankets, sweaters, hats, gloves, scarves, a wide variety of textiles, and ponchos, in South America, as well as sweaters, socks, coats, and bedding in other parts of the world. The fiber comes in more than 52 natural colors as classified in Peru, 12 as classified in Australia, and 16 as classified in the United States.

Alpacas communicate through body language. The most common is spitting to show dominance when they are in distress, fearful, or feel agitated. Male alpacas are more aggressive than females, and tend to establish dominance within their herd group. In some cases, alpha males will immobilize the head and neck of a weaker or challenging male in order to show their strength and dominance.

In the textile industry, "alpaca" primarily refers to the hair of Peruvian alpacas, but more broadly it refers to a style of fabric originally made from alpaca hair, such as mohair, Icelandic sheep wool, or even high-quality wool from other breeds of sheep. In trade, distinctions are made between alpacas and the several styles of mohair and luster.

An adult alpaca generally is between 81 and 99 centimetres (32 and 39 inches) in height at the shoulders (withers). They usually weigh between 48 and 90 kilograms (106 and 198 pounds). Raised in the same conditions, the difference in weight can be small with males weighting around 22.3 kilograms (49 lb 3 oz) and females 21.3 kilograms (46 lb 15 oz).

Background

The relationship between alpacas and vicuñas was disputed for many years. In the 18th and 19th centuries, the four South American lamoid species were assigned scientific names. At that time, the alpaca was assumed to be descended from the llama, ignoring similarities in size, fleece and dentition between the alpaca and the vicuña. Classification was complicated by the fact that all four species of South American camelid can interbreed and produce fertile offspring. The advent of DNA technology made a more accurate classification possible.

In 2001, the alpaca genus classification changed from Lama pacos to Vicugna pacos, following the presentation of a paper on work by Miranda Kadwell et al. on alpaca DNA to the Royal Society showing the alpaca is descended from the vicuña, not the guanaco.

Origin and domestication
Alpacas were domesticated thousands of years ago. The Moche people of Northern Peru often used alpaca images in their art. There are no known wild alpacas, and its closest living relative, the vicuña (also native to South America), is the wild ancestor of the alpaca.

The family Camelidae first appeared in Americas 40–45 million years ago, during the Eocene period, from the common ancestor, Protylopus. The descendants divided into Camelini and Lamini tribes, taking different migratory patterns to Asia and South America, respectively. Although the camelids became extinct in North America around 3 million years ago, it flourished in the South with the species we see today. It was not until 2–5 million years ago, during the Pliocene, that the genus Hemiauchenia of the tribe Lamini split into Palaeolama and Lama; the latter would then split again into Lama and Vicugna upon migrating down to South America.

Remains of vicuña and guanaco dating around 12,000 years have been found throughout Peru. Their domesticated counterparts, the llama and alpaca, have been found mummified in the Moquegua valley, in the south of Peru, dating back 900 to 1000 years. Mummies found in this region show two breeds of alpacas. More precise analysis of bone and teeth of these mummies has demonstrated that alpacas were domesticated from the Vicugna vicugna. Other research, considering the behavioral and morphological characteristics of alpacas and their wild counterparts, seems to indicate that alpacas could find their origins in Lama guanicoe as well as Vicugna vicugna, or even a hybrid of both.

Genetic analysis shows a different picture of the origins of the alpaca. Analysis of mitochondrial DNA shows that most alpacas have guanaco mtDNA, and many also have vicuña mtDNA. But microsatellite data shows that alpaca DNA is much more similar to vicuña DNA than to guanaco DNA. This suggests that alpacas are descendants of the Vicugna vicugna, not of the Lama guanicoe. The discrepancy with mtDNA seems to be a result of the fact that mtDNA is only transmitted by the mother, and recent husbandry practices have caused hybridization between llamas (which primarily carry guanaco DNA) and alpacas. To the extent that many of today's domestic alpacas are the result of male alpacas bred to female llamas, this would explain the mtDNA consistent with guanacos. This situation has led to attempts to reclassify the alpaca as Vicugna pacos.

Breeds
The alpaca comes in two breeds, Suri and Huacaya, based on their fibers rather than scientific or European classifications.
(Museum of Osteology)
Huacaya alpacas are the most commonly found, constituting about 90% of the population. The Huacaya alpaca is thought to have originated in post-colonial Peru. This is due to their thicker fleece which makes them more suited to survive in the higher altitudes of the Andes after being pushed into the highlands of Peru with the arrival of the Spanish.

Suri alpacas represent a smaller portion of the total alpaca population, around 10%. They are thought to have been more prevalent in pre-Columbian Peru since they could be kept at a lower altitude where a thicker fleece was not needed for harsh weather conditions.

Behavior

Alpacas are social herd animals that live in family groups, consisting of a territorial alpha male, females, and their young ones. Alpacas warn the herd about intruders by making sharp, noisy inhalations that sound like a high-pitched bray. The herd may attack smaller predators with their front feet and can spit and kick. Their aggression towards members of the canid family (coyotes, foxes, dogs etc.) is exploited when alpacas are used as guard llamas for guarding sheep.

Alpacas can sometimes be aggressive, but they can also be very gentle, intelligent, and extremely observant. For the most part, alpacas are very quiet, but male alpacas are more energetic when they get involved in fighting with other alpacas. When they prey, they are cautious but also nervous when they feel any type of threat. They can feel threatened when a person or another alpaca comes up from behind them.

Alpacas set their own boundaries of "personal space" within their families and groups.They make a hierarchy in some sense, and each alpaca is aware of the dominant animals in each group. Body language is the key to their communication. It helps to maintain their order. One example of their body communication includes a pose named broadside, where their ears are pulled back and they stand sideways. This pose is used when male alpacas are defending their territory.

When they are young, they tend to follow larger objects and to sit near or under them. An example of this is a baby alpaca with its mother. This can also apply when an alpaca passes by an older alpaca.

Training
Alpacas are generally very trainable and usually respond to reward, most commonly in the form of food. They can usually be petted without getting agitated, especially if one avoids petting the head or neck. Alpacas are usually quite easy to herd, even in large groups. However, during herding, it is recommended for the handler to approach the animals slowly and quietly, as failing to do so can result in danger for both the animals and the handler.

Alpacas and llamas have started showing up in U.S. nursing homes and hospitals as trained, certified therapy animals. The Mayo Clinic says animal-assisted therapy can reduce pain, depression, anxiety, and fatigue. This type of animal therapy is growing in popularity, and there are several organizations throughout the United States that participate.

Spitting
Not all alpacas spit, but all are capable of doing so. "Spit" is somewhat euphemistic; occasionally the projectile contains only air and a little saliva, although alpacas commonly bring up acidic stomach contents (generally a green, grassy mix) and project it onto their chosen targets. Spitting is mostly reserved for other alpacas, but an alpaca will also occasionally spit at a human.

Spitting can result in what is called "sour mouth". Sour mouth is characterized by "a loose-hanging lower lip and a gaping mouth."

Alpacas can spit for several reasons. A female alpaca spits when she is not interested in a male alpaca, typically when she thinks that she is already impregnated. Both sexes of alpaca keep others away from their food, or anything they have their eyes on. Most give a slight warning before spitting by blowing air out and raising their heads, giving their ears a "pinned" appearance.

Alpacas can spit up to ten feet if they need to. For example, if another animal does not back off, the alpaca will throw up its stomach contents, resulting in a lot of spit.

Some signs of stress which can lead to their spitting habits include: humming, a wrinkle under their eye, drooling, rapid breathing, and stomping their feet. When alpacas show any sign of interest or alertness, they tend to sniff their surroundings, watch closely, or stand quietly in place and stare.

When it comes to reproduction, they spit because it is a response triggered by the progesterone levels being increased, which is associated with ovulation.

Hygiene
Alpacas use a communal dung pile, where they do not graze. This behaviour tends to limit the spread of internal parasites. Generally, males have much tidier, and fewer dung piles than females, which tend to stand in a line and all go at once. One female approaches the dung pile and begins to urinate and/or defecate, and the rest of the herd often follows. Alpaca waste is collected and used as garden fertilizer or even natural fertilizer.

Because of their preference for using a dung pile for excreting bodily waste, some alpacas have been successfully house-trained.

Alpacas develop dental hygiene problems which affect their eating and behavior. Warning signs include protracted chewing while eating, or food spilling out of their mouths. Poor body condition and sunken cheeks are also telltales of dental problems.

Alpacas make a variety of sounds:

Humming: When alpacas are born, the mother and baby hum constantly. They also hum as a sign of distress, especially when they are separated from their herd. Alpacas may also hum when curious, happy, worried or cautious.
Snorting: Alpacas snort when another alpaca is invading its space.
Grumbling: Alpacas grumble to warn each other. For example, when one is invading another's personal space, it sounds like gurgling.
Clucking: Similar to a hen's cluck, alpacas cluck when a mother is concerned for her cria. Male alpacas cluck to signal friendly behavior.
Screaming: Their screams are extremely deafening and loud. They will scream when they are not handled correctly or when they are being attacked by a potential enemy.
Screeching: A bird-like cry, presumably intended to terrify the opponent. This sound is typically used by male alpacas when they are in a fight over dominance. When a female screeches, it is more of a growl when she is angry.

Reproduction
Females are induced ovulators; meaning the act of mating and the presence of semen causes them to ovulate. Females usually conceive after just one breeding, but occasionally do have trouble conceiving. Artificial insemination is technically difficult, expensive and not common, but it can be accomplished. Embryo transfer is more widespread.

A male is usually ready to mate for the first time between two and three years of age. It is not advisable to allow a young female to be bred until she is mature and has reached two-thirds of her mature weight. Over-breeding a young female before conception is possibly a common cause of uterine infections. As the age of maturation varies greatly between individuals, it is usually recommended that novice breeders wait until females are 18 months of age or older before initiating breeding.

Alpacas can breed at any time throughout the year but it is more difficult to breed in the winter. Most breed during autumn or late spring. The most popular way to have alpacas mate is pen mating. Pen mating is when they move both the female and the desired male into a pen. Another way is paddock mating where one male alpaca is let loose in the paddock with several female alpacas.

The gestation period is, on average, 11.5 months, and usually results in a single offspring, or cria. Twins are rare, occurring about once per 1000 deliveries. Cria are generally between 15 and 19 pounds, and are standing 30 to 90 minutes after birth. After a female gives birth, she is generally receptive to breeding again after about two weeks. Crias may be weaned through human intervention at about six months old and 60 pounds, but many breeders prefer to allow the female to decide when to wean her offspring; they can be weaned earlier or later depending on their size and emotional maturity.

The average lifespan of an alpaca is between 15 and 20 years, and the longest-lived alpaca on record is 27 years.


Pests and diseases
Cattle tuberculosis can also infect alpacas: Mycobacterium bovis also causes TB in this species worldwide. Krajewska‐Wędzina et al., 2020 detect M. bovis in individuals traded from the United Kingdom to Poland. To accomplish this they develop a seroassay which correctly identifies positive subjects which are false negative for a common skin test. Krajewska‐Wędzina et al. also find that alpacas are unusual in mounting a competent early-infection immune response. Bernitz et al., 2021 believe this to generalise to all camelids.

Habitat and lifestyle
Alpacas can be found throughout most of South America. They typically live in temperate conditions in the mountains with high altitudes.

They are easy to care for since they are not limited to a specific type of environment. Animals such as flamingos, condors, spectacled bears, mountain lions, coyotes, llamas, and sheep live near alpacas when they are in their natural habitat.

Population
Alpacas are native to Peru, but can be found throughout the globe in captivity. Peru currently has the largest alpaca population, with over half the world's animals. The population declined drastically after the Spanish Conquistadors invaded the Andes mountains in 1532, after which 98% of the animals were destroyed. The Spanish also brought with them diseases that were fatal to alpacas.

European conquest forced the animals to move higher into the mountains, which remained there permanently. Although alpacas had almost been wiped out completely, they were rediscovered sometime during the 19th century by Europeans. After finding uses for them, the animals became important to societies during the industrial revolution.

In popular culture
Nuzzle and Scratch was a British children's television programme featuring two fictional alpacas that was first broadcast between 2008 and 2011.

Interest in alpacas grew as a result of Depp v. Heard, the 2022 trial in which Johnny Depp sued Amber Heard for defamation in Virginia after Heard wrote an op-ed saying she was a public victim of domestic violence. Depp testified, under oath, that he would not make another Pirates of the Caribbean film for "300 million dollars and a million alpacas".

Diet

Alpacas chew their food which ends up being mixed with their cud and saliva and then they swallow it. Alpacas usually eat 1.5% of their body weight daily for normal growth. They mainly need pasture grass, hay, or silage but some may also need supplemental energy and protein foods and they will also normally try to chew on almost anything (e.g. empty bottle). Most alpaca ranchers rotate their feeding grounds so the grass can regrow and fecal parasites may die before reusing the area. Pasture grass is a great source of protein. When seasons change, the grass loses or gains more protein. For example, in the spring, the pasture grass has about 20% protein while in the summer, it only has 6%. They need more energy supplements in the winter to produce body heat and warmth. They get their fiber from hay or from long stems which provides them with vitamin E. Green grass contains vitamin A and E.

Alpacas can eat natural unfertilized grass; however, ranchers can also supplement grass with low-protein grass hay. To provide selenium and other necessary vitamins, ranchers will feed their domestic alpacas a daily dose of grain to provide additional nutrients that are not fully obtained from their primary diet. Alpacas may obtain the necessary vitamins in their native grazing ranges.

Digestion
Alpacas, like other camelids, have a three-chambered stomach; combined with chewing cud, this three-chambered system allows maximum extraction of nutrients from low-quality forages. Alpacas are not ruminants, pseudo-ruminants, or modified ruminants, as there are many differences between the anatomy and physiology of a camelid and a ruminant stomach.

Alpacas will chew their food in a figure eight motion, swallow the food, and then pass it into one of the stomach's chambers. The first and second chambers (called C1 and C2) are anaerobic fermentation chambers where the fermentation process begins. The alpaca will further absorb nutrients and water in the first part of the third chamber. The end of the third chamber (called C3) is where the stomach secretes acids to digest food and is the likely place where an alpaca will have ulcers if stressed.

Poisonous plants
Many plants are poisonous to the alpaca, including the bracken fern, Madagascar ragwort, oleander, and some azaleas. In common with similar livestock, others include acorns, African rue, agave, amaryllis, autumn crocus, bear grass, broom snakeweed, buckwheat, ragweed, buttercups, calla lily, orange tree foliage, carnations, castor beans, and many others.

Fiber
Main article: Alpaca fiber
Alpacas are typically sheared once per year in the spring. Each shearing produces approximately 2.3 to 4.5 kilograms (5 to 10 pounds) of fiber per alpaca. An adult alpaca might produce 1.4 to 2.6 kilograms (50 to 90 ounces) of first-quality fiber as well as 1.4 to 2.8 kilograms (50 to 100 ounces) of second- and third-quality fiber. The quality of alpaca fiber is determined by how crimpy it is. Typically, the greater the number of small folds in the fiber, the greater the quality.

Prices
Alpacas were the subject of a speculative bubble between their introduction to North America in 1984 and the early 21st century. The price for American alpacas ranged from US$50 for a castrated male (gelding) to US$675,000 for the highest in the world, depending on breeding history, sex, and color. In 2006, researchers warned that the higher prices sought for alpaca breeding stock were largely speculative and not supported by market fundamentals, given the low inherent returns per head from the main end product, alpaca fiber, and prices into the $100s per head rather than $10,000s would be required for a commercially viable fiber production herd.

Marketed as "the investment you can hug" in television commercials by the Alpaca Owners and Breeders Association, the market for alpacas was almost entirely dependent on breeding and selling animals to new buyers, a classic sign of speculative bubbles in livestock. The bubble burst in 2007, with the price of alpaca breeding stock dropping by thousands of dollars each year thereafter. Many farmers found themselves unable to sell animals for any price, or even give them away.

It is possible to raise up to 25 alpacas per hectare (10/acre), as they have a designated area for waste products and keep their eating area away from their waste area. However, this ratio differs from country to country and is highly dependent on the quality of pasture available (in many desert locations it is generally only possible to run one to three animals per acre due to lack of suitable vegetation). Fiber quality is the primary variant in the price achieved for alpaca wool; in Australia, it is common to classify the fiber by the thickness of the individual hairs and by the amount of vegetable matter contained in the supplied shearings.

Livestock

Alpacas need to eat 1–2% of their body weight per day, so about two 27 kg (60 lb) bales of grass hay per month per animal. When formulating a proper diet for alpacas, water and hay analysis should be performed to determine the proper vitamin and mineral supplementation program. Two options are to provide free choice salt/mineral powder or feed a specially formulated ration. Indigenous to the highest regions of the Andes, this harsh environment has created an extremely hardy animal, so only minimal housing and predator fencing are needed. The alpacas' three-chambered stomachs allow for extremely efficient digestion. There are no viable seeds in the manure, because alpacas prefer to only eat tender plant leaves, and will not consume thick plant stems; therefore, alpaca manure does not need composting to enrich pastures or ornamental landscaping. Nail and teeth trimming are needed every six to twelve months, along with annual shearing.

Similar to ruminants, such as cattle and sheep, alpacas have only lower teeth at the front of their mouths; therefore, they do not pull the grass up by the roots. Rotating pastures is still important, though, as alpacas have a tendency to regraze an area repeatedly. Alpacas are fiber-producing animals; they do not need to be slaughtered to reap their product, and their fiber is a renewable resource that grows yearly.

Cultural presence

Alpacas are closely tied to cultural practices for Andeans people. Prior to colonization, the image of the alpaca was used in rituals and in their religious practices. Since the people in the region depended heavily on these animals for their sustenance, the alpaca was seen as a gift from Pachamama. Alpacas were used for their meat, fibers for clothing, and art, and their images in the form of conopas.

Conopas take their appearance from the Suri alpacas, with long locks flanking their sides and bangs covering the eyes, and a depression on the back. This depression is used in ritual practices, usually filled with coca leaves and fat from alpacas and lamas, to bring fertility and luck. While their use was prevalent before colonization, the attempts to convert the Andean people to Catholicism led to the acquisition of more than 3,400 conopas in Lima alone.

The origin of alpacas is depicted in legend; the legend states they came to be in the world after a goddess fell in love with a man. The goddess' father only allowed her to be with her lover if he cared for her herd of alpacas. On top of caring for the herd, he was to always carry a small animal for his entire life. As the goddess came into our world, the alpacas followed her. Everything was fine until the man set the small animal down, and the goddess fled back to her home. On her way back home, the man attempted to stop her and her herd from fleeing. While he was not able to stop her from returning, he was able to stop a few alpacas from returning. These alpacas who did not make it back are said to be seen today in the swampy lands in the Andes waiting for the end of the world, so they may return to their goddess.

Alpaca (Vicugna Pacos) by millicand@rocketmail.com

© millicand@rocketmail.com, all rights reserved.

Alpaca (Vicugna Pacos)

The alpaca (Lama pacos) is a species of South American camelid mammal. It is similar to, and often confused with, the llama. However, alpacas are often noticeably smaller than llamas. The two animals are closely related and can successfully crossbreed. Both species are believed to have been domesticated from their wild relatives, the vicuña and guanaco. There are two breeds of alpaca: the Suri alpaca and the Huacaya alpaca.

Alpacas are kept in herds that graze on the level heights of the Andes of Southern Peru, Western Bolivia, Ecuador, and Northern Chile at an altitude of 3,500 to 5,000 metres (11,000 to 16,000 feet) above sea level. Alpacas are considerably smaller than llamas, and unlike llamas, they were not bred to be working animals, but were bred specifically for their fiber. Alpaca fiber is used for making knitted and woven items, similar to sheep's wool. These items include blankets, sweaters, hats, gloves, scarves, a wide variety of textiles, and ponchos, in South America, as well as sweaters, socks, coats, and bedding in other parts of the world. The fiber comes in more than 52 natural colors as classified in Peru, 12 as classified in Australia, and 16 as classified in the United States.

Alpacas communicate through body language. The most common is spitting to show dominance when they are in distress, fearful, or feel agitated. Male alpacas are more aggressive than females, and tend to establish dominance within their herd group. In some cases, alpha males will immobilize the head and neck of a weaker or challenging male in order to show their strength and dominance.

In the textile industry, "alpaca" primarily refers to the hair of Peruvian alpacas, but more broadly it refers to a style of fabric originally made from alpaca hair, such as mohair, Icelandic sheep wool, or even high-quality wool from other breeds of sheep. In trade, distinctions are made between alpacas and the several styles of mohair and luster.

An adult alpaca generally is between 81 and 99 centimetres (32 and 39 inches) in height at the shoulders (withers). They usually weigh between 48 and 90 kilograms (106 and 198 pounds). Raised in the same conditions, the difference in weight can be small with males weighting around 22.3 kilograms (49 lb 3 oz) and females 21.3 kilograms (46 lb 15 oz).

Background

The relationship between alpacas and vicuñas was disputed for many years. In the 18th and 19th centuries, the four South American lamoid species were assigned scientific names. At that time, the alpaca was assumed to be descended from the llama, ignoring similarities in size, fleece and dentition between the alpaca and the vicuña. Classification was complicated by the fact that all four species of South American camelid can interbreed and produce fertile offspring. The advent of DNA technology made a more accurate classification possible.

In 2001, the alpaca genus classification changed from Lama pacos to Vicugna pacos, following the presentation of a paper on work by Miranda Kadwell et al. on alpaca DNA to the Royal Society showing the alpaca is descended from the vicuña, not the guanaco.

Origin and domestication
Alpacas were domesticated thousands of years ago. The Moche people of Northern Peru often used alpaca images in their art. There are no known wild alpacas, and its closest living relative, the vicuña (also native to South America), is the wild ancestor of the alpaca.

The family Camelidae first appeared in Americas 40–45 million years ago, during the Eocene period, from the common ancestor, Protylopus. The descendants divided into Camelini and Lamini tribes, taking different migratory patterns to Asia and South America, respectively. Although the camelids became extinct in North America around 3 million years ago, it flourished in the South with the species we see today. It was not until 2–5 million years ago, during the Pliocene, that the genus Hemiauchenia of the tribe Lamini split into Palaeolama and Lama; the latter would then split again into Lama and Vicugna upon migrating down to South America.

Remains of vicuña and guanaco dating around 12,000 years have been found throughout Peru. Their domesticated counterparts, the llama and alpaca, have been found mummified in the Moquegua valley, in the south of Peru, dating back 900 to 1000 years. Mummies found in this region show two breeds of alpacas. More precise analysis of bone and teeth of these mummies has demonstrated that alpacas were domesticated from the Vicugna vicugna. Other research, considering the behavioral and morphological characteristics of alpacas and their wild counterparts, seems to indicate that alpacas could find their origins in Lama guanicoe as well as Vicugna vicugna, or even a hybrid of both.

Genetic analysis shows a different picture of the origins of the alpaca. Analysis of mitochondrial DNA shows that most alpacas have guanaco mtDNA, and many also have vicuña mtDNA. But microsatellite data shows that alpaca DNA is much more similar to vicuña DNA than to guanaco DNA. This suggests that alpacas are descendants of the Vicugna vicugna, not of the Lama guanicoe. The discrepancy with mtDNA seems to be a result of the fact that mtDNA is only transmitted by the mother, and recent husbandry practices have caused hybridization between llamas (which primarily carry guanaco DNA) and alpacas. To the extent that many of today's domestic alpacas are the result of male alpacas bred to female llamas, this would explain the mtDNA consistent with guanacos. This situation has led to attempts to reclassify the alpaca as Vicugna pacos.

Breeds
The alpaca comes in two breeds, Suri and Huacaya, based on their fibers rather than scientific or European classifications.
(Museum of Osteology)
Huacaya alpacas are the most commonly found, constituting about 90% of the population. The Huacaya alpaca is thought to have originated in post-colonial Peru. This is due to their thicker fleece which makes them more suited to survive in the higher altitudes of the Andes after being pushed into the highlands of Peru with the arrival of the Spanish.

Suri alpacas represent a smaller portion of the total alpaca population, around 10%. They are thought to have been more prevalent in pre-Columbian Peru since they could be kept at a lower altitude where a thicker fleece was not needed for harsh weather conditions.

Behavior

Alpacas are social herd animals that live in family groups, consisting of a territorial alpha male, females, and their young ones. Alpacas warn the herd about intruders by making sharp, noisy inhalations that sound like a high-pitched bray. The herd may attack smaller predators with their front feet and can spit and kick. Their aggression towards members of the canid family (coyotes, foxes, dogs etc.) is exploited when alpacas are used as guard llamas for guarding sheep.

Alpacas can sometimes be aggressive, but they can also be very gentle, intelligent, and extremely observant. For the most part, alpacas are very quiet, but male alpacas are more energetic when they get involved in fighting with other alpacas. When they prey, they are cautious but also nervous when they feel any type of threat. They can feel threatened when a person or another alpaca comes up from behind them.

Alpacas set their own boundaries of "personal space" within their families and groups.They make a hierarchy in some sense, and each alpaca is aware of the dominant animals in each group. Body language is the key to their communication. It helps to maintain their order. One example of their body communication includes a pose named broadside, where their ears are pulled back and they stand sideways. This pose is used when male alpacas are defending their territory.

When they are young, they tend to follow larger objects and to sit near or under them. An example of this is a baby alpaca with its mother. This can also apply when an alpaca passes by an older alpaca.

Training
Alpacas are generally very trainable and usually respond to reward, most commonly in the form of food. They can usually be petted without getting agitated, especially if one avoids petting the head or neck. Alpacas are usually quite easy to herd, even in large groups. However, during herding, it is recommended for the handler to approach the animals slowly and quietly, as failing to do so can result in danger for both the animals and the handler.

Alpacas and llamas have started showing up in U.S. nursing homes and hospitals as trained, certified therapy animals. The Mayo Clinic says animal-assisted therapy can reduce pain, depression, anxiety, and fatigue. This type of animal therapy is growing in popularity, and there are several organizations throughout the United States that participate.

Spitting
Not all alpacas spit, but all are capable of doing so. "Spit" is somewhat euphemistic; occasionally the projectile contains only air and a little saliva, although alpacas commonly bring up acidic stomach contents (generally a green, grassy mix) and project it onto their chosen targets. Spitting is mostly reserved for other alpacas, but an alpaca will also occasionally spit at a human.

Spitting can result in what is called "sour mouth". Sour mouth is characterized by "a loose-hanging lower lip and a gaping mouth."

Alpacas can spit for several reasons. A female alpaca spits when she is not interested in a male alpaca, typically when she thinks that she is already impregnated. Both sexes of alpaca keep others away from their food, or anything they have their eyes on. Most give a slight warning before spitting by blowing air out and raising their heads, giving their ears a "pinned" appearance.

Alpacas can spit up to ten feet if they need to. For example, if another animal does not back off, the alpaca will throw up its stomach contents, resulting in a lot of spit.

Some signs of stress which can lead to their spitting habits include: humming, a wrinkle under their eye, drooling, rapid breathing, and stomping their feet. When alpacas show any sign of interest or alertness, they tend to sniff their surroundings, watch closely, or stand quietly in place and stare.

When it comes to reproduction, they spit because it is a response triggered by the progesterone levels being increased, which is associated with ovulation.

Hygiene
Alpacas use a communal dung pile, where they do not graze. This behaviour tends to limit the spread of internal parasites. Generally, males have much tidier, and fewer dung piles than females, which tend to stand in a line and all go at once. One female approaches the dung pile and begins to urinate and/or defecate, and the rest of the herd often follows. Alpaca waste is collected and used as garden fertilizer or even natural fertilizer.

Because of their preference for using a dung pile for excreting bodily waste, some alpacas have been successfully house-trained.

Alpacas develop dental hygiene problems which affect their eating and behavior. Warning signs include protracted chewing while eating, or food spilling out of their mouths. Poor body condition and sunken cheeks are also telltales of dental problems.

Alpacas make a variety of sounds:

Humming: When alpacas are born, the mother and baby hum constantly. They also hum as a sign of distress, especially when they are separated from their herd. Alpacas may also hum when curious, happy, worried or cautious.
Snorting: Alpacas snort when another alpaca is invading its space.
Grumbling: Alpacas grumble to warn each other. For example, when one is invading another's personal space, it sounds like gurgling.
Clucking: Similar to a hen's cluck, alpacas cluck when a mother is concerned for her cria. Male alpacas cluck to signal friendly behavior.
Screaming: Their screams are extremely deafening and loud. They will scream when they are not handled correctly or when they are being attacked by a potential enemy.
Screeching: A bird-like cry, presumably intended to terrify the opponent. This sound is typically used by male alpacas when they are in a fight over dominance. When a female screeches, it is more of a growl when she is angry.

Reproduction
Females are induced ovulators; meaning the act of mating and the presence of semen causes them to ovulate. Females usually conceive after just one breeding, but occasionally do have trouble conceiving. Artificial insemination is technically difficult, expensive and not common, but it can be accomplished. Embryo transfer is more widespread.

A male is usually ready to mate for the first time between two and three years of age. It is not advisable to allow a young female to be bred until she is mature and has reached two-thirds of her mature weight. Over-breeding a young female before conception is possibly a common cause of uterine infections. As the age of maturation varies greatly between individuals, it is usually recommended that novice breeders wait until females are 18 months of age or older before initiating breeding.

Alpacas can breed at any time throughout the year but it is more difficult to breed in the winter. Most breed during autumn or late spring. The most popular way to have alpacas mate is pen mating. Pen mating is when they move both the female and the desired male into a pen. Another way is paddock mating where one male alpaca is let loose in the paddock with several female alpacas.

The gestation period is, on average, 11.5 months, and usually results in a single offspring, or cria. Twins are rare, occurring about once per 1000 deliveries. Cria are generally between 15 and 19 pounds, and are standing 30 to 90 minutes after birth. After a female gives birth, she is generally receptive to breeding again after about two weeks. Crias may be weaned through human intervention at about six months old and 60 pounds, but many breeders prefer to allow the female to decide when to wean her offspring; they can be weaned earlier or later depending on their size and emotional maturity.

The average lifespan of an alpaca is between 15 and 20 years, and the longest-lived alpaca on record is 27 years.


Pests and diseases
Cattle tuberculosis can also infect alpacas: Mycobacterium bovis also causes TB in this species worldwide. Krajewska‐Wędzina et al., 2020 detect M. bovis in individuals traded from the United Kingdom to Poland. To accomplish this they develop a seroassay which correctly identifies positive subjects which are false negative for a common skin test. Krajewska‐Wędzina et al. also find that alpacas are unusual in mounting a competent early-infection immune response. Bernitz et al., 2021 believe this to generalise to all camelids.

Habitat and lifestyle
Alpacas can be found throughout most of South America. They typically live in temperate conditions in the mountains with high altitudes.

They are easy to care for since they are not limited to a specific type of environment. Animals such as flamingos, condors, spectacled bears, mountain lions, coyotes, llamas, and sheep live near alpacas when they are in their natural habitat.

Population
Alpacas are native to Peru, but can be found throughout the globe in captivity. Peru currently has the largest alpaca population, with over half the world's animals. The population declined drastically after the Spanish Conquistadors invaded the Andes mountains in 1532, after which 98% of the animals were destroyed. The Spanish also brought with them diseases that were fatal to alpacas.

European conquest forced the animals to move higher into the mountains, which remained there permanently. Although alpacas had almost been wiped out completely, they were rediscovered sometime during the 19th century by Europeans. After finding uses for them, the animals became important to societies during the industrial revolution.

In popular culture
Nuzzle and Scratch was a British children's television programme featuring two fictional alpacas that was first broadcast between 2008 and 2011.

Interest in alpacas grew as a result of Depp v. Heard, the 2022 trial in which Johnny Depp sued Amber Heard for defamation in Virginia after Heard wrote an op-ed saying she was a public victim of domestic violence. Depp testified, under oath, that he would not make another Pirates of the Caribbean film for "300 million dollars and a million alpacas".

Diet

Alpacas chew their food which ends up being mixed with their cud and saliva and then they swallow it. Alpacas usually eat 1.5% of their body weight daily for normal growth. They mainly need pasture grass, hay, or silage but some may also need supplemental energy and protein foods and they will also normally try to chew on almost anything (e.g. empty bottle). Most alpaca ranchers rotate their feeding grounds so the grass can regrow and fecal parasites may die before reusing the area. Pasture grass is a great source of protein. When seasons change, the grass loses or gains more protein. For example, in the spring, the pasture grass has about 20% protein while in the summer, it only has 6%. They need more energy supplements in the winter to produce body heat and warmth. They get their fiber from hay or from long stems which provides them with vitamin E. Green grass contains vitamin A and E.

Alpacas can eat natural unfertilized grass; however, ranchers can also supplement grass with low-protein grass hay. To provide selenium and other necessary vitamins, ranchers will feed their domestic alpacas a daily dose of grain to provide additional nutrients that are not fully obtained from their primary diet. Alpacas may obtain the necessary vitamins in their native grazing ranges.

Digestion
Alpacas, like other camelids, have a three-chambered stomach; combined with chewing cud, this three-chambered system allows maximum extraction of nutrients from low-quality forages. Alpacas are not ruminants, pseudo-ruminants, or modified ruminants, as there are many differences between the anatomy and physiology of a camelid and a ruminant stomach.

Alpacas will chew their food in a figure eight motion, swallow the food, and then pass it into one of the stomach's chambers. The first and second chambers (called C1 and C2) are anaerobic fermentation chambers where the fermentation process begins. The alpaca will further absorb nutrients and water in the first part of the third chamber. The end of the third chamber (called C3) is where the stomach secretes acids to digest food and is the likely place where an alpaca will have ulcers if stressed.

Poisonous plants
Many plants are poisonous to the alpaca, including the bracken fern, Madagascar ragwort, oleander, and some azaleas. In common with similar livestock, others include acorns, African rue, agave, amaryllis, autumn crocus, bear grass, broom snakeweed, buckwheat, ragweed, buttercups, calla lily, orange tree foliage, carnations, castor beans, and many others.

Fiber
Main article: Alpaca fiber
Alpacas are typically sheared once per year in the spring. Each shearing produces approximately 2.3 to 4.5 kilograms (5 to 10 pounds) of fiber per alpaca. An adult alpaca might produce 1.4 to 2.6 kilograms (50 to 90 ounces) of first-quality fiber as well as 1.4 to 2.8 kilograms (50 to 100 ounces) of second- and third-quality fiber. The quality of alpaca fiber is determined by how crimpy it is. Typically, the greater the number of small folds in the fiber, the greater the quality.

Prices
Alpacas were the subject of a speculative bubble between their introduction to North America in 1984 and the early 21st century. The price for American alpacas ranged from US$50 for a castrated male (gelding) to US$675,000 for the highest in the world, depending on breeding history, sex, and color. In 2006, researchers warned that the higher prices sought for alpaca breeding stock were largely speculative and not supported by market fundamentals, given the low inherent returns per head from the main end product, alpaca fiber, and prices into the $100s per head rather than $10,000s would be required for a commercially viable fiber production herd.

Marketed as "the investment you can hug" in television commercials by the Alpaca Owners and Breeders Association, the market for alpacas was almost entirely dependent on breeding and selling animals to new buyers, a classic sign of speculative bubbles in livestock. The bubble burst in 2007, with the price of alpaca breeding stock dropping by thousands of dollars each year thereafter. Many farmers found themselves unable to sell animals for any price, or even give them away.

It is possible to raise up to 25 alpacas per hectare (10/acre), as they have a designated area for waste products and keep their eating area away from their waste area. However, this ratio differs from country to country and is highly dependent on the quality of pasture available (in many desert locations it is generally only possible to run one to three animals per acre due to lack of suitable vegetation). Fiber quality is the primary variant in the price achieved for alpaca wool; in Australia, it is common to classify the fiber by the thickness of the individual hairs and by the amount of vegetable matter contained in the supplied shearings.

Livestock

Alpacas need to eat 1–2% of their body weight per day, so about two 27 kg (60 lb) bales of grass hay per month per animal. When formulating a proper diet for alpacas, water and hay analysis should be performed to determine the proper vitamin and mineral supplementation program. Two options are to provide free choice salt/mineral powder or feed a specially formulated ration. Indigenous to the highest regions of the Andes, this harsh environment has created an extremely hardy animal, so only minimal housing and predator fencing are needed. The alpacas' three-chambered stomachs allow for extremely efficient digestion. There are no viable seeds in the manure, because alpacas prefer to only eat tender plant leaves, and will not consume thick plant stems; therefore, alpaca manure does not need composting to enrich pastures or ornamental landscaping. Nail and teeth trimming are needed every six to twelve months, along with annual shearing.

Similar to ruminants, such as cattle and sheep, alpacas have only lower teeth at the front of their mouths; therefore, they do not pull the grass up by the roots. Rotating pastures is still important, though, as alpacas have a tendency to regraze an area repeatedly. Alpacas are fiber-producing animals; they do not need to be slaughtered to reap their product, and their fiber is a renewable resource that grows yearly.

Cultural presence

Alpacas are closely tied to cultural practices for Andeans people. Prior to colonization, the image of the alpaca was used in rituals and in their religious practices. Since the people in the region depended heavily on these animals for their sustenance, the alpaca was seen as a gift from Pachamama. Alpacas were used for their meat, fibers for clothing, and art, and their images in the form of conopas.

Conopas take their appearance from the Suri alpacas, with long locks flanking their sides and bangs covering the eyes, and a depression on the back. This depression is used in ritual practices, usually filled with coca leaves and fat from alpacas and lamas, to bring fertility and luck. While their use was prevalent before colonization, the attempts to convert the Andean people to Catholicism led to the acquisition of more than 3,400 conopas in Lima alone.

The origin of alpacas is depicted in legend; the legend states they came to be in the world after a goddess fell in love with a man. The goddess' father only allowed her to be with her lover if he cared for her herd of alpacas. On top of caring for the herd, he was to always carry a small animal for his entire life. As the goddess came into our world, the alpacas followed her. Everything was fine until the man set the small animal down, and the goddess fled back to her home. On her way back home, the man attempted to stop her and her herd from fleeing. While he was not able to stop her from returning, he was able to stop a few alpacas from returning. These alpacas who did not make it back are said to be seen today in the swampy lands in the Andes waiting for the end of the world, so they may return to their goddess.

Great Apes - Hominids (Hominidae) by millicand@rocketmail.com

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Great Apes - Hominids (Hominidae)

The Hominidae, whose members are known as the great apes or hominids, are a taxonomic family of primates that includes eight extant species in four genera: Pongo (the Bornean, Sumatran and Tapanuli orangutan); Gorilla (the eastern and western gorilla); Pan (the chimpanzee and the bonobo); and Homo, of which only modern humans (Homo sapiens) remain.

Numerous revisions in classifying the great apes have caused the use of the term hominid to change over time. The original meaning of "hominid" referred only to humans (Homo) and their closest extinct relatives. However, by the 1990s humans, apes, and their ancestors were considered to be "hominids".

The earlier restrictive meaning has now been largely assumed by the term hominin, which comprises all members of the human clade after the split from the chimpanzees (Pan). The current meaning of "hominid" includes all the great apes including humans. Usage still varies, however, and some scientists and laypersons still use "hominid" in the original restrictive sense; the scholarly literature generally shows the traditional usage until the turn of the 21st century.

Within the taxon Hominidae, a number of extant and extinct genera are grouped with the humans, chimpanzees, and gorillas in the subfamily Homininae; others with orangutans in the subfamily Ponginae (see classification graphic below). The most recent common ancestor of all Hominidae lived roughly 14 million years ago, when the ancestors of the orangutans speciated from the ancestral line of the other three genera. Those ancestors of the family Hominidae had already speciated from the family Hylobatidae (the gibbons), perhaps 15 to 20 million years ago.

Due to the close genetic relationship between humans and the other great apes, certain animal rights organizations, such as the Great Ape Project, argue that nonhuman great apes are persons and should be given basic human rights. Twenty-nine countries have instituted research bans to protect great apes from any kind of scientific testing.

Evolution
See also: Human evolution

Sumatran orangutan (Pongo abelii)
In the early Miocene, about 22 million years ago, there were many species of arboreally adapted primitive catarrhines from East Africa; the variety suggests a long history of prior diversification. Fossils from 20 million years ago include fragments attributed to Victoriapithecus, the earliest Old World monkey. Among the genera thought to be in the ape lineage leading up to 13 million years ago are Proconsul, Rangwapithecus, Dendropithecus, Limnopithecus, Nacholapithecus, Equatorius, Nyanzapithecus, Afropithecus, Heliopithecus, and Kenyapithecus, all from East Africa.

At sites far distant from East Africa, the presence of other generalized non-cercopithecids, that is, non-monkey primates, of middle Miocene age—Otavipithecus from cave deposits in Namibia, and Pierolapithecus and Dryopithecus from France, Spain and Austria—is further evidence of a wide diversity of ancestral ape forms across Africa and the Mediterranean basin during the relatively warm and equable climatic regimes of the early and middle Miocene. The most recent of these far-flung Miocene apes (hominoids) is Oreopithecus, from the fossil-rich coal beds in northern Italy and dated to 9 million years ago.

Molecular evidence indicates that the lineage of gibbons (family Hylobatidae), the "lesser apes", diverged from that of the great apes some 18–12 million years ago, and that of orangutans (subfamily Ponginae) diverged from the other great apes at about 12 million years. There are no fossils that clearly document the ancestry of gibbons, which may have originated in a still-unknown South East Asian hominoid population; but fossil proto-orangutans, dated to around 10 million years ago, may be represented by Sivapithecus from India and Griphopithecus from Turkey. Species close to the last common ancestor of gorillas, chimpanzees and humans may be represented by Nakalipithecus fossils found in Kenya and Ouranopithecus fossils found in Greece. Molecular evidence suggests that between 8 and 4 million years ago, first the gorillas (genus Gorilla), and then the chimpanzees (genus Pan) split off from the line leading to humans. Human DNA is approximately 98.4% identical to that of chimpanzees when comparing single nucleotide polymorphisms (see human evolutionary genetics). The fossil record, however, of gorillas and chimpanzees is limited; both poor preservation—rain forest soils tend to be acidic and dissolve bone—and sampling bias probably contribute most to this problem.

Other hominins probably adapted to the drier environments outside the African equatorial belt; and there they encountered antelope, hyenas, elephants and other forms becoming adapted to surviving in the East African savannas, particularly the regions of the Sahel and the Serengeti. The wet equatorial belt contracted after about 8 million years ago, and there is very little fossil evidence for the divergence of the hominin lineage from that of gorillas and chimpanzees—which split was thought to have occurred around that time. The earliest fossils argued by some to belong to the human lineage are Sahelanthropus tchadensis (7 Ma) and Orrorin tugenensis (6 Ma), followed by Ardipithecus (5.5–4.4 Ma), with species Ar. kadabba and Ar. ramidus.

Taxonomy
Further information: Human taxonomy
Terminology

Humans are one of the four extant hominid genera.
The classification of the great apes has been revised several times in the last few decades; these revisions have led to a varied use of the word "hominid" over time. The original meaning of the term referred to only humans and their closest relatives—what is now the modern meaning of the term "hominin". The meaning of the taxon Hominidae changed gradually, leading to a modern usage of "hominid" that includes all the great apes including humans.

A number of very similar words apply to related classifications:

A hominoid, sometimes called an ape, is a member of the superfamily Hominoidea: extant members are the gibbons (lesser apes, family Hylobatidae) and the hominids.
A hominid is a member of the family Hominidae, the great apes: orangutans, gorillas, chimpanzees and humans.
A hominine is a member of the subfamily Homininae: gorillas, chimpanzees, and humans (excludes orangutans).
A hominin is a member of the tribe Hominini: chimpanzees and humans.
A homininan, following a suggestion by Wood and Richmond (2000), would be a member of the subtribe Hominina of the tribe Hominini: that is, modern humans and their closest relatives, including Australopithecina, but excluding chimpanzees.
A human is a member of the genus Homo, of which Homo sapiens is the only extant species, and within that Homo sapiens sapiens is the only surviving subspecies.

Extant and fossil relatives of humans

Hominidae was originally the name given to the family of humans and their (extinct) close relatives, with the other great apes (that is, the orangutans, gorillas and chimpanzees) all being placed in a separate family, the Pongidae. However, that definition eventually made Pongidae paraphyletic because at least one great ape species (the chimpanzees) proved to be more closely related to humans than to other great apes. Most taxonomists today encourage monophyletic groups—this would require, in this case, the use of Pongidae to be restricted to just one closely related grouping. Thus, many biologists now assign Pongo (as the subfamily Ponginae) to the family Hominidae. The taxonomy shown here follows the monophyletic groupings according to the modern understanding of human and great ape relationships.

Humans and close relatives including the tribes Hominini and Gorillini form the subfamily Homininae (see classification graphic below). (A few researchers go so far as to refer the chimpanzees and the gorillas to the genus Homo along with humans.) But, those fossil relatives more closely related to humans than the chimpanzees represent the especially close members of the human family, and without necessarily assigning subfamily or tribal categories.

Many extinct hominids have been studied to help understand the relationship between modern humans and the other extant hominids. Some of the extinct members of this family include Gigantopithecus, Orrorin, Ardipithecus, Kenyanthropus, and the australopithecines Australopithecus and Paranthropus.

The exact criteria for membership in the tribe Hominini under the current understanding of human origins are not clear, but the taxon generally includes those species that share more than 97% of their DNA with the modern human genome, and exhibit a capacity for language or for simple cultures beyond their 'local family' or band. The theory of mind concept—including such faculties as empathy, attribution of mental state, and even empathetic deception—is a controversial criterion; it distinguishes the adult human alone among the hominids. Humans acquire this capacity after about four years of age, whereas it has not been proven (nor has it been disproven) that gorillas or chimpanzees ever develop a theory of mind. This is also the case for some New World monkeys outside the family of great apes, as, for example, the capuchin monkeys.

However, even without the ability to test whether early members of the Hominini (such as Homo erectus, Homo neanderthalensis, or even the australopithecines) had a theory of mind, it is difficult to ignore similarities seen in their living cousins. Orangutans have shown the development of culture comparable to that of chimpanzees, and some say the orangutan may also satisfy those criteria for the theory of mind concept. These scientific debates take on political significance for advocates of great ape personhood.

See also: List of hominoids
There are eight living species of great ape which are classified in four genera. The following classification is commonly accepted:

Family Hominidae: humans and other great apes; extinct genera and species excluded
Subfamily Ponginae
Tribe Pongini
Genus Pongo
Bornean orangutan, Pongo pygmaeus
Pongo pygmaeus pygmaeus
Pongo pygmaeus morio
Pongo pygmaeus wurmbii
Sumatran orangutan, Pongo abelii
Tapanuli orangutan, Pongo tapanuliensis
Subfamily Homininae
Tribe Gorillini
Genus Gorilla
Western gorilla, Gorilla gorilla
Western lowland gorilla, Gorilla gorilla gorilla
Cross River gorilla, Gorilla gorilla diehli
Eastern gorilla, Gorilla beringei
Mountain gorilla, Gorilla beringei beringei
Eastern lowland gorilla, Gorilla beringei graueri
Tribe Hominini
Subtribe Panina
Genus Pan
Chimpanzee, Pan troglodytes
Central chimpanzee, Pan troglodytes troglodytes
Western chimpanzee, Pan troglodytes verus
Nigeria-Cameroon chimpanzee, Pan troglodytes ellioti
Eastern chimpanzee, Pan troglodytes schweinfurthii
Bonobo, Pan paniscus
Subtribe Hominina
Genus Homo
Human, Homo sapiens
Anatomically modern human, Homo sapiens sapiens
Fossil

In addition to the extant species and subspecies, archaeologists, paleontologists, and anthropologists have discovered and classified numerous extinct great ape species as below, based on the taxonomy shown.

Tribe Lufengpithecini †
Lufengpithecus
Lufengpithecus lufengensis
Lufengpithecus keiyuanensis
Lufengpithecus hudienensis
Meganthropus
Meganthropus palaeojavanicus
Tribe Sivapithecini†
Ankarapithecus
Ankarapithecus meteai
Sivapithecus
Sivapithecus brevirostris
Sivapithecus punjabicus
Sivapithecus parvada
Sivapithecus sivalensis
Sivapithecus indicus
Gigantopithecus
Gigantopithecus bilaspurensis
Gigantopithecus blacki
Gigantopithecus giganteus
Tribe Pongini
Khoratpithecus†
Khoratpithecus ayeyarwadyensis
Khoratpithecus piriyai
Khoratpithecus chiangmuanensis
Pongo (orangutans)
Pongo hooijeri†
Subfamily Homininae
Tribe Dryopithecini †
Kenyapithecus
Kenyapithecus wickeri
Danuvius
Danuvius guggenmosi
Pierolapithecus
Pierolapithecus catalaunicus
Udabnopithecus
Udabnopithecus garedziensis
Ouranopithecus
Ouranopithecus macedoniensis
Otavipithecus
Otavipithecus namibiensis
Morotopithecus (placement disputed)
Morotopithecus bishopi
Oreopithecus (placement disputed)
Oreopithecus bambolii
Nakalipithecus
Nakalipithecus nakayamai
Anoiapithecus
Anoiapithecus brevirostris
Hispanopithecus
Hispanopithecus laietanus
Hispanopithecus crusafonti
Dryopithecus
Dryopithecus wuduensis
Dryopithecus fontani
Dryopithecus brancoi
Dryopithecus laietanus
Dryopithecus crusafonti
Rudapithecus
Rudapithecus hungaricus
Samburupithecus
Samburupithecus kiptalami
Tribe Gorillini
Chororapithecus † (placement debated)
Chororapithecus abyssinicus
Tribe Hominini
Subtribe Panina
Subtribe Hominina
Graecopithecus †
Graecopithecus freybergi
Sahelanthropus†
Sahelanthropus tchadensis
Orrorin†
Orrorin tugenensis
Ardipithecus†
Ardipithecus ramidus
Ardipithecus kadabba
Kenyanthropus†
Kenyanthropus platyops
Praeanthropus†
Praeanthropus bahrelghazali
Praeanthropus anamensis
Praeanthropus afarensis
Australopithecus†
Australopithecus africanus
Australopithecus garhi
Australopithecus sediba
Australopithecus deyiremeda
Paranthropus†
Paranthropus aethiopicus
Paranthropus robustus
Paranthropus boisei
Homo – close relatives of modern humans
Homo gautengensis† (also classified as H. habilis)
Homo rudolfensis† (membership in Homo uncertain)
Homo habilis† (membership in Homo uncertain)
Homo naledi†
Dmanisi Man, Homo georgicus† (thought by some to be an early subspecies of Homo erectus)
Homo ergaster† (considered by some to be an early subspecies of Homo erectus)
Homo erectus†
Homo erectus bilzingslebenensis †
Java Man, Homo erectus erectus †
Lantian Man, Homo erectus lantianensis †
Nanjing Man, Homo erectus nankinensis †
Peking Man, Homo erectus pekinensis †
Solo Man, Homo erectus soloensis †
Tautavel Man, Homo erectus tautavelensis †
Yuanmou Man, Homo erectus yuanmouensis †
Flores Man or Hobbit, Homo floresiensis†
Homo luzonensis †
Homo antecessor† (thought by some to be a late H. erectus or early H. heidelbergensis)
Homo heidelbergensis† (also classified as H. sapiens heidelbergensis)
Homo cepranensis† (also classified as H. heidelbergensis)
Homo helmei† (also classified as late H. heidelbergensis or early H. sapiens)
Homo tsaichangensis† (thought by some to be a subspecies of H. erectus or a Denisovan)
Denisovans (scientific name not yet assigned)†
Neanderthal, Homo neanderthalensis† (sometimes called Homo sapiens neanderthalensis)
Homo rhodesiensis† (thought by some to be an African subspecies of H. heidelbergensis or an early H. sapiens)
Modern human, Homo sapiens (sometimes called Homo sapiens sapiens)
Homo sapiens idaltu†
Archaic Homo sapiens†
Description

The great apes are tailless primates, with the smallest living species being the bonobo at 30 to 40 kilograms (66 to 88 lb) in weight, and the largest being the eastern gorillas, with males weighing 140 to 180 kilograms (310 to 400 lb). In all great apes, the males are, on average, larger and stronger than the females, although the degree of sexual dimorphism varies greatly among species. Hominid teeth are similar to those of the Old World monkeys and gibbons, although they are especially large in gorillas. The dental formula is
2.1.2.3
2.1.2.3
. Human teeth and jaws are markedly smaller for their size than those of other apes, which may be an adaptation to not only having supplanted with extensive tool use the role of jaws in hunting and fighting, but also eating cooked food since the end of the Pleistocene.

Behavior
Although most living species are predominantly quadrupedal, they are all able to use their hands for gathering food or nesting materials, and, in some cases, for tool use. They build complex sleeping platforms, also called nests, in trees to sleep in at night, but chimpanzees and gorillas also build terrestrial nests, and gorillas can also sleep on the bare ground.

All species are omnivorous, although chimpanzees and orangutans primarily eat fruit. When gorillas run short of fruit at certain times of the year or in certain regions, they resort to eating shoots and leaves, often of bamboo, a type of grass. Gorillas have extreme adaptations for chewing and digesting such low-quality forage, but they still prefer fruit when it is available, often going miles out of their way to find especially preferred fruits. Humans, since the Neolithic revolution, have consumed mostly cereals and other starchy foods, including increasingly highly processed foods, as well as many other domesticated plants (including fruits) and meat.

Gestation in great apes lasts 8–9 months, and results in the birth of a single offspring, or, rarely, twins. The young are born helpless, and require care for long periods of time. Compared with most other mammals, great apes have a remarkably long adolescence, not being weaned for several years, and not becoming fully mature for eight to thirteen years in most species (longer in orangutans and humans). As a result, females typically give birth only once every few years. There is no distinct breeding season.

Gorillas and chimpanzees live in family groups of around five to ten individuals, although much larger groups are sometimes noted. Chimpanzees live in larger groups that break up into smaller groups when fruit becomes less available. When small groups of female chimpanzees go off in separate directions to forage for fruit, the dominant males can no longer control them and the females often mate with other subordinate males. In contrast, groups of gorillas stay together regardless of the availability of fruit. When fruit is hard to find, they resort to eating leaves and shoots.

This fact is related to gorillas' greater sexual dimorphism relative to that of chimpanzees; that is, the difference in size between male and female gorillas is much greater than that between male and female chimpanzees. This enables gorilla males to physically dominate female gorillas more easily. In both chimpanzees and gorillas, the groups include at least one dominant male, and young males leave the group at maturity.

Legal status
Main articles: Great ape personhood, Great Ape Project, and Countries banning non-human ape experimentation
Due to the close genetic relationship between humans and the other great apes, certain animal rights organizations, such as the Great Ape Project, argue that nonhuman great apes are persons and, per the Declaration on Great Apes, should be given basic human rights. In 1999, New Zealand was the first country to ban any great ape experimentation, and now 29 countries have currently instituted a research ban to protect great apes from any kind of scientific testing.

On 25 June 2008, the Spanish parliament supported a new law that would make "keeping apes for circuses, television commercials or filming" illegal. On 8 September 2010, the European Union banned the testing of great apes.

Capuchin Monkey (Cebinae) by millicand@rocketmail.com

© millicand@rocketmail.com, all rights reserved.

Capuchin Monkey (Cebinae)

The capuchin monkeys are New World monkeys of the subfamily Cebinae. They are readily identified as the "organ grinder" monkey, and have been used in many movies and television shows. The range of capuchin monkeys includes some tropical forests in Central America and South America as far south as northern Argentina. In Central America, where they are called white-faced monkeys ("carablanca"), they usually occupy the wet lowland forests on the Caribbean coast of Costa Rica and Panama and deciduous dry forest on the Pacific coast.

Etymology
The word "capuchin" derives from the Order of Friars Minor Capuchin, who wear brown robes with large hoods. When Portuguese explorers reached the Americas in the 15th century, they found small monkeys whose coloring resembled these friars, especially when in their robes with hoods down, and named them capuchins. When the scientists described a specimen (thought to be a golden-bellied capuchin) they noted that: "his muzzle of a tanned color, ... with the lighter color around his eyes that melts into the white at the front, his cheeks ..., give him the looks that involuntarily reminds us of the appearance that historically in our country represents ignorance, laziness, and sensuality." The scientific name of the genus, Cebus comes from the Greek word kêbos, meaning a long-tailed monkey.

Classification
The species-level taxonomy of this subfamily remains highly controversial, and alternative treatments than the one listed below have been suggested.

In 2011, Jessica Lynch Alfaro et al. proposed that the robust capuchins (formerly the C. apella group) be placed in a separate genus, Sapajus, from the gracile capuchins (formerly the C. capucinus group) which retain the genus Cebus. Other primatologists, such as Paul Garber, have begun using this classification.

According to genetic studies led by Lynch Alfaro in 2011, the gracile and robust capuchins diverged approximately 6.2 million years ago. Lynch Alfaro suspects that the divergence was triggered by the creation of the Amazon River, which separated the monkeys in the Amazon north of the Amazon River, who then evolved into the gracile capuchins. Those in the Atlantic Forest south of the river evolved into the robust capuchins. Gracile capuchins have longer limbs relative to their body size than robust capuchins, and have rounder skulls, whereas robust capuchins have jaws better adapted for opening hard nuts. Robust capuchins have crests and the males have beards.

Genus Cebus
Colombian white-faced capuchin or Colombian white-headed capuchin, Cebus capucinus
Panamanian white-faced capuchin or Panamanian white-headed capuchin, Cebus imitator
Marañón white-fronted capuchin, Cebus yuracus
Shock-headed capuchin, Cebus cuscinus
Spix's white-fronted capuchin, Cebus unicolor
Humboldt's white-fronted capuchin, Cebus albifrons
Guianan weeper capuchin, Cebus olivaceus
Chestnut weeper capuchin, Cebus castaneus
Ka'apor capuchin, Cebus kaapori
Venezuelan brown capuchin, Cebus brunneus
Sierra de Perijá white-fronted capuchin, Cebus leucocephalus
Río Cesar white-fronted capuchin, Cebus cesare
Varied white-fronted capuchin, Cebus versicolor
Santa Marta white-fronted capuchin, Cebus malitiosus
Ecuadorian white-fronted capuchin, Cebus aequatorialis

Genus Sapajus
Black-capped, brown or tufted capuchin, Sapajus apella
Guiana brown capuchin, Sapajus apella apella
Sapajus apella fatuellus
Large-headed capuchin, Sapajus apella macrocephalus
Margarita Island capuchin, Sapajus apella margaritae
Sapajus apella peruanus
Sapajus apella tocantinus
Blond capuchin, Sapajus flavius*
Black-striped capuchin, Sapajus libidinosus
Sapajus libidinosus juruanus
Sapajus libidinosus libidinosus
Sapajus libidinosus pallidus
Sapajus libidinosus paraguayanus
Azaras's capuchin, Sapajus cay
Black capuchin, Sapajus nigritus
Sapajus nigritus cucullatus
Sapajus nigritus nigritus
Crested capuchin or robust tufted capuchin, Sapajus robustus
Golden-bellied capuchin, Sapajus xanthosternos
* Rediscovered species.

The oldest known crown platyrrhine and member of Cebidae, Panamacebus transitus, is estimated to have lived 21 million years ago. It is the earliest known fossil evidence of a mammal travelling between South and North America.

Physical characteristics
Capuchins are black, brown, buff or whitish, but their exact color and pattern depends on the species involved. Capuchin monkeys are usually dark brown with a cream/off-white coloring around their necks. They reach a length of 30 to 56 cm (12 to 22 in), with tails that are just as long as the body. On average, they weigh from 1.4 to 4 kg (3 to 9 pounds) and live up to 25 years old in their natural habitats,[citation needed] and up to 35 in captivity.

Habitat and distribution
Capuchins prefer environments that give them access to shelter and easy food, such as low-lying forests, mountain forests, and rain forests. They are particularly abundant in Argentina, Brazil, Costa Rica, Honduras, Paraguay, and Peru. They use these areas for shelter at night and food access during the day. The canopy of the trees allows for protection from threats above, and the capuchin monkeys' innate ability to climb trees with ease allows them to escape and hide from predators on the jungle floor. This environment is mutually beneficial for the capuchins and for the ecosystem in which they inhabit. This is because they spread their seed leftovers and fecal matter across the forest floor which helps new plants to grow, therefore adding to the already abundant foliage that shelters the capuchin.

Behavior
Like most New World monkeys, capuchins are diurnal and arboreal. Capuchins are polygamous, and the females mate throughout the year, but only go through a gestation period once every 2 years between December and April. Females bear young every two years following a 160- to 180-day gestation. The young cling to their mother's chest until they are larger, then they move to her back. Adult male capuchin rarely take part in caring for the young. Juveniles become fully mature within four years for females and eight years for males. In captivity, individuals have reached an age of 50 years, although natural life expectancy is only 15 to 25 years. Capuchins live in groups of 6–40 members, consisting of related females, their offspring, and several males.

Diet
The capuchin monkey feeds on a vast range of food types, and is more varied than other monkeys in the family Cebidae. They are omnivores, and consume a variety of plant parts such as leaves, flower and fruit, seeds, pith, woody tissue, sugarcane, bulb, and exudates, as well as arthropods, molluscs, a variety of vertebrates, and even primates. Recent findings of old stone tools in Capuchin habitats have suggested that recently the Capuchins have switched from small nuts, such as cashews, to larger and harder nuts. Capuchins have also been observed to be particularly good at catching frogs. They are characterized as innovative and extreme foragers because of their ability to acquire sustenance from a wide collection of unlikely food, which may assure their survival in habitats with extreme food limitation. Capuchins living near water will also eat crabs and shellfish by cracking their shells with stones.

Social structure
Capuchin monkeys often live in large groups of 10 to 35 individuals within the forest, although they can easily adapt to places colonized by humans. The Capuchins have discrete hierarchies that are distinguished by age and sex. Usually, a single male will dominate the group, and he will have primary rights to mate with the females of the group. However, the white-headed capuchin groups are led by both an alpha male and an alpha female. Each group will cover a large territory, since members must search for the best areas to feed. These primates are territorial animals, distinctly marking a central area of their territory with urine and defending it against intruders, though outer areas may overlap. The stabilization of group dynamics is served through mutual grooming, and communication occurs between the monkeys through various calls. Their vocal communications have various meanings such as creating contact with one another, warning about a predator, and forming new groups. The social experience of the capuchins directly influences the development of attention in society. They create new social behaviors within multiple groups that signify different types of interactions. These include; tests of friendship, displays against enemies, infant and sexual intimacy. This creates social rituals that are designed to test the strength of social bonds and a reliance on social learning.

Mating
Capuchin females often direct most of their proceptive and mating behavior towards the alpha male. However, when the female reaches the end of her proceptive period, she may sometimes mate with up to six different subordinate males in one day. Strictly targeting the alpha male does not happen every time, as some females have been observed to mate with three to four different males. When an alpha female and a lower-ranking female want to mate with an alpha male, the more dominant female will get rights to the male over the lower-ranking one.

Intelligence
The capuchin is considered to be the most intelligent New World monkey and is often used in laboratories. The tufted monkey is especially noted for its long-term tool usage, one of the few examples of primate tool use other than by apes and humans. Upon seeing macaws eating palm nuts, cracking them open with their beaks, this monkey will select a few of the ripest fruits, nip off the tip of the fruit and drink down the juice, then seemingly discard the rest of the fruit with the nut inside. When these discarded fruits have hardened and become slightly brittle, the capuchin will gather them up again and take them to a large flat boulder where they have previously gathered a few river stones from up to a mile away. They will then use these stones, some of them weighing as much as the monkeys, to crack open the fruit to get to the nut inside. Young capuchins will watch this process to learn from the older, more experienced adults but it takes them 8 years to master this. The learning behavior of capuchins has been demonstrated to be directly linked to a reward rather than curiosity.

In 2005, experiments were conducted on the ability of capuchins to use money. After several months of training, the monkeys began exhibiting behaviors considered to reflect an understanding of the concept of a medium of exchange that were previously believed to be restricted to humans (such as responding rationally to price shocks). They showed the same propensity to avoid perceived losses demonstrated by human subjects and investors.

During the mosquito season, they crush millipedes and rub the result on their backs. This acts as a natural insect repellent.

Self-awareness
Further information: Self-awareness
When presented with a reflection, capuchin monkeys react in a way that indicates an intermediate state between seeing the mirror as another individual and recognizing the image as self.

Most animals react to seeing their reflections as if encountering another individual they do not recognize. An experiment with capuchins shows that they react to a reflection as a strange phenomenon, but not as if seeing a strange capuchin.

In the experiment, capuchins were presented with three different scenarios:

Seeing an unfamiliar, same-sex monkey on the other side of a clear barrier
Seeing a familiar, same-sex monkey on the other side of a clear barrier
A mirror showing a reflection of the monkey
In scenario 1, females appeared anxious and avoided eye-contact, while males made threatening gestures. In scenario 2, there was little reaction by either males or females.

When presented with a reflection, females gazed into their own eyes and made friendly gestures, such as lip-smacking and swaying. Males made more eye contact than with strangers or familiar monkeys but reacted with signs of confusion or distress, such as squealing, curling up on the floor, or trying to escape from the test room.

Theory of mind
Main article: Theory of mind
The question of whether capuchin monkeys have a theory of mind—whether they can understand what another creature may know or think—has been neither proven nor disproven conclusively. If confronted with a knower-guesser scenario, where one trainer can be observed to know the location of food and another trainer merely guesses the location of food, capuchin monkeys can learn to rely on the knower. This has, however, been repudiated as conclusive evidence for a theory of mind as the monkeys may have learned to discriminate knower and guess by other means. Until recently it was believed that non-human great apes did not possess a theory of mind either, although recent research indicates this may not be correct. Human children commonly develop a theory of mind around the ages 3 and 4.

Threats
Capuchin monkeys are clever and easy to train. As a result, they are used to help people who are quadriplegics in many developed countries. They have also become popular pets and attractions for street entertainment, and are hunted for meat by local people. Since they have a high reproductive rate and can easily adapt to their living environment, loss of the forest does not negatively impact the capuchin monkey populations as much as other species, although habitat fragmentation is still a threat. Natural predators include jaguars, cougars, jaguarundis, coyotes, tayras, snakes, crocodiles and birds of prey. The main predator of the tufted capuchin is the harpy eagle, which has been seen bringing several capuchin back to its nest.

Relationship with humans
Easily recognized as the "organ grinder" or "greyhound jockey" monkeys, capuchins are sometimes kept as exotic pets. Sometimes they plunder fields and crops and are seen as troublesome by nearby human populations. In some regions, they have become rare due to the destruction of their habitat.

They are also used as service animals, sometimes being called "nature's butlers". One organization has been training capuchin monkeys to assist quadriplegics as monkey helpers in a manner similar to mobility assistance dogs. After being socialized in a human home as infants, the monkeys undergo extensive training before being placed with a quadriplegic. Around the house, the monkeys help out by doing tasks including fetching objects, turning lights on and off, and opening drink bottles.

In 2010, the U.S. federal government revised its definition of service animal under the Americans with Disabilities Act (ADA). Non-human primates are no longer recognized as service animals under the ADA. The American Veterinary Medical Association does not support the use of nonhuman primates as assistance animals because of animal welfare concerns, the potential for serious injury to people, and risks that primates may transfer dangerous diseases to humans.

Capuchin monkeys are the most common featured monkeys in film and television, with notable examples including: Night at the Museum (and its sequels), Outbreak, Monkey Shines ,Pirates of the Caribbean: The Curse of the Black Pearl (and its sequels), Zookeeper, George of the Jungle, and The Hangover Part II. Ross Geller (David Schwimmer) on the NBC sitcom Friends had a capuchin monkey named Marcel. Crystal the Monkey is a famous monkey actress.

Jellyfish - Sea Jellies - Medusa (Subphylum Medusozoa) by millicand@rocketmail.com

© millicand@rocketmail.com, all rights reserved.

Jellyfish - Sea Jellies - Medusa (Subphylum Medusozoa)

Jellyfish, also known sea jellies, are the medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria.

Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles, although a few are anchored to the seabed by stalks rather than being mobile. The bell can pulsate to provide propulsion for highly efficient locomotion. The tentacles are armed with stinging cells and may be used to capture prey and defend against predators. Jellyfish have a complex life cycle. The medusa is normally the sexual phase, which produces planula larvae; these then disperse widely and enter a sedentary polyp phase, before reaching sexual maturity.

Jellyfish are found all over the world, from surface waters to the deep sea. Scyphozoans (the "true jellyfish") are exclusively marine, but some hydrozoans with a similar appearance live in freshwater. Large, often colorful, jellyfish are common in coastal zones worldwide. The medusae of most species are fast-growing, and mature within a few months then die soon after breeding, but the polyp stage, attached to the seabed, may be much more long-lived. Jellyfish have been in existence for at least 500 million years, and possibly 700 million years or more, making them the oldest multi-organ animal group.

Jellyfish are eaten by humans in certain cultures. They are considered a delicacy in some Asian countries, where species in the Rhizostomeae order are pressed and salted to remove excess water. Australian researchers have described them as a "perfect food": sustainable and protein-rich but relatively low in food energy.

They are also used in research, where the green fluorescent protein used by some species to cause bioluminescence has been adapted as a fluorescent marker for genes inserted into other cells or organisms.

The stinging cells used by jellyfish to subdue their prey can injure humans. Thousands of swimmers worldwide are stung every year, with effects ranging from mild discomfort to serious injury or even death. When conditions are favourable, jellyfish can form vast swarms, which can be responsible for damage to fishing gear by filling fishing nets, and sometimes clog the cooling systems of power and desalination plants which draw their water from the sea.


Names
The name jellyfish, in use since 1796, has traditionally been applied to medusae and all similar animals including the comb jellies (ctenophores, another phylum). The term jellies or sea jellies is more recent, having been introduced by public aquaria in an effort to avoid use of the word "fish" with its modern connotation of an animal with a backbone, though shellfish, cuttlefish and starfish are not vertebrates either. In scientific literature, "jelly" and "jellyfish" have been used interchangeably. Many sources refer to only scyphozoans as "true jellyfish".

A group of jellyfish is called a "smack" or a "smuck".

Definition
The term jellyfish broadly corresponds to medusae, that is, a life-cycle stage in the Medusozoa. The American evolutionary biologist Paulyn Cartwright gives the following general definition:

Typically, medusozoan cnidarians have a pelagic, predatory jellyfish stage in their life cycle; staurozoans are the exceptions [as they are stalked].

The Merriam-Webster dictionary defines jellyfish as follows:

A free-swimming marine coelenterate that is the sexually reproducing form of a hydrozoan or scyphozoan and has a nearly transparent saucer-shaped body and extensible marginal tentacles studded with stinging cells.

Given that jellyfish is a common name, its mapping to biological groups is inexact. Some authorities have called the comb jellies and certain salps jellyfish, though other authorities state that neither of these are jellyfish, which they consider should be limited to certain groups within the medusozoa.

The non-medusozoan clades called jellyfish by some but not all authorities (both agreeing and disagreeing citations are given in each case) are indicated with on the following cladogram of the animal kingdom:

Jellyfish are not a clade, as they include most of the Medusozoa, barring some of the Hydrozoa. The medusozoan groups included by authorities are indicated on the following phylogenetic tree by the presence of citations. Names of included jellyfish, in English where possible, are shown in boldface; the presence of a named and cited example indicates that at least that species within its group has been called a jellyfish.

Taxonomy
The subphylum Medusozoa includes all cnidarians with a medusa stage in their life cycle. The basic cycle is egg, planula larva, polyp, medusa, with the medusa being the sexual stage. The polyp stage is sometimes secondarily lost. The subphylum include the major taxa, Scyphozoa (large jellyfish), Cubozoa (box jellyfish) and Hydrozoa (small jellyfish), and excludes Anthozoa (corals and sea anemones). This suggests that the medusa form evolved after the polyps. Medusozoans have tetramerous symmetry, with parts in fours or multiples of four.

The four major classes of medusozoan Cnidaria are:
Scyphozoa are sometimes called true jellyfish, though they are no more truly jellyfish than the others listed here. They have tetra-radial symmetry. Most have tentacles around the outer margin of the bowl-shaped bell, and long, oral arms around the mouth in the center of the subumbrella.
Cubozoa (box jellyfish) have a (rounded) box-shaped bell, and their velarium assists them to swim more quickly. Box jellyfish may be related more closely to scyphozoan jellyfish than either are to the Hydrozoa.
Hydrozoa medusae also have tetra-radial symmetry, nearly always have a velum (diaphragm used in swimming) attached just inside the bell margin, do not have oral arms, but a much smaller central stalk-like structure, the manubrium, with terminal mouth opening, and are distinguished by the absence of cells in the mesoglea. Hydrozoa show great diversity of lifestyle; some species maintain the polyp form for their entire life and do not form medusae at all (such as Hydra, which is hence not considered a jellyfish), and a few are entirely medusal and have no polyp form.
Staurozoa (stalked jellyfish) are characterized by a medusa form that is generally sessile, oriented upside down and with a stalk emerging from the apex of the "calyx" (bell), which attaches to the substrate. At least some Staurozoa also have a polyp form that alternates with the medusoid portion of the life cycle. Until recently, Staurozoa were classified within the Scyphozoa.
There are over 200 species of Scyphozoa, about 50 species of Staurozoa, about 50 species of Cubozoa, and the Hydrozoa includes about 1000–1500 species that produce medusae, but many more species that do not.

Fossil history
Since jellyfish have no hard parts, fossils are rare. The oldest unambiguous fossil of a free-swimming medusa is Burgessomedusa from the mid Cambrian Burgess Shale of Canada, which is likely either a stem group of box jellyfish (Cubozoa) or Acraspeda (the clade including Staurozoa, Cubozoa, and Scyphozoa). Other claimed records from the Cambrian of China and Utah in the United States are uncertain, and possibly represent ctenophores instead.

Anatomy
The main feature of a true jellyfish is the umbrella-shaped bell. This is a hollow structure consisting of a mass of transparent jelly-like matter known as mesoglea, which forms the hydrostatic skeleton of the animal. 95% or more of the mesogloea consists of water, but it also contains collagen and other fibrous proteins, as well as wandering amoebocytes which can engulf debris and bacteria. The mesogloea is bordered by the epidermis on the outside and the gastrodermis on the inside. The edge of the bell is often divided into rounded lobes known as lappets, which allow the bell to flex. In the gaps or niches between the lappets are dangling rudimentary sense organs known as rhopalia, and the margin of the bell often bears tentacles.


Anatomy of a scyphozoan jellyfish
On the underside of the bell is the manubrium, a stalk-like structure hanging down from the centre, with the mouth, which also functions as the anus, at its tip. There are often four oral arms connected to the manubrium, streaming away into the water below. The mouth opens into the gastrovascular cavity, where digestion takes place and nutrients are absorbed. This is subdivided by four thick septa into a central stomach and four gastric pockets. The four pairs of gonads are attached to the septa, and close to them four septal funnels open to the exterior, perhaps supplying good oxygenation to the gonads. Near the free edges of the septa, gastric filaments extend into the gastric cavity; these are armed with nematocysts and enzyme-producing cells and play a role in subduing and digesting the prey. In some scyphozoans, the gastric cavity is joined to radial canals which branch extensively and may join a marginal ring canal. Cilia in these canals circulate the fluid in a regular direction.


Discharge mechanism of a nematocyst
The box jellyfish is largely similar in structure. It has a squarish, box-like bell. A short pedalium or stalk hangs from each of the four lower corners. One or more long, slender tentacles are attached to each pedalium. The rim of the bell is folded inwards to form a shelf known as a velarium which restricts the bell's aperture and creates a powerful jet when the bell pulsates, allowing box jellyfish to swim faster than true jellyfish. Hydrozoans are also similar, usually with just four tentacles at the edge of the bell, although many hydrozoans are colonial and may not have a free-living medusal stage. In some species, a non-detachable bud known as a gonophore is formed that contains a gonad but is missing many other medusal features such as tentacles and rhopalia. Stalked jellyfish are attached to a solid surface by a basal disk, and resemble a polyp, the oral end of which has partially developed into a medusa with tentacle-bearing lobes and a central manubrium with four-sided mouth.

Most jellyfish do not have specialized systems for osmoregulation, respiration and circulation, and do not have a central nervous system. Nematocysts, which deliver the sting, are located mostly on the tentacles; true jellyfish also have them around the mouth and stomach. Jellyfish do not need a respiratory system because sufficient oxygen diffuses through the epidermis. They have limited control over their movement, but can navigate with the pulsations of the bell-like body; some species are active swimmers most of the time, while others largely drift. The rhopalia contain rudimentary sense organs which are able to detect light, water-borne vibrations, odour and orientation. A loose network of nerves called a "nerve net" is located in the epidermis. Although traditionally thought not to have a central nervous system, nerve net concentration and ganglion-like structures could be considered to constitute one in most species. A jellyfish detects stimuli, and transmits impulses both throughout the nerve net and around a circular nerve ring, to other nerve cells. The rhopalial ganglia contain pacemaker neurones which control swimming rate and direction.

In many species of jellyfish, the rhopalia include ocelli, light-sensitive organs able to tell light from dark. These are generally pigment spot ocelli, which have some of their cells pigmented. The rhopalia are suspended on stalks with heavy crystals at one end, acting like gyroscopes to orient the eyes skyward. Certain jellyfish look upward at the mangrove canopy while making a daily migration from mangrove swamps into the open lagoon, where they feed, and back again.

Box jellyfish have more advanced vision than the other groups. Each individual has 24 eyes, two of which are capable of seeing colour, and four parallel information processing areas that act in competition, supposedly making them one of the few kinds of animal to have a 360-degree view of its environment.

Box jellyfish eye
The study of jellyfish eye evolution is an intermediary to a better understanding of how visual systems evolved on Earth. Jellyfish exhibit immense variation in visual systems ranging from photoreceptive cell patches seen in simple photoreceptive systems to more derived complex eyes seen in box jellyfish. Major topics of jellyfish visual system research (with an emphasis on box jellyfish) include: the evolution of jellyfish vision from simple to complex visual systems), the eye morphology and molecular structures of box jellyfish (including comparisons to vertebrate eyes), and various uses of vision including task-guided behaviors and niche specialization.

Evolution
Experimental evidence for photosensitivity and photoreception in cnidarians antecedes the mid 1900s, and a rich body of research has since covered evolution of visual systems in jellyfish. Jellyfish visual systems range from simple photoreceptive cells to complex image-forming eyes. More ancestral visual systems incorporate extraocular vision (vision without eyes) that encompass numerous receptors dedicated to single-function behaviors. More derived visual systems comprise perception that is capable of multiple task-guided behaviors.

Although they lack a true brain, cnidarian jellyfish have a "ring" nervous system that plays a significant role in motor and sensory activity. This net of nerves is responsible for muscle contraction and movement and culminates the emergence of photosensitive structures. Across Cnidaria, there is large variation in the systems that underlie photosensitivity. Photosensitive structures range from non-specialized groups of cells, to more "conventional" eyes similar to those of vertebrates. The general evolutionary steps to develop complex vision include (from more ancestral to more derived states): non-directional photoreception, directional photoreception, low-resolution vision, and high-resolution vision. Increased habitat and task complexity has favored the high-resolution visual systems common in derived cnidarians such as box jellyfish.

Basal visual systems observed in various cnidarians exhibit photosensitivity representative of a single task or behavior. Extraocular photoreception (a form of non-directional photoreception), is the most basic form of light sensitivity and guides a variety of behaviors among cnidarians. It can function to regulate circadian rhythm (as seen in eyeless hydrozoans) and other light-guided behaviors responsive to the intensity and spectrum of light. Extraocular photoreception can function additionally in positive phototaxis (in planula larvae of hydrozoans), as well as in avoiding harmful amounts of UV radiation via negative phototaxis. Directional photoreception (the ability to perceive direction of incoming light) allows for more complex phototactic responses to light, and likely evolved by means of membrane stacking. The resulting behavioral responses can range from guided spawning events timed by moonlight to shadow responses for potential predator avoidance. Light-guided behaviors are observed in numerous scyphozoans including the common moon jelly, Aurelia aurita, which migrates in response to changes in ambient light and solar position even though they lack proper eyes.

The low-resolution visual system of box jellyfish is more derived than directional photoreception, and thus box jellyfish vision represents the most basic form of true vision in which multiple directional photoreceptors combine to create the first imaging and spatial resolution. This is different from the high-resolution vision that is observed in camera or compound eyes of vertebrates and cephalopods that rely on focusing optics. Critically, the visual systems of box jellyfish are responsible for guiding multiple tasks or behaviors in contrast to less derived visual systems in other jellyfish that guide single behavioral functions. These behaviors include phototaxis based on sunlight (positive) or shadows (negative), obstacle avoidance, and control of swim-pulse rate.

Box jellyfish possess "proper eyes" (similar to vertebrates) that allow them to inhabit environments that lesser derived medusae cannot. In fact, they are considered the only class in the clade Medusozoa that have behaviors necessitating spatial resolution and genuine vision. However, the lens in their eyes are more functionally similar to cup-eyes exhibited in low-resolution organisms, and have very little to no focusing capability. The lack of the ability to focus is due to the focal length exceeding the distance to the retina, thus generating unfocused images and limiting spatial resolution. The visual system is still sufficient for box jellyfish to produce an image to help with tasks such as object avoidance.

Utility as a model organism
Box jellyfish eyes are a visual system that is sophisticated in numerous ways. These intricacies include the considerable variation within the morphology of box jellyfishes' eyes (including their task/behavior specification), and the molecular makeup of their eyes including: photoreceptors, opsins, lenses, and synapses. The comparison of these attributes to more derived visual systems can allow for a further understanding of how the evolution of more derived visual systems may have occurred, and puts into perspective how box jellyfish can play the role as an evolutionary/developmental model for all visual systems.

Characteristics
Box jellyfish visual systems are both diverse and complex, comprising multiple photosystems. There is likely considerable variation in visual properties between species of box jellyfish given the significant inter-species morphological and physiological variation. Eyes tend to differ in size and shape, along with number of receptors (including opsins), and physiology across species of box jellyfish.

Box jellyfish have a series of intricate lensed eyes that are similar to those of more derived multicellular organisms such as vertebrates. Their 24 eyes fit into four different morphological categories. These categories consist of two large, morphologically different medial eyes (a lower and upper lensed eye) containing spherical lenses, a lateral pair of pigment slit eyes, and a lateral pair of pigment pit eyes. The eyes are situated on rhopalia (small sensory structures) which serve sensory functions of the box jellyfish and arise from the cavities of the exumbrella (the surface of the body) on the side of the bells of the jellyfish. The two large eyes are located on the mid-line of the club and are considered complex because they contain lenses. The four remaining eyes lie laterally on either side of each rhopalia and are considered simple. The simple eyes are observed as small invaginated cups of epithelium that have developed pigmentation. The larger of the complex eyes contains a cellular cornea created by a mono ciliated epithelium, cellular lens, homogenous capsule to the lens, vitreous body with prismatic elements, and a retina of pigmented cells. The smaller of the complex eyes is said to be slightly less complex given that it lacks a capsule but otherwise contains the same structure as the larger eye.

Box jellyfish have multiple photosystems that comprise different sets of eyes. Evidence includes immunocytochemical and molecular data that show photopigment differences among the different morphological eye types, and physiological experiments done on box jellyfish to suggest behavioral differences among photosystems. Each individual eye type constitutes photosystems that work collectively to control visually guided behaviors.

Box jellyfish eyes primarily use c-PRCs (ciliary photoreceptor cells) similar to that of vertebrate eyes. These cells undergo phototransduction cascades (process of light absorption by photoreceptors) that are triggered by c-opsins. Available opsin sequences suggest that there are two types of opsins possessed by all cnidarians including an ancient phylogenetic opsin, and a sister ciliary opsin to the c-opsins group. Box jellyfish could have both ciliary and cnidops (cnidarian opsins), which is something not previously believed to appear in the same retina. Nevertheless, it is not entirely evident whether cnidarians possess multiple opsins that are capable of having distinctive spectral sensitivities.

Comparison with other organisms
Comparative research on genetic and molecular makeup of box jellyfishes' eyes versus more derived eyes seen in vertebrates and cephalopods focuses on: lenses and crystallin composition, synapses, and Pax genes and their implied evidence for shared primordial (ancestral) genes in eye evolution.

Box jellyfish eyes are said to be an evolutionary/developmental model of all eyes based on their evolutionary recruitment of crystallins and Pax genes. Research done on box jellyfish including Tripedalia cystophora has suggested that they possess a single Pax gene, PaxB. PaxB functions by binding to crystallin promoters and activating them. PaxB in situ hybridization resulted in PaxB expression in the lens, retina, and statocysts. These results and the rejection of the prior hypothesis that Pax6 was an ancestral Pax gene in eyes has led to the conclusion that PaxB was a primordial gene in eye evolution, and that the eyes of all organisms likely share a common ancestor.

The lens structure of box jellyfish appears very similar to those of other organisms, but the crystallins are distinct in both function and appearance. Weak reactions were seen within the sera and there were very weak sequence similarities within the crystallins among vertebrate and invertebrate lenses. This is likely due to differences in lower molecular weight proteins and the subsequent lack of immunological reactions with antisera that other organisms' lenses exhibit.

All four of the visual systems of box jellyfish species investigated with detail (Carybdea marsupialis, Chiropsalmus quadrumanus, Tamoya haplonema and Tripedalia cystophora) have invaginated synapses, but only in the upper and lower lensed eyes. Different densities were found between the upper and lower lenses, and between species. Four types of chemical synapses have been discovered within the rhopalia which could help in understanding neural organization including: clear unidirectional, dense-core unidirectional, clear bidirectional, and clear and dense-core bidirectional. The synapses of the lensed eyes could be useful as markers to learn more about the neural circuit in box jellyfish retinal areas.

Evolution as a response to natural stimuli
The primary adaptive responses to environmental variation observed in box jellyfish eyes include pupillary constriction speeds in response to light environments, as well as photoreceptor tuning and lens adaptations to better respond to shifts between light environments and darkness. Interestingly, some box jellyfish species' eyes appear to have evolved more focused vision in response to their habitat.

Pupillary contraction appears to have evolved in response to variation in the light environment across ecological niches across three species of box jellyfish (Chironex fleckeri, Chiropsella bronzie, and Carukia barnesi). Behavioral studies suggest that faster pupil contraction rates allow for greater object avoidance, and in fact, species with more complex habitats exhibit faster rates. Ch. bronzie inhabit shallow beach fronts that have low visibility and very few obstacles, thus, faster pupil contraction in response to objects in their environment is not important. Ca. barnesi and Ch. fleckeri are found in more three-dimensionally complex environments like mangroves with an abundance of natural obstacles, where faster pupil contraction is more adaptive. Behavioral studies support the idea that faster pupillary contraction rates assist with obstacle avoidance as well as depth adjustments in response to differing light intensities.

Light/dark adaptation via pupillary light reflexes is an additional form of an evolutionary response to the light environment. This relates to the pupil's response to shifts between light intensity (generally from sunlight to darkness). In the process of light/dark adaptation, the upper and lower lens eyes of different box jellyfish species vary in specific function. The lower lens-eyes contain pigmented photoreceptors and long pigment cells with dark pigments that migrate on light/dark adaptation, while the upper-lens eyes play a concentrated role in light direction and phototaxis given that they face upward towards the water surface (towards the sun or moon). The upper lens of Ch. bronzie does not exhibit any considerable optical power while Tr. cystophora (a box jellyfish species that tends to live in mangroves) does. The ability to use light to visually guide behavior is not of as much importance to Ch. bronzie as it is to species in more obstacle-filled environments. Differences in visually guided behavior serve as evidence that species that share the same number and structure of eyes can exhibit differences in how they control behavior.

Largest and smallest
Jellyfish range from about one millimeter in bell height and diameter, to nearly 2 metres (6+1⁄2 ft) in bell height and diameter; the tentacles and mouth parts usually extend beyond this bell dimension.

The smallest jellyfish are the peculiar creeping jellyfish in the genera Staurocladia and Eleutheria, which have bell disks from 0.5 millimetres (1⁄32 in) to a few millimeters in diameter, with short tentacles that extend out beyond this, which these jellyfish use to move across the surface of seaweed or the bottoms of rocky pools; many of these tiny creeping jellyfish cannot be seen in the field without a hand lens or microscope. They can reproduce asexually by fission (splitting in half). Other very small jellyfish, which have bells about one millimeter, are the hydromedusae of many species that have just been released from their parent polyps; some of these live only a few minutes before shedding their gametes in the plankton and then dying, while others will grow in the plankton for weeks or months. The hydromedusae Cladonema radiatum and Cladonema californicum are also very small, living for months, yet never growing beyond a few mm in bell height and diameter.

The lion's mane jellyfish, Cyanea capillata, was long-cited as the largest jellyfish, and arguably the longest animal in the world, with fine, thread-like tentacles that may extend up to 36.5 m (119 ft 9 in) long (though most are nowhere near that large). They have a moderately painful, but rarely fatal, sting. The increasingly common giant Nomura's jellyfish, Nemopilema nomurai, found in some, but not all years in the waters of Japan, Korea and China in summer and autumn is another candidate for "largest jellyfish", in terms of diameter and weight, since the largest Nomura's jellyfish in late autumn can reach 2 m (6 ft 7 in) in bell (body) diameter and about 200 kg (440 lb) in weight, with average specimens frequently reaching 0.9 m (2 ft 11 in) in bell diameter and about 150 kg (330 lb) in weight. The large bell mass of the giant Nomura's jellyfish can dwarf a diver and is nearly always much greater than the Lion's Mane, whose bell diameter can reach 1 m (3 ft 3 in).

The rarely encountered deep-sea jellyfish Stygiomedusa gigantea is another candidate for "largest jellyfish", with its thick, massive bell up to 100 cm (3 ft 3 in) wide, and four thick, "strap-like" oral arms extending up to 6 m (19+1⁄2 ft) in length, very different from the typical fine, threadlike tentacles that rim the umbrella of more-typical-looking jellyfish, including the Lion's Mane.

Desmonema glaciale, which lives in the Antarctic region, can reach a very large size (several meters). Purple-striped jelly (Chrysaora colorata) can also be extremely long (up to 15 feet).

Life history and behavior
Life cycle
Jellyfish have a complex life cycle which includes both sexual and asexual phases, with the medusa being the sexual stage in most instances. Sperm fertilize eggs, which develop into larval planulae, become polyps, bud into ephyrae and then transform into adult medusae. In some species certain stages may be skipped.

Upon reaching adult size, jellyfish spawn regularly if there is a sufficient supply of food. In most species, spawning is controlled by light, with all individuals spawning at about the same time of day; in many instances this is at dawn or dusk. Jellyfish are usually either male or female (with occasional hermaphrodites). In most cases, adults release sperm and eggs into the surrounding water, where the unprotected eggs are fertilized and develop into larvae. In a few species, the sperm swim into the female's mouth, fertilizing the eggs within her body, where they remain during early development stages. In moon jellies, the eggs lodge in pits on the oral arms, which form a temporary brood chamber for the developing planula larvae.

The planula is a small larva covered with cilia. When sufficiently developed, it settles onto a firm surface and develops into a polyp. The polyp generally consists of a small stalk topped by a mouth that is ringed by upward-facing tentacles. The polyps resemble those of closely related anthozoans, such as sea anemones and corals. The jellyfish polyp may be sessile, living on the bottom, boat hulls or other substrates, or it may be free-floating or attached to tiny bits of free-living plankton or rarely, fish or other invertebrates. Polyps may be solitary or colonial. Most polyps are only millimetres in diameter and feed continuously. The polyp stage may last for years.

After an interval and stimulated by seasonal or hormonal changes, the polyp may begin reproducing asexually by budding and, in the Scyphozoa, is called a segmenting polyp, or a scyphistoma. Budding produces more scyphistomae and also ephyrae. Budding sites vary by species; from the tentacle bulbs, the manubrium (above the mouth), or the gonads of hydromedusae. In a process known as strobilation, the polyp's tentacles are reabsorbed and the body starts to narrow, forming transverse constrictions, in several places near the upper extremity of the polyp. These deepen as the constriction sites migrate down the body, and separate segments known as ephyra detach. These are free-swimming precursors of the adult medusa stage, which is the life stage that is typically identified as a jellyfish. The ephyrae, usually only a millimeter or two across initially, swim away from the polyp and grow. Limnomedusae polyps can asexually produce a creeping frustule larval form, which crawls away before developing into another polyp. A few species can produce new medusae by budding directly from the medusan stage. Some hydromedusae reproduce by fission.

Lifespan
Little is known of the life histories of many jellyfish as the places on the seabed where the benthic forms of those species live have not been found. However, an asexually reproducing strobila form can sometimes live for several years, producing new medusae (ephyra larvae) each year.

An unusual species, Turritopsis dohrnii, formerly classified as Turritopsis nutricula, might be effectively immortal because of its ability under certain circumstances to transform from medusa back to the polyp stage, thereby escaping the death that typically awaits medusae post-reproduction if they have not otherwise been eaten by some other organism. So far this reversal has been observed only in the laboratory.

Locomotion
Jellyfish locomotion is highly efficient. Muscles in the jellylike bell contract, setting up a start vortex and propelling the animal. When the contraction ends, the bell recoils elastically, creating a stop vortex with no extra energy input.
Using the moon jelly Aurelia aurita as an example, jellyfish have been shown to be the most energy-efficient swimmers of all animals. They move through the water by radially expanding and contracting their bell-shaped bodies to push water behind them. They pause between the contraction and expansion phases to create two vortex rings. Muscles are used for the contraction of the body, which creates the first vortex and pushes the animal forward, but the mesoglea is so elastic that the expansion is powered exclusively by relaxing the bell, which releases the energy stored from the contraction. Meanwhile, the second vortex ring starts to spin faster, sucking water into the bell and pushing against the centre of the body, giving a secondary and "free" boost forward. The mechanism, called passive energy recapture, only works in relatively small jellyfish moving at low speeds, allowing the animal to travel 30 percent farther on each swimming cycle. Jellyfish achieved a 48 percent lower cost of transport (food and oxygen intake versus energy spent in movement) than other animals in similar studies. One reason for this is that most of the gelatinous tissue of the bell is inactive, using no energy during swimming.

Ecology
Diet
Jellyfish are, like other cnidarians, generally carnivorous (or parasitic), feeding on planktonic organisms, crustaceans, small fish, fish eggs and larvae, and other jellyfish, ingesting food and voiding undigested waste through the mouth. They hunt passively using their tentacles as drift lines, or sink through the water with their tentacles spread widely; the tentacles, which contain nematocysts to stun or kill the prey, may then flex to help bring it to the mouth. Their swimming technique also helps them to capture prey; when their bell expands it sucks in water which brings more potential prey within reach of the tentacles.

A few species such as Aglaura hemistoma are omnivorous, feeding on microplankton which is a mixture of zooplankton and phytoplankton (microscopic plants) such as dinoflagellates. Others harbour mutualistic algae (Zooxanthellae) in their tissues; the spotted jellyfish (Mastigias papua) is typical of these, deriving part of its nutrition from the products of photosynthesis, and part from captured zooplankton. The upside-down jellyfish (Cassiopea andromeda) also has a symbiotic relationship with microalgae, but captures tiny animals to supplement their diet. This is done by releasing tiny balls of living cells composed of mesoglea. These use cilia to drive them through water and stinging cells which stun the prey. The blobs also seems to have digestive capabilities.

Predation
Other species of jellyfish are among the most common and important jellyfish predators. Sea anemones may eat jellyfish that drift into their range. Other predators include tunas, sharks, swordfish, sea turtles and penguins. Jellyfish washed up on the beach are consumed by foxes, other terrestrial mammals and birds. In general however, few animals prey on jellyfish; they can broadly be considered to be top predators in the food chain. Once jellyfish have become dominant in an ecosystem, for example through overfishing which removes predators of jellyfish larvae, there may be no obvious way for the previous balance to be restored: they eat fish eggs and juvenile fish, and compete with fish for food, preventing fish stocks from recovering.

Symbiosis
Some small fish are immune to the stings of the jellyfish and live among the tentacles, serving as bait in a fish trap; they are safe from potential predators and are able to share the fish caught by the jellyfish. The cannonball jellyfish has a symbiotic relationship with ten different species of fish, and with the longnose spider crab, which lives inside the bell, sharing the jellyfish's food and nibbling its tissues.

Main article: Jellyfish bloom
Jellyfish form large masses or blooms in certain environmental conditions of ocean currents, nutrients, sunshine, temperature, season, prey availability, reduced predation and oxygen concentration. Currents collect jellyfish together, especially in years with unusually high populations. Jellyfish can detect marine currents and swim against the current to congregate in blooms. Jellyfish are better able to survive in nutrient-rich, oxygen-poor water than competitors, and thus can feast on plankton without competition. Jellyfish may also benefit from saltier waters, as saltier waters contain more iodine, which is necessary for polyps to turn into jellyfish. Rising sea temperatures caused by climate change may also contribute to jellyfish blooms, because many species of jellyfish are able to survive in warmer waters. Increased nutrients from agricultural or urban runoff with nutrients including nitrogen and phosphorus compounds increase the growth of phytoplankton, causing eutrophication and algal blooms. When the phytoplankton die, they may create dead zones, so-called because they are hypoxic (low in oxygen). This in turn kills fish and other animals, but not jellyfish, allowing them to bloom. Jellyfish populations may be expanding globally as a result of land runoff and overfishing of their natural predators. Jellyfish are well placed to benefit from disturbance of marine ecosystems. They reproduce rapidly; they prey upon many species, while few species prey on them; and they feed via touch rather than visually, so they can feed effectively at night and in turbid waters. It may be difficult for fish stocks to re-establish themselves in marine ecosystems once they have become dominated by jellyfish, because jellyfish feed on plankton, which includes fish eggs and larvae.

As suspected at the turn of this century, jellyfish blooms are increasing in frequency. Between 2013 and 2020 the Mediterranean Science Commission monitored on a weekly basis the frequency of such outbreaks in coastal waters from Morocco to the Black Sea, revealing a relatively high frequency of these blooms nearly all year round, with peaks observed from March to July and often again in the autumn. The blooms are caused by different jellyfish species, depending on their localisation within the Basin: one observes a clear dominance of Pelagia noctiluca and Velella velella outbreaks in the western Mediterranean, of Rhizostoma pulmo and Rhopilema nomadica outbreaks in the eastern Mediterranean, and of Aurelia aurita and Mnemiopsis leidyi outbreaks in the Black Sea.

Some jellyfish populations that have shown clear increases in the past few decades are invasive species, newly arrived from other habitats: examples include the Black Sea, Caspian Sea, Baltic Sea, central and eastern Mediterranean, Hawaii, and tropical and subtropical parts of the West Atlantic (including the Caribbean, Gulf of Mexico and Brazil).

Jellyfish blooms can have significant impact on community structure. Some carnivorous jellyfish species prey on zooplankton while others graze on primary producers. Reductions in zooplankton and ichthyoplankton due to a jellyfish bloom can ripple through the trophic levels. High-density jellyfish populations can outcompete other predators and reduce fish recruitment. Increased grazing on primary producers by jellyfish can also interrupt energy transfer to higher trophic levels.

During blooms, jellyfish significantly alter the nutrient availability in their environment. Blooms require large amounts of available organic nutrients in the water column to grow, limiting availability for other organisms. Some jellyfish have a symbiotic relationship with single-celled dinoflagellates, allowing them to assimilate inorganic carbon, phosphorus, and nitrogen creating competition for phytoplankton. Their large biomass makes them an important source of dissolved and particulate organic matter for microbial communities through excretion, mucus production, and decomposition. The microbes break down the organic matter into inorganic ammonium and phosphate. However, the low carbon availability shifts the process from production to respiration creating low oxygen areas making the dissolved inorganic nitrogen and phosphorus largely unavailable for primary production.

These blooms have very real impacts on industries. Jellyfish can outcompete fish by utilizing open niches in over-fished fisheries. Catch of jellyfish can strain fishing gear and lead to expenses relating to damaged gear. Power plants have been shut down due to jellyfish blocking the flow of cooling water. Blooms have also been harmful for tourism, causing a rise in stings and sometimes the closure of beaches.

Jellyfish form a component of jelly-falls, events where gelatinous zooplankton fall to the seafloor, providing food for the benthic organisms there. In temperate and subpolar regions, jelly-falls usually follow immediately after a bloom.

Habitats
Most jellyfish are marine animals, although a few hydromedusae inhabit freshwater. The best known freshwater example is the cosmopolitan hydrozoan jellyfish, Craspedacusta sowerbii. It is less than an inch (2.5 cm) in diameter, colorless and does not sting. Some jellyfish populations have become restricted to coastal saltwater lakes, such as Jellyfish Lake in Palau. Jellyfish Lake is a marine lake where millions of golden jellyfish (Mastigias spp.) migrate horizontally across the lake daily.

Although most jellyfish live well off the ocean floor and form part of the plankton, a few species are closely associated with the bottom for much of their lives and can be considered benthic. The upside-down jellyfish in the genus Cassiopea typically lie on the bottom of shallow lagoons where they sometimes pulsate gently with their umbrella top facing down. Even some deep-sea species of hydromedusae and scyphomedusae are usually collected on or near the bottom. All of the stauromedusae are found attached to either seaweed or rocky or other firm material on the bottom.

Some species explicitly adapt to tidal flux. In Roscoe Bay, jellyfish ride the current at ebb tide until they hit a gravel bar, and then descend below the current. They remain in still waters until the tide rises, ascending and allowing it to sweep them back into the bay. They also actively avoid fresh water from mountain snowmelt, diving until they find enough salt.


Parasites
Jellyfish are hosts to a wide variety of parasitic organisms. They act as intermediate hosts of endoparasitic helminths, with the infection being transferred to the definitive host fish after predation. Some digenean trematodes, especially species in the family Lepocreadiidae, use jellyfish as their second intermediate hosts. Fish become infected by the trematodes when they feed on infected jellyfish.

Relation to humans
Jellyfish have long been eaten in some parts of the world. Fisheries have begun harvesting the American cannonball jellyfish, Stomolophus meleagris, along the southern Atlantic coast of the United States and in the Gulf of Mexico for export to Asia.

Jellyfish are also harvested for their collagen, which is being investigated for use in a variety of applications including the treatment of rheumatoid arthritis.

Aquaculture and fisheries of other species often suffer severe losses – and so losses of productivity – due to jellyfish.

Products
Main article: Jellyfish as food
In some countries, including China, Japan, and Korea, jellyfish are a delicacy. The jellyfish is dried to prevent spoiling. Only some 12 species of scyphozoan jellyfish belonging to the order Rhizostomeae are harvested for food, mostly in southeast Asia. Rhizostomes, especially Rhopilema esculentum in China (海蜇 hǎizhé, 'sea stingers') and Stomolophus meleagris (cannonball jellyfish) in the United States, are favored because of their larger and more rigid bodies and because their toxins are harmless to humans.

Traditional processing methods, carried out by a jellyfish master, involve a 20- to 40-day multi-phase procedure in which, after removing the gonads and mucous membranes, the umbrella and oral arms are treated with a mixture of table salt and alum, and compressed. Processing makes the jellyfish drier and more acidic, producing a crisp texture. Jellyfish prepared this way retain 7–10% of their original weight, and the processed product consists of approximately 94% water and 6% protein. Freshly processed jellyfish has a white, creamy color and turns yellow or brown during prolonged storage.

In China, processed jellyfish are desalted by soaking in water overnight and eaten cooked or raw. The dish is often served shredded with a dressing of oil, soy sauce, vinegar and sugar, or as a salad with vegetables. In Japan, cured jellyfish are rinsed, cut into strips and served with vinegar as an appetizer. Desalted, ready-to-eat products are also available.

Biotechnology
The hydromedusa Aequorea victoria was the source of green fluorescent protein, studied for its role in bioluminescence and later for use as a marker in genetic engineering.
Pliny the Elder reported in his Natural History that the slime of the jellyfish "Pulmo marinus" produced light when rubbed on a walking stick.

In 1961, Osamu Shimomura extracted green fluorescent protein (GFP) and another bioluminescent protein, called aequorin, from the large and abundant hydromedusa Aequorea victoria, while studying photoproteins that cause bioluminescence in this species. Three decades later, Douglas Prasher sequenced and cloned the gene for GFP. Martin Chalfie figured out how to use GFP as a fluorescent marker of genes inserted into other cells or organisms. Roger Tsien later chemically manipulated GFP to produce other fluorescent colors to use as markers. In 2008, Shimomura, Chalfie and Tsien won the Nobel Prize in Chemistry for their work with GFP. Man-made GFP became widely used as a fluorescent tag to show which cells or tissues express specific genes. The genetic engineering technique fuses the gene of interest to the GFP gene. The fused DNA is then put into a cell, to generate either a cell line or (via IVF techniques) an entire animal bearing the gene. In the cell or animal, the artificial gene turns on in the same tissues and the same time as the normal gene, making a fusion of the normal protein with GFP attached to the end, illuminating the animal or cell reveals what tissues express that protein—or at what stage of development. The fluorescence shows where the gene is expressed.

Aquarium display
Jellyfish are displayed in many public aquariums. Often the tank's background is blue and the animals are illuminated by side light, increasing the contrast between the animal and the background. In natural conditions, many jellies are so transparent that they are nearly invisible. Jellyfish are not adapted to closed spaces. They depend on currents to transport them from place to place. Professional exhibits as in the Monterey Bay Aquarium feature precise water flows, typically in circular tanks to avoid trapping specimens in corners. The outflow is spread out over a large surface area and the inflow enters as a sheet of water in front of the outflow, so the jellyfish do not get sucked into it. As of 2009, jellyfish were becoming popular in home aquariums, where they require similar equipment.

Stings
Jellyfish are armed with nematocysts, a type of specialized stinging cell. Contact with a jellyfish tentacle can trigger millions of nematocysts to pierce the skin and inject venom, but only some species' venom causes an adverse reaction in humans. In a study published in Communications Biology, researchers found a jellyfish species called Cassiopea xamachana which when triggered will release tiny balls of cells that swim around the jellyfish stinging everything in their path. Researchers described these as "self-propelling microscopic grenades" and named them cassiosomes.

The effects of stings range from mild discomfort to extreme pain and death. Most jellyfish stings are not deadly, but stings of some box jellyfish (Irukandji jellyfish), such as the sea wasp, can be deadly. Stings may cause anaphylaxis (a form of shock), which can be fatal. Jellyfish kill 20 to 40 people a year in the Philippines alone. In 2006 the Spanish Red Cross treated 19,000 stung swimmers along the Costa Brava.

Vinegar (3–10% aqueous acetic acid) may help with box jellyfish stings but not the stings of the Portuguese man o' war. Clearing the area of jelly and tentacles reduces nematocyst firing. Scraping the affected skin, such as with the edge of a credit card, may remove remaining nematocysts. Once the skin has been cleaned of nematocysts, hydrocortisone cream applied locally reduces pain and inflammation. Antihistamines may help to control itching. Immunobased antivenins are used for serious box jellyfish stings.

In Elba Island and Corsica dittrichia viscosa is now used by residents and tourists to heal stings from jellyfish, bees and wasps pressing fresh leaves on the skin with quick results.

Mechanical issues
Jellyfish in large quantities can fill and split fishing nets and crush captured fish. They can clog cooling equipment, having disabled power stations in several countries; jellyfish caused a cascading blackout in the Philippines in 1999, as well as damaging the Diablo Canyon Power Plant in California in 2008. They can also stop desalination plants and ships' engines.

Jellyfish - Sea Jellies - Medusa (Subphylum Medusozoa) by millicand@rocketmail.com

© millicand@rocketmail.com, all rights reserved.

Jellyfish - Sea Jellies - Medusa (Subphylum Medusozoa)

Jellyfish, also known sea jellies, are the medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria.

Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles, although a few are anchored to the seabed by stalks rather than being mobile. The bell can pulsate to provide propulsion for highly efficient locomotion. The tentacles are armed with stinging cells and may be used to capture prey and defend against predators. Jellyfish have a complex life cycle. The medusa is normally the sexual phase, which produces planula larvae; these then disperse widely and enter a sedentary polyp phase, before reaching sexual maturity.

Jellyfish are found all over the world, from surface waters to the deep sea. Scyphozoans (the "true jellyfish") are exclusively marine, but some hydrozoans with a similar appearance live in freshwater. Large, often colorful, jellyfish are common in coastal zones worldwide. The medusae of most species are fast-growing, and mature within a few months then die soon after breeding, but the polyp stage, attached to the seabed, may be much more long-lived. Jellyfish have been in existence for at least 500 million years,[1] and possibly 700 million years or more, making them the oldest multi-organ animal group.[2]

Jellyfish are eaten by humans in certain cultures. They are considered a delicacy in some Asian countries, where species in the Rhizostomeae order are pressed and salted to remove excess water. Australian researchers have described them as a "perfect food": sustainable and protein-rich but relatively low in food energy.[3]

They are also used in research, where the green fluorescent protein used by some species to cause bioluminescence has been adapted as a fluorescent marker for genes inserted into other cells or organisms.

The stinging cells used by jellyfish to subdue their prey can injure humans. Thousands of swimmers worldwide are stung every year, with effects ranging from mild discomfort to serious injury or even death. When conditions are favourable, jellyfish can form vast swarms, which can be responsible for damage to fishing gear by filling fishing nets, and sometimes clog the cooling systems of power and desalination plants which draw their water from the sea.


Names
The name jellyfish, in use since 1796,[4] has traditionally been applied to medusae and all similar animals including the comb jellies (ctenophores, another phylum).[5][6] The term jellies or sea jellies is more recent, having been introduced by public aquaria in an effort to avoid use of the word "fish" with its modern connotation of an animal with a backbone, though shellfish, cuttlefish and starfish are not vertebrates either.[7][8] In scientific literature, "jelly" and "jellyfish" have been used interchangeably.[9][10] Many sources refer to only scyphozoans as "true jellyfish".[11]

A group of jellyfish is called a "smack"[12] or a "smuck".[13]

Mapping to taxonomic groups

A purple-striped jellyfish at the Monterey Bay Aquarium
Phylogeny
Definition
The term jellyfish broadly corresponds to medusae,[4] that is, a life-cycle stage in the Medusozoa. The American evolutionary biologist Paulyn Cartwright gives the following general definition:

Typically, medusozoan cnidarians have a pelagic, predatory jellyfish stage in their life cycle; staurozoans are the exceptions [as they are stalked].[14]

The Merriam-Webster dictionary defines jellyfish as follows:

A free-swimming marine coelenterate that is the sexually reproducing form of a hydrozoan or scyphozoan and has a nearly transparent saucer-shaped body and extensible marginal tentacles studded with stinging cells.[15]

Given that jellyfish is a common name, its mapping to biological groups is inexact. Some authorities have called the comb jellies[16] and certain salps[16] jellyfish, though other authorities state that neither of these are jellyfish, which they consider should be limited to certain groups within the medusozoa.[17][18]

The non-medusozoan clades called jellyfish by some but not all authorities (both agreeing and disagreeing citations are given in each case) are indicated with "???" on the following cladogram of the animal kingdom:

Animalia
Porifera

Ctenophora (comb jellies)[16] ???[17]

Cnidaria (includes jellyfish and other jellies)

Bilateria
Protostomia

Deuterostomia
Ambulacraria

Chordata
Tunicata (includes salps)[16] ???[18]

Vertebrata

Medusozoan jellyfish
Jellyfish are not a clade, as they include most of the Medusozoa, barring some of the Hydrozoa.[19][20] The medusozoan groups included by authorities are indicated on the following phylogenetic tree by the presence of citations. Names of included jellyfish, in English where possible, are shown in boldface; the presence of a named and cited example indicates that at least that species within its group has been called a jellyfish.

Cnidaria
Anthozoa (corals)

Polypodiozoa and Myxozoa (parasitic cnidarians)

Medusozoa
Acraspeda
Staurozoa (stalked jellyfish)[21]

Rhopaliophora
Cubozoa (box jellyfish)[16]

Scyphozoa
Discomedusae[16]

Coronatae (crown jellyfish)[22]

(true jellyfish[19])
Hydrozoa
Aplanulata

Siphonophorae

Some Leptothecata[16] e.g. crystal jelly

Filifera[16] e.g. red paper lantern jellyfish[23]

Trachylinae
Limnomedusae, e.g. flower hat jelly[16]

Narcomedusae, e.g. cosmic jellyfish[24]

Taxonomy
The subphylum Medusozoa includes all cnidarians with a medusa stage in their life cycle. The basic cycle is egg, planula larva, polyp, medusa, with the medusa being the sexual stage. The polyp stage is sometimes secondarily lost. The subphylum include the major taxa, Scyphozoa (large jellyfish), Cubozoa (box jellyfish) and Hydrozoa (small jellyfish), and excludes Anthozoa (corals and sea anemones).[25] This suggests that the medusa form evolved after the polyps.[26] Medusozoans have tetramerous symmetry, with parts in fours or multiples of four.[25]

The four major classes of medusozoan Cnidaria are:

Scyphozoa are sometimes called true jellyfish, though they are no more truly jellyfish than the others listed here. They have tetra-radial symmetry. Most have tentacles around the outer margin of the bowl-shaped bell, and long, oral arms around the mouth in the center of the subumbrella.[25]
Cubozoa (box jellyfish) have a (rounded) box-shaped bell, and their velarium assists them to swim more quickly. Box jellyfish may be related more closely to scyphozoan jellyfish than either are to the Hydrozoa.[26]
Hydrozoa medusae also have tetra-radial symmetry, nearly always have a velum (diaphragm used in swimming) attached just inside the bell margin, do not have oral arms, but a much smaller central stalk-like structure, the manubrium, with terminal mouth opening, and are distinguished by the absence of cells in the mesoglea. Hydrozoa show great diversity of lifestyle; some species maintain the polyp form for their entire life and do not form medusae at all (such as Hydra, which is hence not considered a jellyfish), and a few are entirely medusal and have no polyp form.[25]
Staurozoa (stalked jellyfish) are characterized by a medusa form that is generally sessile, oriented upside down and with a stalk emerging from the apex of the "calyx" (bell), which attaches to the substrate. At least some Staurozoa also have a polyp form that alternates with the medusoid portion of the life cycle. Until recently, Staurozoa were classified within the Scyphozoa.[25]
There are over 200 species of Scyphozoa, about 50 species of Staurozoa, about 50 species of Cubozoa, and the Hydrozoa includes about 1000–1500 species that produce medusae, but many more species that do not.[27][28]

Fossil history

Fossil jellyfish, Rhizostomites lithographicus, one of the Scypho-medusae, from the Kimmeridgian (late Jurassic, 157 to 152 mya) of Solnhofen, Germany

Stranded scyphozoans on a Cambrian tidal flat at Blackberry Hill, Wisconsin

The conulariid Conularia milwaukeensis from the Middle Devonian of Wisconsin
Since jellyfish have no hard parts, fossils are rare. The oldest unambiguous fossil of a free-swimming medusa is Burgessomedusa from the mid Cambrian Burgess Shale of Canada, which is likely either a stem group of box jellyfish (Cubozoa) or Acraspeda (the clade including Staurozoa, Cubozoa, and Scyphozoa). Other claimed records from the Cambrian of China and Utah in the United States are uncertain, and possibly represent ctenophores instead.[29]

Anatomy

Labelled cross section of a jellyfish
The main feature of a true jellyfish is the umbrella-shaped bell. This is a hollow structure consisting of a mass of transparent jelly-like matter known as mesoglea, which forms the hydrostatic skeleton of the animal.[25] 95% or more of the mesogloea consists of water,[30] but it also contains collagen and other fibrous proteins, as well as wandering amoebocytes which can engulf debris and bacteria. The mesogloea is bordered by the epidermis on the outside and the gastrodermis on the inside. The edge of the bell is often divided into rounded lobes known as lappets, which allow the bell to flex. In the gaps or niches between the lappets are dangling rudimentary sense organs known as rhopalia, and the margin of the bell often bears tentacles.[25]


Anatomy of a scyphozoan jellyfish
On the underside of the bell is the manubrium, a stalk-like structure hanging down from the centre, with the mouth, which also functions as the anus, at its tip. There are often four oral arms connected to the manubrium, streaming away into the water below.[31] The mouth opens into the gastrovascular cavity, where digestion takes place and nutrients are absorbed. This is subdivided by four thick septa into a central stomach and four gastric pockets. The four pairs of gonads are attached to the septa, and close to them four septal funnels open to the exterior, perhaps supplying good oxygenation to the gonads. Near the free edges of the septa, gastric filaments extend into the gastric cavity; these are armed with nematocysts and enzyme-producing cells and play a role in subduing and digesting the prey. In some scyphozoans, the gastric cavity is joined to radial canals which branch extensively and may join a marginal ring canal. Cilia in these canals circulate the fluid in a regular direction.[25]


Discharge mechanism of a nematocyst
The box jellyfish is largely similar in structure. It has a squarish, box-like bell. A short pedalium or stalk hangs from each of the four lower corners. One or more long, slender tentacles are attached to each pedalium.[32] The rim of the bell is folded inwards to form a shelf known as a velarium which restricts the bell's aperture and creates a powerful jet when the bell pulsates, allowing box jellyfish to swim faster than true jellyfish.[25] Hydrozoans are also similar, usually with just four tentacles at the edge of the bell, although many hydrozoans are colonial and may not have a free-living medusal stage. In some species, a non-detachable bud known as a gonophore is formed that contains a gonad but is missing many other medusal features such as tentacles and rhopalia.[25] Stalked jellyfish are attached to a solid surface by a basal disk, and resemble a polyp, the oral end of which has partially developed into a medusa with tentacle-bearing lobes and a central manubrium with four-sided mouth.[25]

Most jellyfish do not have specialized systems for osmoregulation, respiration and circulation, and do not have a central nervous system. Nematocysts, which deliver the sting, are located mostly on the tentacles; true jellyfish also have them around the mouth and stomach.[33] Jellyfish do not need a respiratory system because sufficient oxygen diffuses through the epidermis. They have limited control over their movement, but can navigate with the pulsations of the bell-like body; some species are active swimmers most of the time, while others largely drift.[34] The rhopalia contain rudimentary sense organs which are able to detect light, water-borne vibrations, odour and orientation.[25] A loose network of nerves called a "nerve net" is located in the epidermis.[35][36] Although traditionally thought not to have a central nervous system, nerve net concentration and ganglion-like structures could be considered to constitute one in most species.[37] A jellyfish detects stimuli, and transmits impulses both throughout the nerve net and around a circular nerve ring, to other nerve cells. The rhopalial ganglia contain pacemaker neurones which control swimming rate and direction.[25]

In many species of jellyfish, the rhopalia include ocelli, light-sensitive organs able to tell light from dark. These are generally pigment spot ocelli, which have some of their cells pigmented. The rhopalia are suspended on stalks with heavy crystals at one end, acting like gyroscopes to orient the eyes skyward. Certain jellyfish look upward at the mangrove canopy while making a daily migration from mangrove swamps into the open lagoon, where they feed, and back again.[2]

Box jellyfish have more advanced vision than the other groups. Each individual has 24 eyes, two of which are capable of seeing colour, and four parallel information processing areas that act in competition,[38] supposedly making them one of the few kinds of animal to have a 360-degree view of its environment.[39]

Box jellyfish eye
The study of jellyfish eye evolution is an intermediary to a better understanding of how visual systems evolved on Earth.[40] Jellyfish exhibit immense variation in visual systems ranging from photoreceptive cell patches seen in simple photoreceptive systems to more derived complex eyes seen in box jellyfish.[40] Major topics of jellyfish visual system research (with an emphasis on box jellyfish) include: the evolution of jellyfish vision from simple to complex visual systems), the eye morphology and molecular structures of box jellyfish (including comparisons to vertebrate eyes), and various uses of vision including task-guided behaviors and niche specialization.

Evolution
Experimental evidence for photosensitivity and photoreception in cnidarians antecedes the mid 1900s, and a rich body of research has since covered evolution of visual systems in jellyfish.[41] Jellyfish visual systems range from simple photoreceptive cells to complex image-forming eyes. More ancestral visual systems incorporate extraocular vision (vision without eyes) that encompass numerous receptors dedicated to single-function behaviors. More derived visual systems comprise perception that is capable of multiple task-guided behaviors.

Although they lack a true brain, cnidarian jellyfish have a "ring" nervous system that plays a significant role in motor and sensory activity. This net of nerves is responsible for muscle contraction and movement and culminates the emergence of photosensitive structures.[40] Across Cnidaria, there is large variation in the systems that underlie photosensitivity. Photosensitive structures range from non-specialized groups of cells, to more "conventional" eyes similar to those of vertebrates.[41] The general evolutionary steps to develop complex vision include (from more ancestral to more derived states): non-directional photoreception, directional photoreception, low-resolution vision, and high-resolution vision.[40] Increased habitat and task complexity has favored the high-resolution visual systems common in derived cnidarians such as box jellyfish.[40]

Basal visual systems observed in various cnidarians exhibit photosensitivity representative of a single task or behavior. Extraocular photoreception (a form of non-directional photoreception), is the most basic form of light sensitivity and guides a variety of behaviors among cnidarians. It can function to regulate circadian rhythm (as seen in eyeless hydrozoans) and other light-guided behaviors responsive to the intensity and spectrum of light. Extraocular photoreception can function additionally in positive phototaxis (in planula larvae of hydrozoans),[41] as well as in avoiding harmful amounts of UV radiation via negative phototaxis. Directional photoreception (the ability to perceive direction of incoming light) allows for more complex phototactic responses to light, and likely evolved by means of membrane stacking.[40] The resulting behavioral responses can range from guided spawning events timed by moonlight to shadow responses for potential predator avoidance.[41][42] Light-guided behaviors are observed in numerous scyphozoans including the common moon jelly, Aurelia aurita, which migrates in response to changes in ambient light and solar position even though they lack proper eyes.[41]

The low-resolution visual system of box jellyfish is more derived than directional photoreception, and thus box jellyfish vision represents the most basic form of true vision in which multiple directional photoreceptors combine to create the first imaging and spatial resolution. This is different from the high-resolution vision that is observed in camera or compound eyes of vertebrates and cephalopods that rely on focusing optics.[41] Critically, the visual systems of box jellyfish are responsible for guiding multiple tasks or behaviors in contrast to less derived visual systems in other jellyfish that guide single behavioral functions. These behaviors include phototaxis based on sunlight (positive) or shadows (negative), obstacle avoidance, and control of swim-pulse rate.[43]

Box jellyfish possess "proper eyes" (similar to vertebrates) that allow them to inhabit environments that lesser derived medusae cannot. In fact, they are considered the only class in the clade Medusozoa that have behaviors necessitating spatial resolution and genuine vision.[41] However, the lens in their eyes are more functionally similar to cup-eyes exhibited in low-resolution organisms, and have very little to no focusing capability.[44][43] The lack of the ability to focus is due to the focal length exceeding the distance to the retina, thus generating unfocused images and limiting spatial resolution.[41] The visual system is still sufficient for box jellyfish to produce an image to help with tasks such as object avoidance.

Utility as a model organism
Box jellyfish eyes are a visual system that is sophisticated in numerous ways. These intricacies include the considerable variation within the morphology of box jellyfishes' eyes (including their task/behavior specification), and the molecular makeup of their eyes including: photoreceptors, opsins, lenses, and synapses.[41] The comparison of these attributes to more derived visual systems can allow for a further understanding of how the evolution of more derived visual systems may have occurred, and puts into perspective how box jellyfish can play the role as an evolutionary/developmental model for all visual systems.[45]

Characteristics
Box jellyfish visual systems are both diverse and complex, comprising multiple photosystems.[41] There is likely considerable variation in visual properties between species of box jellyfish given the significant inter-species morphological and physiological variation. Eyes tend to differ in size and shape, along with number of receptors (including opsins), and physiology across species of box jellyfish.[41]

Box jellyfish have a series of intricate lensed eyes that are similar to those of more derived multicellular organisms such as vertebrates. Their 24 eyes fit into four different morphological categories.[46] These categories consist of two large, morphologically different medial eyes (a lower and upper lensed eye) containing spherical lenses, a lateral pair of pigment slit eyes, and a lateral pair of pigment pit eyes.[43] The eyes are situated on rhopalia (small sensory structures) which serve sensory functions of the box jellyfish and arise from the cavities of the exumbrella (the surface of the body) on the side of the bells of the jellyfish.[41] The two large eyes are located on the mid-line of the club and are considered complex because they contain lenses. The four remaining eyes lie laterally on either side of each rhopalia and are considered simple. The simple eyes are observed as small invaginated cups of epithelium that have developed pigmentation.[47] The larger of the complex eyes contains a cellular cornea created by a mono ciliated epithelium, cellular lens, homogenous capsule to the lens, vitreous body with prismatic elements, and a retina of pigmented cells. The smaller of the complex eyes is said to be slightly less complex given that it lacks a capsule but otherwise contains the same structure as the larger eye.[47]

Box jellyfish have multiple photosystems that comprise different sets of eyes.[41] Evidence includes immunocytochemical and molecular data that show photopigment differences among the different morphological eye types, and physiological experiments done on box jellyfish to suggest behavioral differences among photosystems. Each individual eye type constitutes photosystems that work collectively to control visually guided behaviors.[41]

Box jellyfish eyes primarily use c-PRCs (ciliary photoreceptor cells) similar to that of vertebrate eyes. These cells undergo phototransduction cascades (process of light absorption by photoreceptors) that are triggered by c-opsins.[48] Available opsin sequences suggest that there are two types of opsins possessed by all cnidarians including an ancient phylogenetic opsin, and a sister ciliary opsin to the c-opsins group. Box jellyfish could have both ciliary and cnidops (cnidarian opsins), which is something not previously believed to appear in the same retina.[41] Nevertheless, it is not entirely evident whether cnidarians possess multiple opsins that are capable of having distinctive spectral sensitivities.[41]

Comparison with other organisms
Comparative research on genetic and molecular makeup of box jellyfishes' eyes versus more derived eyes seen in vertebrates and cephalopods focuses on: lenses and crystallin composition, synapses, and Pax genes and their implied evidence for shared primordial (ancestral) genes in eye evolution.[49]

Box jellyfish eyes are said to be an evolutionary/developmental model of all eyes based on their evolutionary recruitment of crystallins and Pax genes.[45] Research done on box jellyfish including Tripedalia cystophora has suggested that they possess a single Pax gene, PaxB. PaxB functions by binding to crystallin promoters and activating them. PaxB in situ hybridization resulted in PaxB expression in the lens, retina, and statocysts.[45] These results and the rejection of the prior hypothesis that Pax6 was an ancestral Pax gene in eyes has led to the conclusion that PaxB was a primordial gene in eye evolution, and that the eyes of all organisms likely share a common ancestor.[45]

The lens structure of box jellyfish appears very similar to those of other organisms, but the crystallins are distinct in both function and appearance.[49] Weak reactions were seen within the sera and there were very weak sequence similarities within the crystallins among vertebrate and invertebrate lenses.[49] This is likely due to differences in lower molecular weight proteins and the subsequent lack of immunological reactions with antisera that other organisms' lenses exhibit.[49]

All four of the visual systems of box jellyfish species investigated with detail (Carybdea marsupialis, Chiropsalmus quadrumanus, Tamoya haplonema and Tripedalia cystophora) have invaginated synapses, but only in the upper and lower lensed eyes. Different densities were found between the upper and lower lenses, and between species.[46] Four types of chemical synapses have been discovered within the rhopalia which could help in understanding neural organization including: clear unidirectional, dense-core unidirectional, clear bidirectional, and clear and dense-core bidirectional. The synapses of the lensed eyes could be useful as markers to learn more about the neural circuit in box jellyfish retinal areas.[46]

Evolution as a response to natural stimuli
The primary adaptive responses to environmental variation observed in box jellyfish eyes include pupillary constriction speeds in response to light environments, as well as photoreceptor tuning and lens adaptations to better respond to shifts between light environments and darkness. Interestingly, some box jellyfish species' eyes appear to have evolved more focused vision in response to their habitat.[50]

Pupillary contraction appears to have evolved in response to variation in the light environment across ecological niches across three species of box jellyfish (Chironex fleckeri, Chiropsella bronzie, and Carukia barnesi). Behavioral studies suggest that faster pupil contraction rates allow for greater object avoidance,[50] and in fact, species with more complex habitats exhibit faster rates. Ch. bronzie inhabit shallow beach fronts that have low visibility and very few obstacles, thus, faster pupil contraction in response to objects in their environment is not important. Ca. barnesi and Ch. fleckeri are found in more three-dimensionally complex environments like mangroves with an abundance of natural obstacles, where faster pupil contraction is more adaptive.[50] Behavioral studies support the idea that faster pupillary contraction rates assist with obstacle avoidance as well as depth adjustments in response to differing light intensities.

Light/dark adaptation via pupillary light reflexes is an additional form of an evolutionary response to the light environment. This relates to the pupil's response to shifts between light intensity (generally from sunlight to darkness). In the process of light/dark adaptation, the upper and lower lens eyes of different box jellyfish species vary in specific function.[43] The lower lens-eyes contain pigmented photoreceptors and long pigment cells with dark pigments that migrate on light/dark adaptation, while the upper-lens eyes play a concentrated role in light direction and phototaxis given that they face upward towards the water surface (towards the sun or moon).[43] The upper lens of Ch. bronzie does not exhibit any considerable optical power while Tr. cystophora (a box jellyfish species that tends to live in mangroves) does. The ability to use light to visually guide behavior is not of as much importance to Ch. bronzie as it is to species in more obstacle-filled environments.[43] Differences in visually guided behavior serve as evidence that species that share the same number and structure of eyes can exhibit differences in how they control behavior.

Largest and smallest
Jellyfish range from about one millimeter in bell height and diameter,[51] to nearly 2 metres (6+1⁄2 ft) in bell height and diameter; the tentacles and mouth parts usually extend beyond this bell dimension.[25]

The smallest jellyfish are the peculiar creeping jellyfish in the genera Staurocladia and Eleutheria, which have bell disks from 0.5 millimetres (1⁄32 in) to a few millimeters in diameter, with short tentacles that extend out beyond this, which these jellyfish use to move across the surface of seaweed or the bottoms of rocky pools;[51] many of these tiny creeping jellyfish cannot be seen in the field without a hand lens or microscope. They can reproduce asexually by fission (splitting in half). Other very small jellyfish, which have bells about one millimeter, are the hydromedusae of many species that have just been released from their parent polyps;[52] some of these live only a few minutes before shedding their gametes in the plankton and then dying, while others will grow in the plankton for weeks or months. The hydromedusae Cladonema radiatum and Cladonema californicum are also very small, living for months, yet never growing beyond a few mm in bell height and diameter.[53]


The lion's mane jellyfish (Cyanea capillata) is one of the largest species.
The lion's mane jellyfish, Cyanea capillata, was long-cited as the largest jellyfish, and arguably the longest animal in the world, with fine, thread-like tentacles that may extend up to 36.5 m (119 ft 9 in) long (though most are nowhere near that large).[54][55] They have a moderately painful, but rarely fatal, sting.[56] The increasingly common giant Nomura's jellyfish, Nemopilema nomurai, found in some, but not all years in the waters of Japan, Korea and China in summer and autumn is another candidate for "largest jellyfish", in terms of diameter and weight, since the largest Nomura's jellyfish in late autumn can reach 2 m (6 ft 7 in) in bell (body) diameter and about 200 kg (440 lb) in weight, with average specimens frequently reaching 0.9 m (2 ft 11 in) in bell diameter and about 150 kg (330 lb) in weight.[57][58] The large bell mass of the giant Nomura's jellyfish[59] can dwarf a diver and is nearly always much greater than the Lion's Mane, whose bell diameter can reach 1 m (3 ft 3 in).[60]

The rarely encountered deep-sea jellyfish Stygiomedusa gigantea is another candidate for "largest jellyfish", with its thick, massive bell up to 100 cm (3 ft 3 in) wide, and four thick, "strap-like" oral arms extending up to 6 m (19+1⁄2 ft) in length, very different from the typical fine, threadlike tentacles that rim the umbrella of more-typical-looking jellyfish, including the Lion's Mane.[61]

Desmonema glaciale, which lives in the Antarctic region, can reach a very large size (several meters).[62][63] Purple-striped jelly (Chrysaora colorata) can also be extremely long (up to 15 feet).[64]

Life history and behavior
See also: Biological life cycle and Developmental biology
Illustration of two life stages of seven jelly species
The developmental stages of scyphozoan jellyfish's life cycle:
1–3 Larva searches for site
4–8 Polyp grows
9–11 Polyp strobilates
12–14 Medusa grows
Life cycle
Jellyfish have a complex life cycle which includes both sexual and asexual phases, with the medusa being the sexual stage in most instances. Sperm fertilize eggs, which develop into larval planulae, become polyps, bud into ephyrae and then transform into adult medusae. In some species certain stages may be skipped.[65]

Upon reaching adult size, jellyfish spawn regularly if there is a sufficient supply of food. In most species, spawning is controlled by light, with all individuals spawning at about the same time of day; in many instances this is at dawn or dusk.[66] Jellyfish are usually either male or female (with occasional hermaphrodites). In most cases, adults release sperm and eggs into the surrounding water, where the unprotected eggs are fertilized and develop into larvae. In a few species, the sperm swim into the female's mouth, fertilizing the eggs within her body, where they remain during early development stages. In moon jellies, the eggs lodge in pits on the oral arms, which form a temporary brood chamber for the developing planula larvae.[67]

The planula is a small larva covered with cilia. When sufficiently developed, it settles onto a firm surface and develops into a polyp. The polyp generally consists of a small stalk topped by a mouth that is ringed by upward-facing tentacles. The polyps resemble those of closely related anthozoans, such as sea anemones and corals. The jellyfish polyp may be sessile, living on the bottom, boat hulls or other substrates, or it may be free-floating or attached to tiny bits of free-living plankton[68] or rarely, fish[69][70] or other invertebrates. Polyps may be solitary or colonial.[71] Most polyps are only millimetres in diameter and feed continuously. The polyp stage may last for years.[25]

After an interval and stimulated by seasonal or hormonal changes, the polyp may begin reproducing asexually by budding and, in the Scyphozoa, is called a segmenting polyp, or a scyphistoma. Budding produces more scyphistomae and also ephyrae.[25] Budding sites vary by species; from the tentacle bulbs, the manubrium (above the mouth), or the gonads of hydromedusae.[68] In a process known as strobilation, the polyp's tentacles are reabsorbed and the body starts to narrow, forming transverse constrictions, in several places near the upper extremity of the polyp. These deepen as the constriction sites migrate down the body, and separate segments known as ephyra detach. These are free-swimming precursors of the adult medusa stage, which is the life stage that is typically identified as a jellyfish.[25][72] The ephyrae, usually only a millimeter or two across initially, swim away from the polyp and grow. Limnomedusae polyps can asexually produce a creeping frustule larval form, which crawls away before developing into another polyp.[25] A few species can produce new medusae by budding directly from the medusan stage. Some hydromedusae reproduce by fission.[68]

Lifespan
Little is known of the life histories of many jellyfish as the places on the seabed where the benthic forms of those species live have not been found. However, an asexually reproducing strobila form can sometimes live for several years, producing new medusae (ephyra larvae) each year.[73]

An unusual species, Turritopsis dohrnii, formerly classified as Turritopsis nutricula,[74] might be effectively immortal because of its ability under certain circumstances to transform from medusa back to the polyp stage, thereby escaping the death that typically awaits medusae post-reproduction if they have not otherwise been eaten by some other organism. So far this reversal has been observed only in the laboratory.[75]

Locomotion

Jellyfish locomotion is highly efficient. Muscles in the jellylike bell contract, setting up a start vortex and propelling the animal. When the contraction ends, the bell recoils elastically, creating a stop vortex with no extra energy input.
Using the moon jelly Aurelia aurita as an example, jellyfish have been shown to be the most energy-efficient swimmers of all animals.[76] They move through the water by radially expanding and contracting their bell-shaped bodies to push water behind them. They pause between the contraction and expansion phases to create two vortex rings. Muscles are used for the contraction of the body, which creates the first vortex and pushes the animal forward, but the mesoglea is so elastic that the expansion is powered exclusively by relaxing the bell, which releases the energy stored from the contraction. Meanwhile, the second vortex ring starts to spin faster, sucking water into the bell and pushing against the centre of the body, giving a secondary and "free" boost forward. The mechanism, called passive energy recapture, only works in relatively small jellyfish moving at low speeds, allowing the animal to travel 30 percent farther on each swimming cycle. Jellyfish achieved a 48 percent lower cost of transport (food and oxygen intake versus energy spent in movement) than other animals in similar studies. One reason for this is that most of the gelatinous tissue of the bell is inactive, using no energy during swimming.[77]

Ecology
Diet
Jellyfish are, like other cnidarians, generally carnivorous (or parasitic),[78] feeding on planktonic organisms, crustaceans, small fish, fish eggs and larvae, and other jellyfish, ingesting food and voiding undigested waste through the mouth. They hunt passively using their tentacles as drift lines, or sink through the water with their tentacles spread widely; the tentacles, which contain nematocysts to stun or kill the prey, may then flex to help bring it to the mouth.[25] Their swimming technique also helps them to capture prey; when their bell expands it sucks in water which brings more potential prey within reach of the tentacles.[79]

A few species such as Aglaura hemistoma are omnivorous, feeding on microplankton which is a mixture of zooplankton and phytoplankton (microscopic plants) such as dinoflagellates.[80] Others harbour mutualistic algae (Zooxanthellae) in their tissues;[25] the spotted jellyfish (Mastigias papua) is typical of these, deriving part of its nutrition from the products of photosynthesis, and part from captured zooplankton.[81][82] The upside-down jellyfish (Cassiopea andromeda) also has a symbiotic relationship with microalgae, but captures tiny animals to supplement their diet. This is done by releasing tiny balls of living cells composed of mesoglea. These use cilia to drive them through water and stinging cells which stun the prey. The blobs also seems to have digestive capabilities.[83]

Predation
Other species of jellyfish are among the most common and important jellyfish predators. Sea anemones may eat jellyfish that drift into their range. Other predators include tunas, sharks, swordfish, sea turtles and penguins.[84][85] Jellyfish washed up on the beach are consumed by foxes, other terrestrial mammals and birds.[86] In general however, few animals prey on jellyfish; they can broadly be considered to be top predators in the food chain. Once jellyfish have become dominant in an ecosystem, for example through overfishing which removes predators of jellyfish larvae, there may be no obvious way for the previous balance to be restored: they eat fish eggs and juvenile fish, and compete with fish for food, preventing fish stocks from recovering.[87]

Symbiosis
Some small fish are immune to the stings of the jellyfish and live among the tentacles, serving as bait in a fish trap; they are safe from potential predators and are able to share the fish caught by the jellyfish.[88] The cannonball jellyfish has a symbiotic relationship with ten different species of fish, and with the longnose spider crab, which lives inside the bell, sharing the jellyfish's food and nibbling its tissues.[89]

Blooms
Main article: Jellyfish bloom

Map of population trends of native and invasive jellyfish.[90]
Circles represent data records; larger circles denote higher certainty of findings.
Increase (high certainty)
Increase (low certainty)
Stable/variable
Decrease
No data
Jellyfish form large masses or blooms in certain environmental conditions of ocean currents, nutrients, sunshine, temperature, season, prey availability, reduced predation and oxygen concentration. Currents collect jellyfish together, especially in years with unusually high populations. Jellyfish can detect marine currents and swim against the current to congregate in blooms.[91][92] Jellyfish are better able to survive in nutrient-rich, oxygen-poor water than competitors, and thus can feast on plankton without competition. Jellyfish may also benefit from saltier waters, as saltier waters contain more iodine, which is necessary for polyps to turn into jellyfish. Rising sea temperatures caused by climate change may also contribute to jellyfish blooms, because many species of jellyfish are able to survive in warmer waters.[93] Increased nutrients from agricultural or urban runoff with nutrients including nitrogen and phosphorus compounds increase the growth of phytoplankton, causing eutrophication and algal blooms. When the phytoplankton die, they may create dead zones, so-called because they are hypoxic (low in oxygen). This in turn kills fish and other animals, but not jellyfish,[94] allowing them to bloom.[95][96] Jellyfish populations may be expanding globally as a result of land runoff and overfishing of their natural predators.[97][98] Jellyfish are well placed to benefit from disturbance of marine ecosystems. They reproduce rapidly; they prey upon many species, while few species prey on them; and they feed via touch rather than visually, so they can feed effectively at night and in turbid waters.[99][100] It may be difficult for fish stocks to re-establish themselves in marine ecosystems once they have become dominated by jellyfish, because jellyfish feed on plankton, which includes fish eggs and larvae.[101][102][96]


Moon jellyfishes can live in northern hemisphere seas,[103][104] such as the Baltic Sea.[105][106]
As suspected at the turn of this century, [107][108] jellyfish blooms are increasing in frequency. Between 2013 and 2020 the Mediterranean Science Commission monitored on a weekly basis the frequency of such outbreaks in coastal waters from Morocco to the Black Sea, revealing a relatively high frequency of these blooms nearly all year round, with peaks observed from March to July and often again in the autumn. The blooms are caused by different jellyfish species, depending on their localisation within the Basin: one observes a clear dominance of Pelagia noctiluca and Velella velella outbreaks in the western Mediterranean, of Rhizostoma pulmo and Rhopilema nomadica outbreaks in the eastern Mediterranean, and of Aurelia aurita and Mnemiopsis leidyi outbreaks in the Black Sea.[109]

Some jellyfish populations that have shown clear increases in the past few decades are invasive species, newly arrived from other habitats: examples include the Black Sea, Caspian Sea, Baltic Sea, central and eastern Mediterranean, Hawaii, and tropical and subtropical parts of the West Atlantic (including the Caribbean, Gulf of Mexico and Brazil).[105][106]

Jellyfish blooms can have significant impact on community structure. Some carnivorous jellyfish species prey on zooplankton while others graze on primary producers.[110] Reductions in zooplankton and ichthyoplankton due to a jellyfish bloom can ripple through the trophic levels. High-density jellyfish populations can outcompete other predators and reduce fish recruitment.[111] Increased grazing on primary producers by jellyfish can also interrupt energy transfer to higher trophic levels.[112]

During blooms, jellyfish significantly alter the nutrient availability in their environment. Blooms require large amounts of available organic nutrients in the water column to grow, limiting availability for other organisms.[113] Some jellyfish have a symbiotic relationship with single-celled dinoflagellates, allowing them to assimilate inorganic carbon, phosphorus, and nitrogen creating competition for phytoplankton.[113] Their large biomass makes them an important source of dissolved and particulate organic matter for microbial communities through excretion, mucus production, and decomposition.[90][114] The microbes break down the organic matter into inorganic ammonium and phosphate. However, the low carbon availability shifts the process from production to respiration creating low oxygen areas making the dissolved inorganic nitrogen and phosphorus largely unavailable for primary production.

These blooms have very real impacts on industries. Jellyfish can outcompete fish by utilizing open niches in over-fished fisheries.[115] Catch of jellyfish can strain fishing gear and lead to expenses relating to damaged gear. Power plants have been shut down due to jellyfish blocking the flow of cooling water.[116] Blooms have also been harmful for tourism, causing a rise in stings and sometimes the closure of beaches.[117]

Jellyfish form a component of jelly-falls, events where gelatinous zooplankton fall to the seafloor, providing food for the benthic organisms there.[118] In temperate and subpolar regions, jelly-falls usually follow immediately after a bloom.[119]

Habitats

A common Scyphozoan jellyfish seen near beaches in the Florida Panhandle
Most jellyfish are marine animals, although a few hydromedusae inhabit freshwater. The best known freshwater example is the cosmopolitan hydrozoan jellyfish, Craspedacusta sowerbii. It is less than an inch (2.5 cm) in diameter, colorless and does not sting.[120] Some jellyfish populations have become restricted to coastal saltwater lakes, such as Jellyfish Lake in Palau.[121] Jellyfish Lake is a marine lake where millions of golden jellyfish (Mastigias spp.) migrate horizontally across the lake daily.[82]

Although most jellyfish live well off the ocean floor and form part of the plankton, a few species are closely associated with the bottom for much of their lives and can be considered benthic. The upside-down jellyfish in the genus Cassiopea typically lie on the bottom of shallow lagoons where they sometimes pulsate gently with their umbrella top facing down. Even some deep-sea species of hydromedusae and scyphomedusae are usually collected on or near the bottom. All of the stauromedusae are found attached to either seaweed or rocky or other firm material on the bottom.[122]

Some species explicitly adapt to tidal flux. In Roscoe Bay, jellyfish ride the current at ebb tide until they hit a gravel bar, and then descend below the current. They remain in still waters until the tide rises, ascending and allowing it to sweep them back into the bay. They also actively avoid fresh water from mountain snowmelt, diving until they find enough salt.


Parasites
Jellyfish are hosts to a wide variety of parasitic organisms. They act as intermediate hosts of endoparasitic helminths, with the infection being transferred to the definitive host fish after predation. Some digenean trematodes, especially species in the family Lepocreadiidae, use jellyfish as their second intermediate hosts. Fish become infected by the trematodes when they feed on infected jellyfish.

Relation to humans
Jellyfish have long been eaten in some parts of the world. Fisheries have begun harvesting the American cannonball jellyfish, Stomolophus meleagris, along the southern Atlantic coast of the United States and in the Gulf of Mexico for export to Asia.

Jellyfish are also harvested for their collagen, which is being investigated for use in a variety of applications including the treatment of rheumatoid arthritis.

Aquaculture and fisheries of other species often suffer severe losses – and so losses of productivity – due to jellyfish.

Products
Main article: Jellyfish as food
In some countries, including China, Japan, and Korea, jellyfish are a delicacy. The jellyfish is dried to prevent spoiling. Only some 12 species of scyphozoan jellyfish belonging to the order Rhizostomeae are harvested for food, mostly in southeast Asia. Rhizostomes, especially Rhopilema esculentum in China (海蜇 hǎizhé, 'sea stingers') and Stomolophus meleagris (cannonball jellyfish) in the United States, are favored because of their larger and more rigid bodies and because their toxins are harmless to humans.

Traditional processing methods, carried out by a jellyfish master, involve a 20- to 40-day multi-phase procedure in which, after removing the gonads and mucous membranes, the umbrella and oral arms are treated with a mixture of table salt and alum, and compressed. Processing makes the jellyfish drier and more acidic, producing a crisp texture. Jellyfish prepared this way retain 7–10% of their original weight, and the processed product consists of approximately 94% water and 6% protein. Freshly processed jellyfish has a white, creamy color and turns yellow or brown during prolonged storage.

In China, processed jellyfish are desalted by soaking in water overnight and eaten cooked or raw. The dish is often served shredded with a dressing of oil, soy sauce, vinegar and sugar, or as a salad with vegetables. In Japan, cured jellyfish are rinsed, cut into strips and served with vinegar as an appetizer. Desalted, ready-to-eat products are also available.

Biotechnology
The hydromedusa Aequorea victoria was the source of green fluorescent protein, studied for its role in bioluminescence and later for use as a marker in genetic engineering.
Pliny the Elder reported in his Natural History that the slime of the jellyfish "Pulmo marinus" produced light when rubbed on a walking stick.

In 1961, Osamu Shimomura extracted green fluorescent protein (GFP) and another bioluminescent protein, called aequorin, from the large and abundant hydromedusa Aequorea victoria, while studying photoproteins that cause bioluminescence in this species. Three decades later, Douglas Prasher sequenced and cloned the gene for GFP. Martin Chalfie figured out how to use GFP as a fluorescent marker of genes inserted into other cells or organisms. Roger Tsien later chemically manipulated GFP to produce other fluorescent colors to use as markers. In 2008, Shimomura, Chalfie and Tsien won the Nobel Prize in Chemistry for their work with GFP. Man-made GFP became widely used as a fluorescent tag to show which cells or tissues express specific genes. The genetic engineering technique fuses the gene of interest to the GFP gene. The fused DNA is then put into a cell, to generate either a cell line or (via IVF techniques) an entire animal bearing the gene. In the cell or animal, the artificial gene turns on in the same tissues and the same time as the normal gene, making a fusion of the normal protein with GFP attached to the end, illuminating the animal or cell reveals what tissues express that protein—or at what stage of development. The fluorescence shows where the gene is expressed.

Aquarium display
Jellyfish are displayed in many public aquariums. Often the tank's background is blue and the animals are illuminated by side light, increasing the contrast between the animal and the background. In natural conditions, many jellies are so transparent that they are nearly invisible. Jellyfish are not adapted to closed spaces. They depend on currents to transport them from place to place. Professional exhibits as in the Monterey Bay Aquarium feature precise water flows, typically in circular tanks to avoid trapping specimens in corners. The outflow is spread out over a large surface area and the inflow enters as a sheet of water in front of the outflow, so the jellyfish do not get sucked into it. As of 2009, jellyfish were becoming popular in home aquariums, where they require similar equipment.

Stings
Jellyfish are armed with nematocysts, a type of specialized stinging cell. Contact with a jellyfish tentacle can trigger millions of nematocysts to pierce the skin and inject venom, but only some species' venom causes an adverse reaction in humans. In a study published in Communications Biology, researchers found a jellyfish species called Cassiopea xamachana which when triggered will release tiny balls of cells that swim around the jellyfish stinging everything in their path. Researchers described these as "self-propelling microscopic grenades" and named them cassiosomes.

The effects of stings range from mild discomfort to extreme pain and death. Most jellyfish stings are not deadly, but stings of some box jellyfish (Irukandji jellyfish), such as the sea wasp, can be deadly. Stings may cause anaphylaxis (a form of shock), which can be fatal. Jellyfish kill 20 to 40 people a year in the Philippines alone. In 2006 the Spanish Red Cross treated 19,000 stung swimmers along the Costa Brava.

Vinegar (3–10% aqueous acetic acid) may help with box jellyfish stings but not the stings of the Portuguese man o' war. Clearing the area of jelly and tentacles reduces nematocyst firing. Scraping the affected skin, such as with the edge of a credit card, may remove remaining nematocysts. Once the skin has been cleaned of nematocysts, hydrocortisone cream applied locally reduces pain and inflammation. Antihistamines may help to control itching. Immunobased antivenins are used for serious box jellyfish stings.

In Elba Island and Corsica dittrichia viscosa is now used by residents and tourists to heal stings from jellyfish, bees and wasps pressing fresh leaves on the skin with quick results.

Mechanical issues
Jellyfish in large quantities can fill and split fishing nets and crush captured fish. They can clog cooling equipment, having disabled power stations in several countries; jellyfish caused a cascading blackout in the Philippines in 1999, as well as damaging the Diablo Canyon Power Plant in California in 2008. They can also stop desalination plants and ships' engines.

Jellyfish - Sea Jellies - Medusa (Subphylum Medusozoa) by millicand@rocketmail.com

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Jellyfish - Sea Jellies - Medusa (Subphylum Medusozoa)

Jellyfish, also known sea jellies, are the medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria.

Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles, although a few are anchored to the seabed by stalks rather than being mobile. The bell can pulsate to provide propulsion for highly efficient locomotion. The tentacles are armed with stinging cells and may be used to capture prey and defend against predators. Jellyfish have a complex life cycle. The medusa is normally the sexual phase, which produces planula larvae; these then disperse widely and enter a sedentary polyp phase, before reaching sexual maturity.

Jellyfish are found all over the world, from surface waters to the deep sea. Scyphozoans (the "true jellyfish") are exclusively marine, but some hydrozoans with a similar appearance live in freshwater. Large, often colorful, jellyfish are common in coastal zones worldwide. The medusae of most species are fast-growing, and mature within a few months then die soon after breeding, but the polyp stage, attached to the seabed, may be much more long-lived. Jellyfish have been in existence for at least 500 million years, and possibly 700 million years or more, making them the oldest multi-organ animal group.

Jellyfish are eaten by humans in certain cultures. They are considered a delicacy in some Asian countries, where species in the Rhizostomeae order are pressed and salted to remove excess water. Australian researchers have described them as a "perfect food": sustainable and protein-rich but relatively low in food energy.

They are also used in research, where the green fluorescent protein used by some species to cause bioluminescence has been adapted as a fluorescent marker for genes inserted into other cells or organisms.

The stinging cells used by jellyfish to subdue their prey can injure humans. Thousands of swimmers worldwide are stung every year, with effects ranging from mild discomfort to serious injury or even death. When conditions are favourable, jellyfish can form vast swarms, which can be responsible for damage to fishing gear by filling fishing nets, and sometimes clog the cooling systems of power and desalination plants which draw their water from the sea.


Names
The name jellyfish, in use since 1796, has traditionally been applied to medusae and all similar animals including the comb jellies (ctenophores, another phylum). The term jellies or sea jellies is more recent, having been introduced by public aquaria in an effort to avoid use of the word "fish" with its modern connotation of an animal with a backbone, though shellfish, cuttlefish and starfish are not vertebrates either. In scientific literature, "jelly" and "jellyfish" have been used interchangeably. Many sources refer to only scyphozoans as "true jellyfish".

A group of jellyfish is called a "smack" or a "smuck".

Definition
The term jellyfish broadly corresponds to medusae, that is, a life-cycle stage in the Medusozoa. The American evolutionary biologist Paulyn Cartwright gives the following general definition:

Typically, medusozoan cnidarians have a pelagic, predatory jellyfish stage in their life cycle; staurozoans are the exceptions [as they are stalked].

The Merriam-Webster dictionary defines jellyfish as follows:

A free-swimming marine coelenterate that is the sexually reproducing form of a hydrozoan or scyphozoan and has a nearly transparent saucer-shaped body and extensible marginal tentacles studded with stinging cells.

Given that jellyfish is a common name, its mapping to biological groups is inexact. Some authorities have called the comb jellies and certain salps jellyfish, though other authorities state that neither of these are jellyfish, which they consider should be limited to certain groups within the medusozoa.

The non-medusozoan clades called jellyfish by some but not all authorities (both agreeing and disagreeing citations are given in each case) are indicated with on the following cladogram of the animal kingdom:

Jellyfish are not a clade, as they include most of the Medusozoa, barring some of the Hydrozoa. The medusozoan groups included by authorities are indicated on the following phylogenetic tree by the presence of citations. Names of included jellyfish, in English where possible, are shown in boldface; the presence of a named and cited example indicates that at least that species within its group has been called a jellyfish.

Taxonomy
The subphylum Medusozoa includes all cnidarians with a medusa stage in their life cycle. The basic cycle is egg, planula larva, polyp, medusa, with the medusa being the sexual stage. The polyp stage is sometimes secondarily lost. The subphylum include the major taxa, Scyphozoa (large jellyfish), Cubozoa (box jellyfish) and Hydrozoa (small jellyfish), and excludes Anthozoa (corals and sea anemones). This suggests that the medusa form evolved after the polyps. Medusozoans have tetramerous symmetry, with parts in fours or multiples of four.

The four major classes of medusozoan Cnidaria are:
Scyphozoa are sometimes called true jellyfish, though they are no more truly jellyfish than the others listed here. They have tetra-radial symmetry. Most have tentacles around the outer margin of the bowl-shaped bell, and long, oral arms around the mouth in the center of the subumbrella.
Cubozoa (box jellyfish) have a (rounded) box-shaped bell, and their velarium assists them to swim more quickly. Box jellyfish may be related more closely to scyphozoan jellyfish than either are to the Hydrozoa.
Hydrozoa medusae also have tetra-radial symmetry, nearly always have a velum (diaphragm used in swimming) attached just inside the bell margin, do not have oral arms, but a much smaller central stalk-like structure, the manubrium, with terminal mouth opening, and are distinguished by the absence of cells in the mesoglea. Hydrozoa show great diversity of lifestyle; some species maintain the polyp form for their entire life and do not form medusae at all (such as Hydra, which is hence not considered a jellyfish), and a few are entirely medusal and have no polyp form.
Staurozoa (stalked jellyfish) are characterized by a medusa form that is generally sessile, oriented upside down and with a stalk emerging from the apex of the "calyx" (bell), which attaches to the substrate. At least some Staurozoa also have a polyp form that alternates with the medusoid portion of the life cycle. Until recently, Staurozoa were classified within the Scyphozoa.
There are over 200 species of Scyphozoa, about 50 species of Staurozoa, about 50 species of Cubozoa, and the Hydrozoa includes about 1000–1500 species that produce medusae, but many more species that do not.

Fossil history
Since jellyfish have no hard parts, fossils are rare. The oldest unambiguous fossil of a free-swimming medusa is Burgessomedusa from the mid Cambrian Burgess Shale of Canada, which is likely either a stem group of box jellyfish (Cubozoa) or Acraspeda (the clade including Staurozoa, Cubozoa, and Scyphozoa). Other claimed records from the Cambrian of China and Utah in the United States are uncertain, and possibly represent ctenophores instead.

Anatomy
The main feature of a true jellyfish is the umbrella-shaped bell. This is a hollow structure consisting of a mass of transparent jelly-like matter known as mesoglea, which forms the hydrostatic skeleton of the animal. 95% or more of the mesogloea consists of water, but it also contains collagen and other fibrous proteins, as well as wandering amoebocytes which can engulf debris and bacteria. The mesogloea is bordered by the epidermis on the outside and the gastrodermis on the inside. The edge of the bell is often divided into rounded lobes known as lappets, which allow the bell to flex. In the gaps or niches between the lappets are dangling rudimentary sense organs known as rhopalia, and the margin of the bell often bears tentacles.


Anatomy of a scyphozoan jellyfish
On the underside of the bell is the manubrium, a stalk-like structure hanging down from the centre, with the mouth, which also functions as the anus, at its tip. There are often four oral arms connected to the manubrium, streaming away into the water below. The mouth opens into the gastrovascular cavity, where digestion takes place and nutrients are absorbed. This is subdivided by four thick septa into a central stomach and four gastric pockets. The four pairs of gonads are attached to the septa, and close to them four septal funnels open to the exterior, perhaps supplying good oxygenation to the gonads. Near the free edges of the septa, gastric filaments extend into the gastric cavity; these are armed with nematocysts and enzyme-producing cells and play a role in subduing and digesting the prey. In some scyphozoans, the gastric cavity is joined to radial canals which branch extensively and may join a marginal ring canal. Cilia in these canals circulate the fluid in a regular direction.


Discharge mechanism of a nematocyst
The box jellyfish is largely similar in structure. It has a squarish, box-like bell. A short pedalium or stalk hangs from each of the four lower corners. One or more long, slender tentacles are attached to each pedalium. The rim of the bell is folded inwards to form a shelf known as a velarium which restricts the bell's aperture and creates a powerful jet when the bell pulsates, allowing box jellyfish to swim faster than true jellyfish. Hydrozoans are also similar, usually with just four tentacles at the edge of the bell, although many hydrozoans are colonial and may not have a free-living medusal stage. In some species, a non-detachable bud known as a gonophore is formed that contains a gonad but is missing many other medusal features such as tentacles and rhopalia. Stalked jellyfish are attached to a solid surface by a basal disk, and resemble a polyp, the oral end of which has partially developed into a medusa with tentacle-bearing lobes and a central manubrium with four-sided mouth.

Most jellyfish do not have specialized systems for osmoregulation, respiration and circulation, and do not have a central nervous system. Nematocysts, which deliver the sting, are located mostly on the tentacles; true jellyfish also have them around the mouth and stomach. Jellyfish do not need a respiratory system because sufficient oxygen diffuses through the epidermis. They have limited control over their movement, but can navigate with the pulsations of the bell-like body; some species are active swimmers most of the time, while others largely drift. The rhopalia contain rudimentary sense organs which are able to detect light, water-borne vibrations, odour and orientation. A loose network of nerves called a "nerve net" is located in the epidermis. Although traditionally thought not to have a central nervous system, nerve net concentration and ganglion-like structures could be considered to constitute one in most species. A jellyfish detects stimuli, and transmits impulses both throughout the nerve net and around a circular nerve ring, to other nerve cells. The rhopalial ganglia contain pacemaker neurones which control swimming rate and direction.

In many species of jellyfish, the rhopalia include ocelli, light-sensitive organs able to tell light from dark. These are generally pigment spot ocelli, which have some of their cells pigmented. The rhopalia are suspended on stalks with heavy crystals at one end, acting like gyroscopes to orient the eyes skyward. Certain jellyfish look upward at the mangrove canopy while making a daily migration from mangrove swamps into the open lagoon, where they feed, and back again.

Box jellyfish have more advanced vision than the other groups. Each individual has 24 eyes, two of which are capable of seeing colour, and four parallel information processing areas that act in competition, supposedly making them one of the few kinds of animal to have a 360-degree view of its environment.

Box jellyfish eye
The study of jellyfish eye evolution is an intermediary to a better understanding of how visual systems evolved on Earth. Jellyfish exhibit immense variation in visual systems ranging from photoreceptive cell patches seen in simple photoreceptive systems to more derived complex eyes seen in box jellyfish. Major topics of jellyfish visual system research (with an emphasis on box jellyfish) include: the evolution of jellyfish vision from simple to complex visual systems), the eye morphology and molecular structures of box jellyfish (including comparisons to vertebrate eyes), and various uses of vision including task-guided behaviors and niche specialization.

Evolution
Experimental evidence for photosensitivity and photoreception in cnidarians antecedes the mid 1900s, and a rich body of research has since covered evolution of visual systems in jellyfish. Jellyfish visual systems range from simple photoreceptive cells to complex image-forming eyes. More ancestral visual systems incorporate extraocular vision (vision without eyes) that encompass numerous receptors dedicated to single-function behaviors. More derived visual systems comprise perception that is capable of multiple task-guided behaviors.

Although they lack a true brain, cnidarian jellyfish have a "ring" nervous system that plays a significant role in motor and sensory activity. This net of nerves is responsible for muscle contraction and movement and culminates the emergence of photosensitive structures. Across Cnidaria, there is large variation in the systems that underlie photosensitivity. Photosensitive structures range from non-specialized groups of cells, to more "conventional" eyes similar to those of vertebrates. The general evolutionary steps to develop complex vision include (from more ancestral to more derived states): non-directional photoreception, directional photoreception, low-resolution vision, and high-resolution vision. Increased habitat and task complexity has favored the high-resolution visual systems common in derived cnidarians such as box jellyfish.

Basal visual systems observed in various cnidarians exhibit photosensitivity representative of a single task or behavior. Extraocular photoreception (a form of non-directional photoreception), is the most basic form of light sensitivity and guides a variety of behaviors among cnidarians. It can function to regulate circadian rhythm (as seen in eyeless hydrozoans) and other light-guided behaviors responsive to the intensity and spectrum of light. Extraocular photoreception can function additionally in positive phototaxis (in planula larvae of hydrozoans), as well as in avoiding harmful amounts of UV radiation via negative phototaxis. Directional photoreception (the ability to perceive direction of incoming light) allows for more complex phototactic responses to light, and likely evolved by means of membrane stacking. The resulting behavioral responses can range from guided spawning events timed by moonlight to shadow responses for potential predator avoidance. Light-guided behaviors are observed in numerous scyphozoans including the common moon jelly, Aurelia aurita, which migrates in response to changes in ambient light and solar position even though they lack proper eyes.

The low-resolution visual system of box jellyfish is more derived than directional photoreception, and thus box jellyfish vision represents the most basic form of true vision in which multiple directional photoreceptors combine to create the first imaging and spatial resolution. This is different from the high-resolution vision that is observed in camera or compound eyes of vertebrates and cephalopods that rely on focusing optics. Critically, the visual systems of box jellyfish are responsible for guiding multiple tasks or behaviors in contrast to less derived visual systems in other jellyfish that guide single behavioral functions. These behaviors include phototaxis based on sunlight (positive) or shadows (negative), obstacle avoidance, and control of swim-pulse rate.

Box jellyfish possess "proper eyes" (similar to vertebrates) that allow them to inhabit environments that lesser derived medusae cannot. In fact, they are considered the only class in the clade Medusozoa that have behaviors necessitating spatial resolution and genuine vision. However, the lens in their eyes are more functionally similar to cup-eyes exhibited in low-resolution organisms, and have very little to no focusing capability. The lack of the ability to focus is due to the focal length exceeding the distance to the retina, thus generating unfocused images and limiting spatial resolution. The visual system is still sufficient for box jellyfish to produce an image to help with tasks such as object avoidance.

Utility as a model organism
Box jellyfish eyes are a visual system that is sophisticated in numerous ways. These intricacies include the considerable variation within the morphology of box jellyfishes' eyes (including their task/behavior specification), and the molecular makeup of their eyes including: photoreceptors, opsins, lenses, and synapses. The comparison of these attributes to more derived visual systems can allow for a further understanding of how the evolution of more derived visual systems may have occurred, and puts into perspective how box jellyfish can play the role as an evolutionary/developmental model for all visual systems.

Characteristics
Box jellyfish visual systems are both diverse and complex, comprising multiple photosystems. There is likely considerable variation in visual properties between species of box jellyfish given the significant inter-species morphological and physiological variation. Eyes tend to differ in size and shape, along with number of receptors (including opsins), and physiology across species of box jellyfish.

Box jellyfish have a series of intricate lensed eyes that are similar to those of more derived multicellular organisms such as vertebrates. Their 24 eyes fit into four different morphological categories. These categories consist of two large, morphologically different medial eyes (a lower and upper lensed eye) containing spherical lenses, a lateral pair of pigment slit eyes, and a lateral pair of pigment pit eyes. The eyes are situated on rhopalia (small sensory structures) which serve sensory functions of the box jellyfish and arise from the cavities of the exumbrella (the surface of the body) on the side of the bells of the jellyfish. The two large eyes are located on the mid-line of the club and are considered complex because they contain lenses. The four remaining eyes lie laterally on either side of each rhopalia and are considered simple. The simple eyes are observed as small invaginated cups of epithelium that have developed pigmentation. The larger of the complex eyes contains a cellular cornea created by a mono ciliated epithelium, cellular lens, homogenous capsule to the lens, vitreous body with prismatic elements, and a retina of pigmented cells. The smaller of the complex eyes is said to be slightly less complex given that it lacks a capsule but otherwise contains the same structure as the larger eye.

Box jellyfish have multiple photosystems that comprise different sets of eyes. Evidence includes immunocytochemical and molecular data that show photopigment differences among the different morphological eye types, and physiological experiments done on box jellyfish to suggest behavioral differences among photosystems. Each individual eye type constitutes photosystems that work collectively to control visually guided behaviors.

Box jellyfish eyes primarily use c-PRCs (ciliary photoreceptor cells) similar to that of vertebrate eyes. These cells undergo phototransduction cascades (process of light absorption by photoreceptors) that are triggered by c-opsins. Available opsin sequences suggest that there are two types of opsins possessed by all cnidarians including an ancient phylogenetic opsin, and a sister ciliary opsin to the c-opsins group. Box jellyfish could have both ciliary and cnidops (cnidarian opsins), which is something not previously believed to appear in the same retina. Nevertheless, it is not entirely evident whether cnidarians possess multiple opsins that are capable of having distinctive spectral sensitivities.

Comparison with other organisms
Comparative research on genetic and molecular makeup of box jellyfishes' eyes versus more derived eyes seen in vertebrates and cephalopods focuses on: lenses and crystallin composition, synapses, and Pax genes and their implied evidence for shared primordial (ancestral) genes in eye evolution.

Box jellyfish eyes are said to be an evolutionary/developmental model of all eyes based on their evolutionary recruitment of crystallins and Pax genes. Research done on box jellyfish including Tripedalia cystophora has suggested that they possess a single Pax gene, PaxB. PaxB functions by binding to crystallin promoters and activating them. PaxB in situ hybridization resulted in PaxB expression in the lens, retina, and statocysts. These results and the rejection of the prior hypothesis that Pax6 was an ancestral Pax gene in eyes has led to the conclusion that PaxB was a primordial gene in eye evolution, and that the eyes of all organisms likely share a common ancestor.

The lens structure of box jellyfish appears very similar to those of other organisms, but the crystallins are distinct in both function and appearance. Weak reactions were seen within the sera and there were very weak sequence similarities within the crystallins among vertebrate and invertebrate lenses. This is likely due to differences in lower molecular weight proteins and the subsequent lack of immunological reactions with antisera that other organisms' lenses exhibit.

All four of the visual systems of box jellyfish species investigated with detail (Carybdea marsupialis, Chiropsalmus quadrumanus, Tamoya haplonema and Tripedalia cystophora) have invaginated synapses, but only in the upper and lower lensed eyes. Different densities were found between the upper and lower lenses, and between species. Four types of chemical synapses have been discovered within the rhopalia which could help in understanding neural organization including: clear unidirectional, dense-core unidirectional, clear bidirectional, and clear and dense-core bidirectional. The synapses of the lensed eyes could be useful as markers to learn more about the neural circuit in box jellyfish retinal areas.

Evolution as a response to natural stimuli
The primary adaptive responses to environmental variation observed in box jellyfish eyes include pupillary constriction speeds in response to light environments, as well as photoreceptor tuning and lens adaptations to better respond to shifts between light environments and darkness. Interestingly, some box jellyfish species' eyes appear to have evolved more focused vision in response to their habitat.

Pupillary contraction appears to have evolved in response to variation in the light environment across ecological niches across three species of box jellyfish (Chironex fleckeri, Chiropsella bronzie, and Carukia barnesi). Behavioral studies suggest that faster pupil contraction rates allow for greater object avoidance, and in fact, species with more complex habitats exhibit faster rates. Ch. bronzie inhabit shallow beach fronts that have low visibility and very few obstacles, thus, faster pupil contraction in response to objects in their environment is not important. Ca. barnesi and Ch. fleckeri are found in more three-dimensionally complex environments like mangroves with an abundance of natural obstacles, where faster pupil contraction is more adaptive. Behavioral studies support the idea that faster pupillary contraction rates assist with obstacle avoidance as well as depth adjustments in response to differing light intensities.

Light/dark adaptation via pupillary light reflexes is an additional form of an evolutionary response to the light environment. This relates to the pupil's response to shifts between light intensity (generally from sunlight to darkness). In the process of light/dark adaptation, the upper and lower lens eyes of different box jellyfish species vary in specific function. The lower lens-eyes contain pigmented photoreceptors and long pigment cells with dark pigments that migrate on light/dark adaptation, while the upper-lens eyes play a concentrated role in light direction and phototaxis given that they face upward towards the water surface (towards the sun or moon). The upper lens of Ch. bronzie does not exhibit any considerable optical power while Tr. cystophora (a box jellyfish species that tends to live in mangroves) does. The ability to use light to visually guide behavior is not of as much importance to Ch. bronzie as it is to species in more obstacle-filled environments. Differences in visually guided behavior serve as evidence that species that share the same number and structure of eyes can exhibit differences in how they control behavior.

Largest and smallest
Jellyfish range from about one millimeter in bell height and diameter, to nearly 2 metres (6+1⁄2 ft) in bell height and diameter; the tentacles and mouth parts usually extend beyond this bell dimension.

The smallest jellyfish are the peculiar creeping jellyfish in the genera Staurocladia and Eleutheria, which have bell disks from 0.5 millimetres (1⁄32 in) to a few millimeters in diameter, with short tentacles that extend out beyond this, which these jellyfish use to move across the surface of seaweed or the bottoms of rocky pools; many of these tiny creeping jellyfish cannot be seen in the field without a hand lens or microscope. They can reproduce asexually by fission (splitting in half). Other very small jellyfish, which have bells about one millimeter, are the hydromedusae of many species that have just been released from their parent polyps; some of these live only a few minutes before shedding their gametes in the plankton and then dying, while others will grow in the plankton for weeks or months. The hydromedusae Cladonema radiatum and Cladonema californicum are also very small, living for months, yet never growing beyond a few mm in bell height and diameter.

The lion's mane jellyfish, Cyanea capillata, was long-cited as the largest jellyfish, and arguably the longest animal in the world, with fine, thread-like tentacles that may extend up to 36.5 m (119 ft 9 in) long (though most are nowhere near that large). They have a moderately painful, but rarely fatal, sting. The increasingly common giant Nomura's jellyfish, Nemopilema nomurai, found in some, but not all years in the waters of Japan, Korea and China in summer and autumn is another candidate for "largest jellyfish", in terms of diameter and weight, since the largest Nomura's jellyfish in late autumn can reach 2 m (6 ft 7 in) in bell (body) diameter and about 200 kg (440 lb) in weight, with average specimens frequently reaching 0.9 m (2 ft 11 in) in bell diameter and about 150 kg (330 lb) in weight. The large bell mass of the giant Nomura's jellyfish can dwarf a diver and is nearly always much greater than the Lion's Mane, whose bell diameter can reach 1 m (3 ft 3 in).

The rarely encountered deep-sea jellyfish Stygiomedusa gigantea is another candidate for "largest jellyfish", with its thick, massive bell up to 100 cm (3 ft 3 in) wide, and four thick, "strap-like" oral arms extending up to 6 m (19+1⁄2 ft) in length, very different from the typical fine, threadlike tentacles that rim the umbrella of more-typical-looking jellyfish, including the Lion's Mane.

Desmonema glaciale, which lives in the Antarctic region, can reach a very large size (several meters). Purple-striped jelly (Chrysaora colorata) can also be extremely long (up to 15 feet).

Life history and behavior
Life cycle
Jellyfish have a complex life cycle which includes both sexual and asexual phases, with the medusa being the sexual stage in most instances. Sperm fertilize eggs, which develop into larval planulae, become polyps, bud into ephyrae and then transform into adult medusae. In some species certain stages may be skipped.

Upon reaching adult size, jellyfish spawn regularly if there is a sufficient supply of food. In most species, spawning is controlled by light, with all individuals spawning at about the same time of day; in many instances this is at dawn or dusk. Jellyfish are usually either male or female (with occasional hermaphrodites). In most cases, adults release sperm and eggs into the surrounding water, where the unprotected eggs are fertilized and develop into larvae. In a few species, the sperm swim into the female's mouth, fertilizing the eggs within her body, where they remain during early development stages. In moon jellies, the eggs lodge in pits on the oral arms, which form a temporary brood chamber for the developing planula larvae.

The planula is a small larva covered with cilia. When sufficiently developed, it settles onto a firm surface and develops into a polyp. The polyp generally consists of a small stalk topped by a mouth that is ringed by upward-facing tentacles. The polyps resemble those of closely related anthozoans, such as sea anemones and corals. The jellyfish polyp may be sessile, living on the bottom, boat hulls or other substrates, or it may be free-floating or attached to tiny bits of free-living plankton or rarely, fish or other invertebrates. Polyps may be solitary or colonial. Most polyps are only millimetres in diameter and feed continuously. The polyp stage may last for years.

After an interval and stimulated by seasonal or hormonal changes, the polyp may begin reproducing asexually by budding and, in the Scyphozoa, is called a segmenting polyp, or a scyphistoma. Budding produces more scyphistomae and also ephyrae. Budding sites vary by species; from the tentacle bulbs, the manubrium (above the mouth), or the gonads of hydromedusae. In a process known as strobilation, the polyp's tentacles are reabsorbed and the body starts to narrow, forming transverse constrictions, in several places near the upper extremity of the polyp. These deepen as the constriction sites migrate down the body, and separate segments known as ephyra detach. These are free-swimming precursors of the adult medusa stage, which is the life stage that is typically identified as a jellyfish. The ephyrae, usually only a millimeter or two across initially, swim away from the polyp and grow. Limnomedusae polyps can asexually produce a creeping frustule larval form, which crawls away before developing into another polyp. A few species can produce new medusae by budding directly from the medusan stage. Some hydromedusae reproduce by fission.

Lifespan
Little is known of the life histories of many jellyfish as the places on the seabed where the benthic forms of those species live have not been found. However, an asexually reproducing strobila form can sometimes live for several years, producing new medusae (ephyra larvae) each year.

An unusual species, Turritopsis dohrnii, formerly classified as Turritopsis nutricula, might be effectively immortal because of its ability under certain circumstances to transform from medusa back to the polyp stage, thereby escaping the death that typically awaits medusae post-reproduction if they have not otherwise been eaten by some other organism. So far this reversal has been observed only in the laboratory.

Locomotion
Jellyfish locomotion is highly efficient. Muscles in the jellylike bell contract, setting up a start vortex and propelling the animal. When the contraction ends, the bell recoils elastically, creating a stop vortex with no extra energy input.
Using the moon jelly Aurelia aurita as an example, jellyfish have been shown to be the most energy-efficient swimmers of all animals. They move through the water by radially expanding and contracting their bell-shaped bodies to push water behind them. They pause between the contraction and expansion phases to create two vortex rings. Muscles are used for the contraction of the body, which creates the first vortex and pushes the animal forward, but the mesoglea is so elastic that the expansion is powered exclusively by relaxing the bell, which releases the energy stored from the contraction. Meanwhile, the second vortex ring starts to spin faster, sucking water into the bell and pushing against the centre of the body, giving a secondary and "free" boost forward. The mechanism, called passive energy recapture, only works in relatively small jellyfish moving at low speeds, allowing the animal to travel 30 percent farther on each swimming cycle. Jellyfish achieved a 48 percent lower cost of transport (food and oxygen intake versus energy spent in movement) than other animals in similar studies. One reason for this is that most of the gelatinous tissue of the bell is inactive, using no energy during swimming.

Ecology
Diet
Jellyfish are, like other cnidarians, generally carnivorous (or parasitic), feeding on planktonic organisms, crustaceans, small fish, fish eggs and larvae, and other jellyfish, ingesting food and voiding undigested waste through the mouth. They hunt passively using their tentacles as drift lines, or sink through the water with their tentacles spread widely; the tentacles, which contain nematocysts to stun or kill the prey, may then flex to help bring it to the mouth. Their swimming technique also helps them to capture prey; when their bell expands it sucks in water which brings more potential prey within reach of the tentacles.

A few species such as Aglaura hemistoma are omnivorous, feeding on microplankton which is a mixture of zooplankton and phytoplankton (microscopic plants) such as dinoflagellates. Others harbour mutualistic algae (Zooxanthellae) in their tissues; the spotted jellyfish (Mastigias papua) is typical of these, deriving part of its nutrition from the products of photosynthesis, and part from captured zooplankton. The upside-down jellyfish (Cassiopea andromeda) also has a symbiotic relationship with microalgae, but captures tiny animals to supplement their diet. This is done by releasing tiny balls of living cells composed of mesoglea. These use cilia to drive them through water and stinging cells which stun the prey. The blobs also seems to have digestive capabilities.

Predation
Other species of jellyfish are among the most common and important jellyfish predators. Sea anemones may eat jellyfish that drift into their range. Other predators include tunas, sharks, swordfish, sea turtles and penguins. Jellyfish washed up on the beach are consumed by foxes, other terrestrial mammals and birds. In general however, few animals prey on jellyfish; they can broadly be considered to be top predators in the food chain. Once jellyfish have become dominant in an ecosystem, for example through overfishing which removes predators of jellyfish larvae, there may be no obvious way for the previous balance to be restored: they eat fish eggs and juvenile fish, and compete with fish for food, preventing fish stocks from recovering.

Symbiosis
Some small fish are immune to the stings of the jellyfish and live among the tentacles, serving as bait in a fish trap; they are safe from potential predators and are able to share the fish caught by the jellyfish. The cannonball jellyfish has a symbiotic relationship with ten different species of fish, and with the longnose spider crab, which lives inside the bell, sharing the jellyfish's food and nibbling its tissues.

Main article: Jellyfish bloom
Jellyfish form large masses or blooms in certain environmental conditions of ocean currents, nutrients, sunshine, temperature, season, prey availability, reduced predation and oxygen concentration. Currents collect jellyfish together, especially in years with unusually high populations. Jellyfish can detect marine currents and swim against the current to congregate in blooms. Jellyfish are better able to survive in nutrient-rich, oxygen-poor water than competitors, and thus can feast on plankton without competition. Jellyfish may also benefit from saltier waters, as saltier waters contain more iodine, which is necessary for polyps to turn into jellyfish. Rising sea temperatures caused by climate change may also contribute to jellyfish blooms, because many species of jellyfish are able to survive in warmer waters. Increased nutrients from agricultural or urban runoff with nutrients including nitrogen and phosphorus compounds increase the growth of phytoplankton, causing eutrophication and algal blooms. When the phytoplankton die, they may create dead zones, so-called because they are hypoxic (low in oxygen). This in turn kills fish and other animals, but not jellyfish, allowing them to bloom. Jellyfish populations may be expanding globally as a result of land runoff and overfishing of their natural predators. Jellyfish are well placed to benefit from disturbance of marine ecosystems. They reproduce rapidly; they prey upon many species, while few species prey on them; and they feed via touch rather than visually, so they can feed effectively at night and in turbid waters. It may be difficult for fish stocks to re-establish themselves in marine ecosystems once they have become dominated by jellyfish, because jellyfish feed on plankton, which includes fish eggs and larvae.

As suspected at the turn of this century, jellyfish blooms are increasing in frequency. Between 2013 and 2020 the Mediterranean Science Commission monitored on a weekly basis the frequency of such outbreaks in coastal waters from Morocco to the Black Sea, revealing a relatively high frequency of these blooms nearly all year round, with peaks observed from March to July and often again in the autumn. The blooms are caused by different jellyfish species, depending on their localisation within the Basin: one observes a clear dominance of Pelagia noctiluca and Velella velella outbreaks in the western Mediterranean, of Rhizostoma pulmo and Rhopilema nomadica outbreaks in the eastern Mediterranean, and of Aurelia aurita and Mnemiopsis leidyi outbreaks in the Black Sea.

Some jellyfish populations that have shown clear increases in the past few decades are invasive species, newly arrived from other habitats: examples include the Black Sea, Caspian Sea, Baltic Sea, central and eastern Mediterranean, Hawaii, and tropical and subtropical parts of the West Atlantic (including the Caribbean, Gulf of Mexico and Brazil).

Jellyfish blooms can have significant impact on community structure. Some carnivorous jellyfish species prey on zooplankton while others graze on primary producers. Reductions in zooplankton and ichthyoplankton due to a jellyfish bloom can ripple through the trophic levels. High-density jellyfish populations can outcompete other predators and reduce fish recruitment. Increased grazing on primary producers by jellyfish can also interrupt energy transfer to higher trophic levels.

During blooms, jellyfish significantly alter the nutrient availability in their environment. Blooms require large amounts of available organic nutrients in the water column to grow, limiting availability for other organisms. Some jellyfish have a symbiotic relationship with single-celled dinoflagellates, allowing them to assimilate inorganic carbon, phosphorus, and nitrogen creating competition for phytoplankton. Their large biomass makes them an important source of dissolved and particulate organic matter for microbial communities through excretion, mucus production, and decomposition. The microbes break down the organic matter into inorganic ammonium and phosphate. However, the low carbon availability shifts the process from production to respiration creating low oxygen areas making the dissolved inorganic nitrogen and phosphorus largely unavailable for primary production.

These blooms have very real impacts on industries. Jellyfish can outcompete fish by utilizing open niches in over-fished fisheries. Catch of jellyfish can strain fishing gear and lead to expenses relating to damaged gear. Power plants have been shut down due to jellyfish blocking the flow of cooling water. Blooms have also been harmful for tourism, causing a rise in stings and sometimes the closure of beaches.

Jellyfish form a component of jelly-falls, events where gelatinous zooplankton fall to the seafloor, providing food for the benthic organisms there. In temperate and subpolar regions, jelly-falls usually follow immediately after a bloom.

Habitats
Most jellyfish are marine animals, although a few hydromedusae inhabit freshwater. The best known freshwater example is the cosmopolitan hydrozoan jellyfish, Craspedacusta sowerbii. It is less than an inch (2.5 cm) in diameter, colorless and does not sting. Some jellyfish populations have become restricted to coastal saltwater lakes, such as Jellyfish Lake in Palau. Jellyfish Lake is a marine lake where millions of golden jellyfish (Mastigias spp.) migrate horizontally across the lake daily.

Although most jellyfish live well off the ocean floor and form part of the plankton, a few species are closely associated with the bottom for much of their lives and can be considered benthic. The upside-down jellyfish in the genus Cassiopea typically lie on the bottom of shallow lagoons where they sometimes pulsate gently with their umbrella top facing down. Even some deep-sea species of hydromedusae and scyphomedusae are usually collected on or near the bottom. All of the stauromedusae are found attached to either seaweed or rocky or other firm material on the bottom.

Some species explicitly adapt to tidal flux. In Roscoe Bay, jellyfish ride the current at ebb tide until they hit a gravel bar, and then descend below the current. They remain in still waters until the tide rises, ascending and allowing it to sweep them back into the bay. They also actively avoid fresh water from mountain snowmelt, diving until they find enough salt.


Parasites
Jellyfish are hosts to a wide variety of parasitic organisms. They act as intermediate hosts of endoparasitic helminths, with the infection being transferred to the definitive host fish after predation. Some digenean trematodes, especially species in the family Lepocreadiidae, use jellyfish as their second intermediate hosts. Fish become infected by the trematodes when they feed on infected jellyfish.

Relation to humans
Jellyfish have long been eaten in some parts of the world. Fisheries have begun harvesting the American cannonball jellyfish, Stomolophus meleagris, along the southern Atlantic coast of the United States and in the Gulf of Mexico for export to Asia.

Jellyfish are also harvested for their collagen, which is being investigated for use in a variety of applications including the treatment of rheumatoid arthritis.

Aquaculture and fisheries of other species often suffer severe losses – and so losses of productivity – due to jellyfish.

Products
Main article: Jellyfish as food
In some countries, including China, Japan, and Korea, jellyfish are a delicacy. The jellyfish is dried to prevent spoiling. Only some 12 species of scyphozoan jellyfish belonging to the order Rhizostomeae are harvested for food, mostly in southeast Asia. Rhizostomes, especially Rhopilema esculentum in China (海蜇 hǎizhé, 'sea stingers') and Stomolophus meleagris (cannonball jellyfish) in the United States, are favored because of their larger and more rigid bodies and because their toxins are harmless to humans.

Traditional processing methods, carried out by a jellyfish master, involve a 20- to 40-day multi-phase procedure in which, after removing the gonads and mucous membranes, the umbrella and oral arms are treated with a mixture of table salt and alum, and compressed. Processing makes the jellyfish drier and more acidic, producing a crisp texture. Jellyfish prepared this way retain 7–10% of their original weight, and the processed product consists of approximately 94% water and 6% protein. Freshly processed jellyfish has a white, creamy color and turns yellow or brown during prolonged storage.

In China, processed jellyfish are desalted by soaking in water overnight and eaten cooked or raw. The dish is often served shredded with a dressing of oil, soy sauce, vinegar and sugar, or as a salad with vegetables. In Japan, cured jellyfish are rinsed, cut into strips and served with vinegar as an appetizer. Desalted, ready-to-eat products are also available.

Biotechnology
The hydromedusa Aequorea victoria was the source of green fluorescent protein, studied for its role in bioluminescence and later for use as a marker in genetic engineering.
Pliny the Elder reported in his Natural History that the slime of the jellyfish "Pulmo marinus" produced light when rubbed on a walking stick.

In 1961, Osamu Shimomura extracted green fluorescent protein (GFP) and another bioluminescent protein, called aequorin, from the large and abundant hydromedusa Aequorea victoria, while studying photoproteins that cause bioluminescence in this species. Three decades later, Douglas Prasher sequenced and cloned the gene for GFP. Martin Chalfie figured out how to use GFP as a fluorescent marker of genes inserted into other cells or organisms. Roger Tsien later chemically manipulated GFP to produce other fluorescent colors to use as markers. In 2008, Shimomura, Chalfie and Tsien won the Nobel Prize in Chemistry for their work with GFP. Man-made GFP became widely used as a fluorescent tag to show which cells or tissues express specific genes. The genetic engineering technique fuses the gene of interest to the GFP gene. The fused DNA is then put into a cell, to generate either a cell line or (via IVF techniques) an entire animal bearing the gene. In the cell or animal, the artificial gene turns on in the same tissues and the same time as the normal gene, making a fusion of the normal protein with GFP attached to the end, illuminating the animal or cell reveals what tissues express that protein—or at what stage of development. The fluorescence shows where the gene is expressed.

Aquarium display
Jellyfish are displayed in many public aquariums. Often the tank's background is blue and the animals are illuminated by side light, increasing the contrast between the animal and the background. In natural conditions, many jellies are so transparent that they are nearly invisible. Jellyfish are not adapted to closed spaces. They depend on currents to transport them from place to place. Professional exhibits as in the Monterey Bay Aquarium feature precise water flows, typically in circular tanks to avoid trapping specimens in corners. The outflow is spread out over a large surface area and the inflow enters as a sheet of water in front of the outflow, so the jellyfish do not get sucked into it. As of 2009, jellyfish were becoming popular in home aquariums, where they require similar equipment.

Stings
Jellyfish are armed with nematocysts, a type of specialized stinging cell. Contact with a jellyfish tentacle can trigger millions of nematocysts to pierce the skin and inject venom, but only some species' venom causes an adverse reaction in humans. In a study published in Communications Biology, researchers found a jellyfish species called Cassiopea xamachana which when triggered will release tiny balls of cells that swim around the jellyfish stinging everything in their path. Researchers described these as "self-propelling microscopic grenades" and named them cassiosomes.

The effects of stings range from mild discomfort to extreme pain and death. Most jellyfish stings are not deadly, but stings of some box jellyfish (Irukandji jellyfish), such as the sea wasp, can be deadly. Stings may cause anaphylaxis (a form of shock), which can be fatal. Jellyfish kill 20 to 40 people a year in the Philippines alone. In 2006 the Spanish Red Cross treated 19,000 stung swimmers along the Costa Brava.

Vinegar (3–10% aqueous acetic acid) may help with box jellyfish stings but not the stings of the Portuguese man o' war. Clearing the area of jelly and tentacles reduces nematocyst firing. Scraping the affected skin, such as with the edge of a credit card, may remove remaining nematocysts. Once the skin has been cleaned of nematocysts, hydrocortisone cream applied locally reduces pain and inflammation. Antihistamines may help to control itching. Immunobased antivenins are used for serious box jellyfish stings.

In Elba Island and Corsica dittrichia viscosa is now used by residents and tourists to heal stings from jellyfish, bees and wasps pressing fresh leaves on the skin with quick results.

Mechanical issues
Jellyfish in large quantities can fill and split fishing nets and crush captured fish. They can clog cooling equipment, having disabled power stations in several countries; jellyfish caused a cascading blackout in the Philippines in 1999, as well as damaging the Diablo Canyon Power Plant in California in 2008. They can also stop desalination plants and ships' engines.

Jellyfish - Sea Jellies - Medusa (Subphylum Medusozoa) by millicand@rocketmail.com

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Jellyfish - Sea Jellies - Medusa (Subphylum Medusozoa)

Jellyfish, also known sea jellies, are the medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria.

Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles, although a few are anchored to the seabed by stalks rather than being mobile. The bell can pulsate to provide propulsion for highly efficient locomotion. The tentacles are armed with stinging cells and may be used to capture prey and defend against predators. Jellyfish have a complex life cycle. The medusa is normally the sexual phase, which produces planula larvae; these then disperse widely and enter a sedentary polyp phase, before reaching sexual maturity.

Jellyfish are found all over the world, from surface waters to the deep sea. Scyphozoans (the "true jellyfish") are exclusively marine, but some hydrozoans with a similar appearance live in freshwater. Large, often colorful, jellyfish are common in coastal zones worldwide. The medusae of most species are fast-growing, and mature within a few months then die soon after breeding, but the polyp stage, attached to the seabed, may be much more long-lived. Jellyfish have been in existence for at least 500 million years, and possibly 700 million years or more, making them the oldest multi-organ animal group.

Jellyfish are eaten by humans in certain cultures. They are considered a delicacy in some Asian countries, where species in the Rhizostomeae order are pressed and salted to remove excess water. Australian researchers have described them as a "perfect food": sustainable and protein-rich but relatively low in food energy.

They are also used in research, where the green fluorescent protein used by some species to cause bioluminescence has been adapted as a fluorescent marker for genes inserted into other cells or organisms.

The stinging cells used by jellyfish to subdue their prey can injure humans. Thousands of swimmers worldwide are stung every year, with effects ranging from mild discomfort to serious injury or even death. When conditions are favourable, jellyfish can form vast swarms, which can be responsible for damage to fishing gear by filling fishing nets, and sometimes clog the cooling systems of power and desalination plants which draw their water from the sea.


Names
The name jellyfish, in use since 1796, has traditionally been applied to medusae and all similar animals including the comb jellies (ctenophores, another phylum). The term jellies or sea jellies is more recent, having been introduced by public aquaria in an effort to avoid use of the word "fish" with its modern connotation of an animal with a backbone, though shellfish, cuttlefish and starfish are not vertebrates either. In scientific literature, "jelly" and "jellyfish" have been used interchangeably. Many sources refer to only scyphozoans as "true jellyfish".

A group of jellyfish is called a "smack" or a "smuck".

Definition
The term jellyfish broadly corresponds to medusae, that is, a life-cycle stage in the Medusozoa. The American evolutionary biologist Paulyn Cartwright gives the following general definition:

Typically, medusozoan cnidarians have a pelagic, predatory jellyfish stage in their life cycle; staurozoans are the exceptions [as they are stalked].

The Merriam-Webster dictionary defines jellyfish as follows:

A free-swimming marine coelenterate that is the sexually reproducing form of a hydrozoan or scyphozoan and has a nearly transparent saucer-shaped body and extensible marginal tentacles studded with stinging cells.

Given that jellyfish is a common name, its mapping to biological groups is inexact. Some authorities have called the comb jellies and certain salps jellyfish, though other authorities state that neither of these are jellyfish, which they consider should be limited to certain groups within the medusozoa.

The non-medusozoan clades called jellyfish by some but not all authorities (both agreeing and disagreeing citations are given in each case) are indicated with on the following cladogram of the animal kingdom:

Jellyfish are not a clade, as they include most of the Medusozoa, barring some of the Hydrozoa. The medusozoan groups included by authorities are indicated on the following phylogenetic tree by the presence of citations. Names of included jellyfish, in English where possible, are shown in boldface; the presence of a named and cited example indicates that at least that species within its group has been called a jellyfish.

Taxonomy
The subphylum Medusozoa includes all cnidarians with a medusa stage in their life cycle. The basic cycle is egg, planula larva, polyp, medusa, with the medusa being the sexual stage. The polyp stage is sometimes secondarily lost. The subphylum include the major taxa, Scyphozoa (large jellyfish), Cubozoa (box jellyfish) and Hydrozoa (small jellyfish), and excludes Anthozoa (corals and sea anemones). This suggests that the medusa form evolved after the polyps. Medusozoans have tetramerous symmetry, with parts in fours or multiples of four.

The four major classes of medusozoan Cnidaria are:
Scyphozoa are sometimes called true jellyfish, though they are no more truly jellyfish than the others listed here. They have tetra-radial symmetry. Most have tentacles around the outer margin of the bowl-shaped bell, and long, oral arms around the mouth in the center of the subumbrella.
Cubozoa (box jellyfish) have a (rounded) box-shaped bell, and their velarium assists them to swim more quickly. Box jellyfish may be related more closely to scyphozoan jellyfish than either are to the Hydrozoa.
Hydrozoa medusae also have tetra-radial symmetry, nearly always have a velum (diaphragm used in swimming) attached just inside the bell margin, do not have oral arms, but a much smaller central stalk-like structure, the manubrium, with terminal mouth opening, and are distinguished by the absence of cells in the mesoglea. Hydrozoa show great diversity of lifestyle; some species maintain the polyp form for their entire life and do not form medusae at all (such as Hydra, which is hence not considered a jellyfish), and a few are entirely medusal and have no polyp form.
Staurozoa (stalked jellyfish) are characterized by a medusa form that is generally sessile, oriented upside down and with a stalk emerging from the apex of the "calyx" (bell), which attaches to the substrate. At least some Staurozoa also have a polyp form that alternates with the medusoid portion of the life cycle. Until recently, Staurozoa were classified within the Scyphozoa.
There are over 200 species of Scyphozoa, about 50 species of Staurozoa, about 50 species of Cubozoa, and the Hydrozoa includes about 1000–1500 species that produce medusae, but many more species that do not.

Fossil history
Since jellyfish have no hard parts, fossils are rare. The oldest unambiguous fossil of a free-swimming medusa is Burgessomedusa from the mid Cambrian Burgess Shale of Canada, which is likely either a stem group of box jellyfish (Cubozoa) or Acraspeda (the clade including Staurozoa, Cubozoa, and Scyphozoa). Other claimed records from the Cambrian of China and Utah in the United States are uncertain, and possibly represent ctenophores instead.

Anatomy
The main feature of a true jellyfish is the umbrella-shaped bell. This is a hollow structure consisting of a mass of transparent jelly-like matter known as mesoglea, which forms the hydrostatic skeleton of the animal. 95% or more of the mesogloea consists of water, but it also contains collagen and other fibrous proteins, as well as wandering amoebocytes which can engulf debris and bacteria. The mesogloea is bordered by the epidermis on the outside and the gastrodermis on the inside. The edge of the bell is often divided into rounded lobes known as lappets, which allow the bell to flex. In the gaps or niches between the lappets are dangling rudimentary sense organs known as rhopalia, and the margin of the bell often bears tentacles.


Anatomy of a scyphozoan jellyfish
On the underside of the bell is the manubrium, a stalk-like structure hanging down from the centre, with the mouth, which also functions as the anus, at its tip. There are often four oral arms connected to the manubrium, streaming away into the water below. The mouth opens into the gastrovascular cavity, where digestion takes place and nutrients are absorbed. This is subdivided by four thick septa into a central stomach and four gastric pockets. The four pairs of gonads are attached to the septa, and close to them four septal funnels open to the exterior, perhaps supplying good oxygenation to the gonads. Near the free edges of the septa, gastric filaments extend into the gastric cavity; these are armed with nematocysts and enzyme-producing cells and play a role in subduing and digesting the prey. In some scyphozoans, the gastric cavity is joined to radial canals which branch extensively and may join a marginal ring canal. Cilia in these canals circulate the fluid in a regular direction.


Discharge mechanism of a nematocyst
The box jellyfish is largely similar in structure. It has a squarish, box-like bell. A short pedalium or stalk hangs from each of the four lower corners. One or more long, slender tentacles are attached to each pedalium. The rim of the bell is folded inwards to form a shelf known as a velarium which restricts the bell's aperture and creates a powerful jet when the bell pulsates, allowing box jellyfish to swim faster than true jellyfish. Hydrozoans are also similar, usually with just four tentacles at the edge of the bell, although many hydrozoans are colonial and may not have a free-living medusal stage. In some species, a non-detachable bud known as a gonophore is formed that contains a gonad but is missing many other medusal features such as tentacles and rhopalia. Stalked jellyfish are attached to a solid surface by a basal disk, and resemble a polyp, the oral end of which has partially developed into a medusa with tentacle-bearing lobes and a central manubrium with four-sided mouth.

Most jellyfish do not have specialized systems for osmoregulation, respiration and circulation, and do not have a central nervous system. Nematocysts, which deliver the sting, are located mostly on the tentacles; true jellyfish also have them around the mouth and stomach. Jellyfish do not need a respiratory system because sufficient oxygen diffuses through the epidermis. They have limited control over their movement, but can navigate with the pulsations of the bell-like body; some species are active swimmers most of the time, while others largely drift. The rhopalia contain rudimentary sense organs which are able to detect light, water-borne vibrations, odour and orientation. A loose network of nerves called a "nerve net" is located in the epidermis. Although traditionally thought not to have a central nervous system, nerve net concentration and ganglion-like structures could be considered to constitute one in most species. A jellyfish detects stimuli, and transmits impulses both throughout the nerve net and around a circular nerve ring, to other nerve cells. The rhopalial ganglia contain pacemaker neurones which control swimming rate and direction.

In many species of jellyfish, the rhopalia include ocelli, light-sensitive organs able to tell light from dark. These are generally pigment spot ocelli, which have some of their cells pigmented. The rhopalia are suspended on stalks with heavy crystals at one end, acting like gyroscopes to orient the eyes skyward. Certain jellyfish look upward at the mangrove canopy while making a daily migration from mangrove swamps into the open lagoon, where they feed, and back again.

Box jellyfish have more advanced vision than the other groups. Each individual has 24 eyes, two of which are capable of seeing colour, and four parallel information processing areas that act in competition, supposedly making them one of the few kinds of animal to have a 360-degree view of its environment.

Box jellyfish eye
The study of jellyfish eye evolution is an intermediary to a better understanding of how visual systems evolved on Earth. Jellyfish exhibit immense variation in visual systems ranging from photoreceptive cell patches seen in simple photoreceptive systems to more derived complex eyes seen in box jellyfish. Major topics of jellyfish visual system research (with an emphasis on box jellyfish) include: the evolution of jellyfish vision from simple to complex visual systems), the eye morphology and molecular structures of box jellyfish (including comparisons to vertebrate eyes), and various uses of vision including task-guided behaviors and niche specialization.

Evolution
Experimental evidence for photosensitivity and photoreception in cnidarians antecedes the mid 1900s, and a rich body of research has since covered evolution of visual systems in jellyfish. Jellyfish visual systems range from simple photoreceptive cells to complex image-forming eyes. More ancestral visual systems incorporate extraocular vision (vision without eyes) that encompass numerous receptors dedicated to single-function behaviors. More derived visual systems comprise perception that is capable of multiple task-guided behaviors.

Although they lack a true brain, cnidarian jellyfish have a "ring" nervous system that plays a significant role in motor and sensory activity. This net of nerves is responsible for muscle contraction and movement and culminates the emergence of photosensitive structures. Across Cnidaria, there is large variation in the systems that underlie photosensitivity. Photosensitive structures range from non-specialized groups of cells, to more "conventional" eyes similar to those of vertebrates. The general evolutionary steps to develop complex vision include (from more ancestral to more derived states): non-directional photoreception, directional photoreception, low-resolution vision, and high-resolution vision. Increased habitat and task complexity has favored the high-resolution visual systems common in derived cnidarians such as box jellyfish.

Basal visual systems observed in various cnidarians exhibit photosensitivity representative of a single task or behavior. Extraocular photoreception (a form of non-directional photoreception), is the most basic form of light sensitivity and guides a variety of behaviors among cnidarians. It can function to regulate circadian rhythm (as seen in eyeless hydrozoans) and other light-guided behaviors responsive to the intensity and spectrum of light. Extraocular photoreception can function additionally in positive phototaxis (in planula larvae of hydrozoans), as well as in avoiding harmful amounts of UV radiation via negative phototaxis. Directional photoreception (the ability to perceive direction of incoming light) allows for more complex phototactic responses to light, and likely evolved by means of membrane stacking. The resulting behavioral responses can range from guided spawning events timed by moonlight to shadow responses for potential predator avoidance. Light-guided behaviors are observed in numerous scyphozoans including the common moon jelly, Aurelia aurita, which migrates in response to changes in ambient light and solar position even though they lack proper eyes.

The low-resolution visual system of box jellyfish is more derived than directional photoreception, and thus box jellyfish vision represents the most basic form of true vision in which multiple directional photoreceptors combine to create the first imaging and spatial resolution. This is different from the high-resolution vision that is observed in camera or compound eyes of vertebrates and cephalopods that rely on focusing optics. Critically, the visual systems of box jellyfish are responsible for guiding multiple tasks or behaviors in contrast to less derived visual systems in other jellyfish that guide single behavioral functions. These behaviors include phototaxis based on sunlight (positive) or shadows (negative), obstacle avoidance, and control of swim-pulse rate.

Box jellyfish possess "proper eyes" (similar to vertebrates) that allow them to inhabit environments that lesser derived medusae cannot. In fact, they are considered the only class in the clade Medusozoa that have behaviors necessitating spatial resolution and genuine vision. However, the lens in their eyes are more functionally similar to cup-eyes exhibited in low-resolution organisms, and have very little to no focusing capability. The lack of the ability to focus is due to the focal length exceeding the distance to the retina, thus generating unfocused images and limiting spatial resolution. The visual system is still sufficient for box jellyfish to produce an image to help with tasks such as object avoidance.

Utility as a model organism
Box jellyfish eyes are a visual system that is sophisticated in numerous ways. These intricacies include the considerable variation within the morphology of box jellyfishes' eyes (including their task/behavior specification), and the molecular makeup of their eyes including: photoreceptors, opsins, lenses, and synapses. The comparison of these attributes to more derived visual systems can allow for a further understanding of how the evolution of more derived visual systems may have occurred, and puts into perspective how box jellyfish can play the role as an evolutionary/developmental model for all visual systems.

Characteristics
Box jellyfish visual systems are both diverse and complex, comprising multiple photosystems. There is likely considerable variation in visual properties between species of box jellyfish given the significant inter-species morphological and physiological variation. Eyes tend to differ in size and shape, along with number of receptors (including opsins), and physiology across species of box jellyfish.

Box jellyfish have a series of intricate lensed eyes that are similar to those of more derived multicellular organisms such as vertebrates. Their 24 eyes fit into four different morphological categories. These categories consist of two large, morphologically different medial eyes (a lower and upper lensed eye) containing spherical lenses, a lateral pair of pigment slit eyes, and a lateral pair of pigment pit eyes. The eyes are situated on rhopalia (small sensory structures) which serve sensory functions of the box jellyfish and arise from the cavities of the exumbrella (the surface of the body) on the side of the bells of the jellyfish. The two large eyes are located on the mid-line of the club and are considered complex because they contain lenses. The four remaining eyes lie laterally on either side of each rhopalia and are considered simple. The simple eyes are observed as small invaginated cups of epithelium that have developed pigmentation. The larger of the complex eyes contains a cellular cornea created by a mono ciliated epithelium, cellular lens, homogenous capsule to the lens, vitreous body with prismatic elements, and a retina of pigmented cells. The smaller of the complex eyes is said to be slightly less complex given that it lacks a capsule but otherwise contains the same structure as the larger eye.

Box jellyfish have multiple photosystems that comprise different sets of eyes. Evidence includes immunocytochemical and molecular data that show photopigment differences among the different morphological eye types, and physiological experiments done on box jellyfish to suggest behavioral differences among photosystems. Each individual eye type constitutes photosystems that work collectively to control visually guided behaviors.

Box jellyfish eyes primarily use c-PRCs (ciliary photoreceptor cells) similar to that of vertebrate eyes. These cells undergo phototransduction cascades (process of light absorption by photoreceptors) that are triggered by c-opsins. Available opsin sequences suggest that there are two types of opsins possessed by all cnidarians including an ancient phylogenetic opsin, and a sister ciliary opsin to the c-opsins group. Box jellyfish could have both ciliary and cnidops (cnidarian opsins), which is something not previously believed to appear in the same retina. Nevertheless, it is not entirely evident whether cnidarians possess multiple opsins that are capable of having distinctive spectral sensitivities.

Comparison with other organisms
Comparative research on genetic and molecular makeup of box jellyfishes' eyes versus more derived eyes seen in vertebrates and cephalopods focuses on: lenses and crystallin composition, synapses, and Pax genes and their implied evidence for shared primordial (ancestral) genes in eye evolution.

Box jellyfish eyes are said to be an evolutionary/developmental model of all eyes based on their evolutionary recruitment of crystallins and Pax genes. Research done on box jellyfish including Tripedalia cystophora has suggested that they possess a single Pax gene, PaxB. PaxB functions by binding to crystallin promoters and activating them. PaxB in situ hybridization resulted in PaxB expression in the lens, retina, and statocysts. These results and the rejection of the prior hypothesis that Pax6 was an ancestral Pax gene in eyes has led to the conclusion that PaxB was a primordial gene in eye evolution, and that the eyes of all organisms likely share a common ancestor.

The lens structure of box jellyfish appears very similar to those of other organisms, but the crystallins are distinct in both function and appearance. Weak reactions were seen within the sera and there were very weak sequence similarities within the crystallins among vertebrate and invertebrate lenses. This is likely due to differences in lower molecular weight proteins and the subsequent lack of immunological reactions with antisera that other organisms' lenses exhibit.

All four of the visual systems of box jellyfish species investigated with detail (Carybdea marsupialis, Chiropsalmus quadrumanus, Tamoya haplonema and Tripedalia cystophora) have invaginated synapses, but only in the upper and lower lensed eyes. Different densities were found between the upper and lower lenses, and between species. Four types of chemical synapses have been discovered within the rhopalia which could help in understanding neural organization including: clear unidirectional, dense-core unidirectional, clear bidirectional, and clear and dense-core bidirectional. The synapses of the lensed eyes could be useful as markers to learn more about the neural circuit in box jellyfish retinal areas.

Evolution as a response to natural stimuli
The primary adaptive responses to environmental variation observed in box jellyfish eyes include pupillary constriction speeds in response to light environments, as well as photoreceptor tuning and lens adaptations to better respond to shifts between light environments and darkness. Interestingly, some box jellyfish species' eyes appear to have evolved more focused vision in response to their habitat.

Pupillary contraction appears to have evolved in response to variation in the light environment across ecological niches across three species of box jellyfish (Chironex fleckeri, Chiropsella bronzie, and Carukia barnesi). Behavioral studies suggest that faster pupil contraction rates allow for greater object avoidance, and in fact, species with more complex habitats exhibit faster rates. Ch. bronzie inhabit shallow beach fronts that have low visibility and very few obstacles, thus, faster pupil contraction in response to objects in their environment is not important. Ca. barnesi and Ch. fleckeri are found in more three-dimensionally complex environments like mangroves with an abundance of natural obstacles, where faster pupil contraction is more adaptive. Behavioral studies support the idea that faster pupillary contraction rates assist with obstacle avoidance as well as depth adjustments in response to differing light intensities.

Light/dark adaptation via pupillary light reflexes is an additional form of an evolutionary response to the light environment. This relates to the pupil's response to shifts between light intensity (generally from sunlight to darkness). In the process of light/dark adaptation, the upper and lower lens eyes of different box jellyfish species vary in specific function. The lower lens-eyes contain pigmented photoreceptors and long pigment cells with dark pigments that migrate on light/dark adaptation, while the upper-lens eyes play a concentrated role in light direction and phototaxis given that they face upward towards the water surface (towards the sun or moon). The upper lens of Ch. bronzie does not exhibit any considerable optical power while Tr. cystophora (a box jellyfish species that tends to live in mangroves) does. The ability to use light to visually guide behavior is not of as much importance to Ch. bronzie as it is to species in more obstacle-filled environments. Differences in visually guided behavior serve as evidence that species that share the same number and structure of eyes can exhibit differences in how they control behavior.

Largest and smallest
Jellyfish range from about one millimeter in bell height and diameter, to nearly 2 metres (6+1⁄2 ft) in bell height and diameter; the tentacles and mouth parts usually extend beyond this bell dimension.

The smallest jellyfish are the peculiar creeping jellyfish in the genera Staurocladia and Eleutheria, which have bell disks from 0.5 millimetres (1⁄32 in) to a few millimeters in diameter, with short tentacles that extend out beyond this, which these jellyfish use to move across the surface of seaweed or the bottoms of rocky pools; many of these tiny creeping jellyfish cannot be seen in the field without a hand lens or microscope. They can reproduce asexually by fission (splitting in half). Other very small jellyfish, which have bells about one millimeter, are the hydromedusae of many species that have just been released from their parent polyps; some of these live only a few minutes before shedding their gametes in the plankton and then dying, while others will grow in the plankton for weeks or months. The hydromedusae Cladonema radiatum and Cladonema californicum are also very small, living for months, yet never growing beyond a few mm in bell height and diameter.

The lion's mane jellyfish, Cyanea capillata, was long-cited as the largest jellyfish, and arguably the longest animal in the world, with fine, thread-like tentacles that may extend up to 36.5 m (119 ft 9 in) long (though most are nowhere near that large). They have a moderately painful, but rarely fatal, sting. The increasingly common giant Nomura's jellyfish, Nemopilema nomurai, found in some, but not all years in the waters of Japan, Korea and China in summer and autumn is another candidate for "largest jellyfish", in terms of diameter and weight, since the largest Nomura's jellyfish in late autumn can reach 2 m (6 ft 7 in) in bell (body) diameter and about 200 kg (440 lb) in weight, with average specimens frequently reaching 0.9 m (2 ft 11 in) in bell diameter and about 150 kg (330 lb) in weight. The large bell mass of the giant Nomura's jellyfish can dwarf a diver and is nearly always much greater than the Lion's Mane, whose bell diameter can reach 1 m (3 ft 3 in).

The rarely encountered deep-sea jellyfish Stygiomedusa gigantea is another candidate for "largest jellyfish", with its thick, massive bell up to 100 cm (3 ft 3 in) wide, and four thick, "strap-like" oral arms extending up to 6 m (19+1⁄2 ft) in length, very different from the typical fine, threadlike tentacles that rim the umbrella of more-typical-looking jellyfish, including the Lion's Mane.

Desmonema glaciale, which lives in the Antarctic region, can reach a very large size (several meters). Purple-striped jelly (Chrysaora colorata) can also be extremely long (up to 15 feet).

Life history and behavior
Life cycle
Jellyfish have a complex life cycle which includes both sexual and asexual phases, with the medusa being the sexual stage in most instances. Sperm fertilize eggs, which develop into larval planulae, become polyps, bud into ephyrae and then transform into adult medusae. In some species certain stages may be skipped.

Upon reaching adult size, jellyfish spawn regularly if there is a sufficient supply of food. In most species, spawning is controlled by light, with all individuals spawning at about the same time of day; in many instances this is at dawn or dusk. Jellyfish are usually either male or female (with occasional hermaphrodites). In most cases, adults release sperm and eggs into the surrounding water, where the unprotected eggs are fertilized and develop into larvae. In a few species, the sperm swim into the female's mouth, fertilizing the eggs within her body, where they remain during early development stages. In moon jellies, the eggs lodge in pits on the oral arms, which form a temporary brood chamber for the developing planula larvae.

The planula is a small larva covered with cilia. When sufficiently developed, it settles onto a firm surface and develops into a polyp. The polyp generally consists of a small stalk topped by a mouth that is ringed by upward-facing tentacles. The polyps resemble those of closely related anthozoans, such as sea anemones and corals. The jellyfish polyp may be sessile, living on the bottom, boat hulls or other substrates, or it may be free-floating or attached to tiny bits of free-living plankton or rarely, fish or other invertebrates. Polyps may be solitary or colonial. Most polyps are only millimetres in diameter and feed continuously. The polyp stage may last for years.

After an interval and stimulated by seasonal or hormonal changes, the polyp may begin reproducing asexually by budding and, in the Scyphozoa, is called a segmenting polyp, or a scyphistoma. Budding produces more scyphistomae and also ephyrae. Budding sites vary by species; from the tentacle bulbs, the manubrium (above the mouth), or the gonads of hydromedusae. In a process known as strobilation, the polyp's tentacles are reabsorbed and the body starts to narrow, forming transverse constrictions, in several places near the upper extremity of the polyp. These deepen as the constriction sites migrate down the body, and separate segments known as ephyra detach. These are free-swimming precursors of the adult medusa stage, which is the life stage that is typically identified as a jellyfish. The ephyrae, usually only a millimeter or two across initially, swim away from the polyp and grow. Limnomedusae polyps can asexually produce a creeping frustule larval form, which crawls away before developing into another polyp. A few species can produce new medusae by budding directly from the medusan stage. Some hydromedusae reproduce by fission.

Lifespan
Little is known of the life histories of many jellyfish as the places on the seabed where the benthic forms of those species live have not been found. However, an asexually reproducing strobila form can sometimes live for several years, producing new medusae (ephyra larvae) each year.

An unusual species, Turritopsis dohrnii, formerly classified as Turritopsis nutricula, might be effectively immortal because of its ability under certain circumstances to transform from medusa back to the polyp stage, thereby escaping the death that typically awaits medusae post-reproduction if they have not otherwise been eaten by some other organism. So far this reversal has been observed only in the laboratory.

Locomotion
Jellyfish locomotion is highly efficient. Muscles in the jellylike bell contract, setting up a start vortex and propelling the animal. When the contraction ends, the bell recoils elastically, creating a stop vortex with no extra energy input.
Using the moon jelly Aurelia aurita as an example, jellyfish have been shown to be the most energy-efficient swimmers of all animals. They move through the water by radially expanding and contracting their bell-shaped bodies to push water behind them. They pause between the contraction and expansion phases to create two vortex rings. Muscles are used for the contraction of the body, which creates the first vortex and pushes the animal forward, but the mesoglea is so elastic that the expansion is powered exclusively by relaxing the bell, which releases the energy stored from the contraction. Meanwhile, the second vortex ring starts to spin faster, sucking water into the bell and pushing against the centre of the body, giving a secondary and "free" boost forward. The mechanism, called passive energy recapture, only works in relatively small jellyfish moving at low speeds, allowing the animal to travel 30 percent farther on each swimming cycle. Jellyfish achieved a 48 percent lower cost of transport (food and oxygen intake versus energy spent in movement) than other animals in similar studies. One reason for this is that most of the gelatinous tissue of the bell is inactive, using no energy during swimming.

Ecology
Diet
Jellyfish are, like other cnidarians, generally carnivorous (or parasitic), feeding on planktonic organisms, crustaceans, small fish, fish eggs and larvae, and other jellyfish, ingesting food and voiding undigested waste through the mouth. They hunt passively using their tentacles as drift lines, or sink through the water with their tentacles spread widely; the tentacles, which contain nematocysts to stun or kill the prey, may then flex to help bring it to the mouth. Their swimming technique also helps them to capture prey; when their bell expands it sucks in water which brings more potential prey within reach of the tentacles.

A few species such as Aglaura hemistoma are omnivorous, feeding on microplankton which is a mixture of zooplankton and phytoplankton (microscopic plants) such as dinoflagellates. Others harbour mutualistic algae (Zooxanthellae) in their tissues; the spotted jellyfish (Mastigias papua) is typical of these, deriving part of its nutrition from the products of photosynthesis, and part from captured zooplankton. The upside-down jellyfish (Cassiopea andromeda) also has a symbiotic relationship with microalgae, but captures tiny animals to supplement their diet. This is done by releasing tiny balls of living cells composed of mesoglea. These use cilia to drive them through water and stinging cells which stun the prey. The blobs also seems to have digestive capabilities.

Predation
Other species of jellyfish are among the most common and important jellyfish predators. Sea anemones may eat jellyfish that drift into their range. Other predators include tunas, sharks, swordfish, sea turtles and penguins. Jellyfish washed up on the beach are consumed by foxes, other terrestrial mammals and birds. In general however, few animals prey on jellyfish; they can broadly be considered to be top predators in the food chain. Once jellyfish have become dominant in an ecosystem, for example through overfishing which removes predators of jellyfish larvae, there may be no obvious way for the previous balance to be restored: they eat fish eggs and juvenile fish, and compete with fish for food, preventing fish stocks from recovering.

Symbiosis
Some small fish are immune to the stings of the jellyfish and live among the tentacles, serving as bait in a fish trap; they are safe from potential predators and are able to share the fish caught by the jellyfish. The cannonball jellyfish has a symbiotic relationship with ten different species of fish, and with the longnose spider crab, which lives inside the bell, sharing the jellyfish's food and nibbling its tissues.

Main article: Jellyfish bloom
Jellyfish form large masses or blooms in certain environmental conditions of ocean currents, nutrients, sunshine, temperature, season, prey availability, reduced predation and oxygen concentration. Currents collect jellyfish together, especially in years with unusually high populations. Jellyfish can detect marine currents and swim against the current to congregate in blooms. Jellyfish are better able to survive in nutrient-rich, oxygen-poor water than competitors, and thus can feast on plankton without competition. Jellyfish may also benefit from saltier waters, as saltier waters contain more iodine, which is necessary for polyps to turn into jellyfish. Rising sea temperatures caused by climate change may also contribute to jellyfish blooms, because many species of jellyfish are able to survive in warmer waters. Increased nutrients from agricultural or urban runoff with nutrients including nitrogen and phosphorus compounds increase the growth of phytoplankton, causing eutrophication and algal blooms. When the phytoplankton die, they may create dead zones, so-called because they are hypoxic (low in oxygen). This in turn kills fish and other animals, but not jellyfish, allowing them to bloom. Jellyfish populations may be expanding globally as a result of land runoff and overfishing of their natural predators. Jellyfish are well placed to benefit from disturbance of marine ecosystems. They reproduce rapidly; they prey upon many species, while few species prey on them; and they feed via touch rather than visually, so they can feed effectively at night and in turbid waters. It may be difficult for fish stocks to re-establish themselves in marine ecosystems once they have become dominated by jellyfish, because jellyfish feed on plankton, which includes fish eggs and larvae.

As suspected at the turn of this century, jellyfish blooms are increasing in frequency. Between 2013 and 2020 the Mediterranean Science Commission monitored on a weekly basis the frequency of such outbreaks in coastal waters from Morocco to the Black Sea, revealing a relatively high frequency of these blooms nearly all year round, with peaks observed from March to July and often again in the autumn. The blooms are caused by different jellyfish species, depending on their localisation within the Basin: one observes a clear dominance of Pelagia noctiluca and Velella velella outbreaks in the western Mediterranean, of Rhizostoma pulmo and Rhopilema nomadica outbreaks in the eastern Mediterranean, and of Aurelia aurita and Mnemiopsis leidyi outbreaks in the Black Sea.

Some jellyfish populations that have shown clear increases in the past few decades are invasive species, newly arrived from other habitats: examples include the Black Sea, Caspian Sea, Baltic Sea, central and eastern Mediterranean, Hawaii, and tropical and subtropical parts of the West Atlantic (including the Caribbean, Gulf of Mexico and Brazil).

Jellyfish blooms can have significant impact on community structure. Some carnivorous jellyfish species prey on zooplankton while others graze on primary producers. Reductions in zooplankton and ichthyoplankton due to a jellyfish bloom can ripple through the trophic levels. High-density jellyfish populations can outcompete other predators and reduce fish recruitment. Increased grazing on primary producers by jellyfish can also interrupt energy transfer to higher trophic levels.

During blooms, jellyfish significantly alter the nutrient availability in their environment. Blooms require large amounts of available organic nutrients in the water column to grow, limiting availability for other organisms. Some jellyfish have a symbiotic relationship with single-celled dinoflagellates, allowing them to assimilate inorganic carbon, phosphorus, and nitrogen creating competition for phytoplankton. Their large biomass makes them an important source of dissolved and particulate organic matter for microbial communities through excretion, mucus production, and decomposition. The microbes break down the organic matter into inorganic ammonium and phosphate. However, the low carbon availability shifts the process from production to respiration creating low oxygen areas making the dissolved inorganic nitrogen and phosphorus largely unavailable for primary production.

These blooms have very real impacts on industries. Jellyfish can outcompete fish by utilizing open niches in over-fished fisheries. Catch of jellyfish can strain fishing gear and lead to expenses relating to damaged gear. Power plants have been shut down due to jellyfish blocking the flow of cooling water. Blooms have also been harmful for tourism, causing a rise in stings and sometimes the closure of beaches.

Jellyfish form a component of jelly-falls, events where gelatinous zooplankton fall to the seafloor, providing food for the benthic organisms there. In temperate and subpolar regions, jelly-falls usually follow immediately after a bloom.

Habitats
Most jellyfish are marine animals, although a few hydromedusae inhabit freshwater. The best known freshwater example is the cosmopolitan hydrozoan jellyfish, Craspedacusta sowerbii. It is less than an inch (2.5 cm) in diameter, colorless and does not sting. Some jellyfish populations have become restricted to coastal saltwater lakes, such as Jellyfish Lake in Palau. Jellyfish Lake is a marine lake where millions of golden jellyfish (Mastigias spp.) migrate horizontally across the lake daily.

Although most jellyfish live well off the ocean floor and form part of the plankton, a few species are closely associated with the bottom for much of their lives and can be considered benthic. The upside-down jellyfish in the genus Cassiopea typically lie on the bottom of shallow lagoons where they sometimes pulsate gently with their umbrella top facing down. Even some deep-sea species of hydromedusae and scyphomedusae are usually collected on or near the bottom. All of the stauromedusae are found attached to either seaweed or rocky or other firm material on the bottom.

Some species explicitly adapt to tidal flux. In Roscoe Bay, jellyfish ride the current at ebb tide until they hit a gravel bar, and then descend below the current. They remain in still waters until the tide rises, ascending and allowing it to sweep them back into the bay. They also actively avoid fresh water from mountain snowmelt, diving until they find enough salt.


Parasites
Jellyfish are hosts to a wide variety of parasitic organisms. They act as intermediate hosts of endoparasitic helminths, with the infection being transferred to the definitive host fish after predation. Some digenean trematodes, especially species in the family Lepocreadiidae, use jellyfish as their second intermediate hosts. Fish become infected by the trematodes when they feed on infected jellyfish.

Relation to humans
Jellyfish have long been eaten in some parts of the world. Fisheries have begun harvesting the American cannonball jellyfish, Stomolophus meleagris, along the southern Atlantic coast of the United States and in the Gulf of Mexico for export to Asia.

Jellyfish are also harvested for their collagen, which is being investigated for use in a variety of applications including the treatment of rheumatoid arthritis.

Aquaculture and fisheries of other species often suffer severe losses – and so losses of productivity – due to jellyfish.

Products
Main article: Jellyfish as food
In some countries, including China, Japan, and Korea, jellyfish are a delicacy. The jellyfish is dried to prevent spoiling. Only some 12 species of scyphozoan jellyfish belonging to the order Rhizostomeae are harvested for food, mostly in southeast Asia. Rhizostomes, especially Rhopilema esculentum in China (海蜇 hǎizhé, 'sea stingers') and Stomolophus meleagris (cannonball jellyfish) in the United States, are favored because of their larger and more rigid bodies and because their toxins are harmless to humans.

Traditional processing methods, carried out by a jellyfish master, involve a 20- to 40-day multi-phase procedure in which, after removing the gonads and mucous membranes, the umbrella and oral arms are treated with a mixture of table salt and alum, and compressed. Processing makes the jellyfish drier and more acidic, producing a crisp texture. Jellyfish prepared this way retain 7–10% of their original weight, and the processed product consists of approximately 94% water and 6% protein. Freshly processed jellyfish has a white, creamy color and turns yellow or brown during prolonged storage.

In China, processed jellyfish are desalted by soaking in water overnight and eaten cooked or raw. The dish is often served shredded with a dressing of oil, soy sauce, vinegar and sugar, or as a salad with vegetables. In Japan, cured jellyfish are rinsed, cut into strips and served with vinegar as an appetizer. Desalted, ready-to-eat products are also available.

Biotechnology
The hydromedusa Aequorea victoria was the source of green fluorescent protein, studied for its role in bioluminescence and later for use as a marker in genetic engineering.
Pliny the Elder reported in his Natural History that the slime of the jellyfish "Pulmo marinus" produced light when rubbed on a walking stick.

In 1961, Osamu Shimomura extracted green fluorescent protein (GFP) and another bioluminescent protein, called aequorin, from the large and abundant hydromedusa Aequorea victoria, while studying photoproteins that cause bioluminescence in this species. Three decades later, Douglas Prasher sequenced and cloned the gene for GFP. Martin Chalfie figured out how to use GFP as a fluorescent marker of genes inserted into other cells or organisms. Roger Tsien later chemically manipulated GFP to produce other fluorescent colors to use as markers. In 2008, Shimomura, Chalfie and Tsien won the Nobel Prize in Chemistry for their work with GFP. Man-made GFP became widely used as a fluorescent tag to show which cells or tissues express specific genes. The genetic engineering technique fuses the gene of interest to the GFP gene. The fused DNA is then put into a cell, to generate either a cell line or (via IVF techniques) an entire animal bearing the gene. In the cell or animal, the artificial gene turns on in the same tissues and the same time as the normal gene, making a fusion of the normal protein with GFP attached to the end, illuminating the animal or cell reveals what tissues express that protein—or at what stage of development. The fluorescence shows where the gene is expressed.

Aquarium display
Jellyfish are displayed in many public aquariums. Often the tank's background is blue and the animals are illuminated by side light, increasing the contrast between the animal and the background. In natural conditions, many jellies are so transparent that they are nearly invisible. Jellyfish are not adapted to closed spaces. They depend on currents to transport them from place to place. Professional exhibits as in the Monterey Bay Aquarium feature precise water flows, typically in circular tanks to avoid trapping specimens in corners. The outflow is spread out over a large surface area and the inflow enters as a sheet of water in front of the outflow, so the jellyfish do not get sucked into it. As of 2009, jellyfish were becoming popular in home aquariums, where they require similar equipment.

Stings
Jellyfish are armed with nematocysts, a type of specialized stinging cell. Contact with a jellyfish tentacle can trigger millions of nematocysts to pierce the skin and inject venom, but only some species' venom causes an adverse reaction in humans. In a study published in Communications Biology, researchers found a jellyfish species called Cassiopea xamachana which when triggered will release tiny balls of cells that swim around the jellyfish stinging everything in their path. Researchers described these as "self-propelling microscopic grenades" and named them cassiosomes.

The effects of stings range from mild discomfort to extreme pain and death. Most jellyfish stings are not deadly, but stings of some box jellyfish (Irukandji jellyfish), such as the sea wasp, can be deadly. Stings may cause anaphylaxis (a form of shock), which can be fatal. Jellyfish kill 20 to 40 people a year in the Philippines alone. In 2006 the Spanish Red Cross treated 19,000 stung swimmers along the Costa Brava.

Vinegar (3–10% aqueous acetic acid) may help with box jellyfish stings but not the stings of the Portuguese man o' war. Clearing the area of jelly and tentacles reduces nematocyst firing. Scraping the affected skin, such as with the edge of a credit card, may remove remaining nematocysts. Once the skin has been cleaned of nematocysts, hydrocortisone cream applied locally reduces pain and inflammation. Antihistamines may help to control itching. Immunobased antivenins are used for serious box jellyfish stings.

In Elba Island and Corsica dittrichia viscosa is now used by residents and tourists to heal stings from jellyfish, bees and wasps pressing fresh leaves on the skin with quick results.

Mechanical issues
Jellyfish in large quantities can fill and split fishing nets and crush captured fish. They can clog cooling equipment, having disabled power stations in several countries; jellyfish caused a cascading blackout in the Philippines in 1999, as well as damaging the Diablo Canyon Power Plant in California in 2008. They can also stop desalination plants and ships' engines.

Asian Black Bear - Moon Bear - Asiatic Black Bear - White-Chested Bear (Ursus Thibetanus) by millicand@rocketmail.com

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Asian Black Bear - Moon Bear - Asiatic Black Bear - White-Chested Bear (Ursus Thibetanus)

The Asian black bear (Ursus thibetanus), also known as the Asiatic black bear, moon bear and white-chested bear, is a medium-sized bear species native to Asia that is largely adapted to an arboreal lifestyle. It lives in the Himalayas, southeastern Iran, the northern parts of the Indian subcontinent, the Korean Peninsula, China, the Russian Far East, the islands of Honshū and Shikoku in Japan, and Taiwan. It is listed as vulnerable on the IUCN Red List, and is threatened by deforestation and poaching for its body parts, which are used in traditional medicine.

Characteristics

The white V-shaped chest mark of an Asian black bear
The Asian black bear has black fur, a light brown muzzle, and a distinct whitish or creamy patch on the chest, which is sometimes V-shaped. Its ears are bell shaped, proportionately longer than those of other bears, and stick out sideways from the head. Its tail is short, around 11 cm (4.3 in) long. Adults measure 70–100 cm (28–39 in) at the shoulder, and 120–190 cm (47–75 in) in length. Adult males weigh 60–200 kg (130–440 lb) with an average weight of about 135 kg (298 lb). Adult females weigh 40–125 kg (88–276 lb), and large ones up to 140 kg (310 lb).

Asian black bears are similar in general build to brown bears (Ursus arctos), but are lighter and smaller. The lips and nose are larger and more mobile than those of brown bears. The skulls of Asian black bears are relatively small, but massive, particularly in the lower jaw. Adult males have skulls measuring 311.7 to 328 mm (12.27 to 12.91 in) in length and 199.5–228 mm (7.85–8.98 in) in width, while female skulls are 291.6–315 mm (11.48–12.40 in) long and 163–173 mm (6.4–6.8 in) wide. Compared to other bears of the genus Ursus, the projections of the skull are weakly developed; the sagittal crest is low and short, even in old specimens, and does not exceed more than 19–20% of the total length of the skull, unlike in brown bears, which have sagittal crests comprising up to 41% of the skull's length.

Although mostly herbivorous, the jaw structure of Asian black bears is not as specialized for plant eating as that of giant pandas: Asian black bears have much narrower zygomatic arches, and the weight ratio of the two pterygoid muscles is also much smaller in Asian black bears. The lateral slips of the temporal muscles are thicker and stronger in Asian black bears.

In contrast to polar bears, Asian black bears have powerful upper bodies for climbing trees, and relatively weak hind legs which are shorter than those in brown bears and American black bears. An Asian black bear with broken hind legs can still climb effectively. They are the most bipedal of all bears, and have been known to walk upright for over a quarter of a mile. The heel pads on the forefeet are larger than those of most other bear species. Their claws, which are primarily used for climbing and digging, are slightly longer on the fore foot (30–45 mm) than the back (18–36 mm), and are larger and more hooked than those of the American black bear.

On average, adult Asian black bears are slightly smaller than American black bears, though large males can exceed the size of several other bear species.

The famed British sportsman known as the "Old Shekarry" wrote of how an Asian black bear he shot in India probably weighed no less than 363 kg (800 lb) based on how many people it took to lift its body. The largest Asian black bear on record allegedly weighed 200 kg (440 lb). Zoo-kept specimens can weigh up to 225 kg (496 lb). Although their senses are more acute than those of brown bears, their eyesight is poor, and their hearing range is moderate, the upper limit being 30 kHz.

Taxonomy
Ancestral and sister taxa
Biologically and morphologically, Asian black bears represent the beginning of the arboreal specializations attained by sloth bears and sun bears. Asian black bears have karyotypes nearly identical to those of the five other ursine bears, and, as is typical in the genus, they have 74 chromosomes. From an evolutionary perspective, Asian black bears are the least changed of the Old World bears, with certain scientists arguing that it is likely that all other lineages of ursine bear stem from this species. Scientists have proposed that Asian black bears are either a surviving, albeit modified, form of Ursus etruscus, specifically the early, small variety of the Middle Villafranchian (Upper Pliocene to Lower Pleistocene) or a larger form of Ursus minimus, an extinct species that arose 4,000,000 years ago. With the exception of the age of the bones, it is often difficult to distinguish the remains of Ursus minimus with those of modern Asian black bears.

Asian black bears are close relatives to American black bears, with which they share a European common ancestor; the two species are thought to have diverged 3,000,000 years ago, though genetic evidence is inconclusive. Both the American and Asian black species are considered sister taxa and are more closely related to each other than to the other species of bear. The earliest known specimens of Asian black bears are known from the Early Pliocene of Moldova. The earliest American black bear fossils, which were located in Port Kennedy, Pennsylvania, greatly resemble the Asian black species. The first mtDNA study undertaken on Asian black bears suggested that the species arose after the American black bears, while a second study could not statistically resolve the branching order of sloth bears and the two black species, suggesting that these three species underwent a rapid radiation event. A third study suggested that American black bears and Asian black bears diverged as sister taxa after the sloth bear lineage and before the sun bear lineage. Further investigations on the entire mitochondrial cytochrome b sequence indicate that the divergence of continental Asian and Japanese black bear populations might have occurred when bears crossed the land bridge between the Korean peninsula and Japan 500,000 years ago, which is consistent with paleontological evidence.

Subspecies
Asian black bear subspecies
Subspecies nameCommon nameDistributionDescription
Ursus thibetanus formosanus R. Swinhoe, 1864
Formosan black bearTaiwanThis subspecies lacks the thick neck fur of other subspecies.
Ursus thibetanus gedrosianus Blanford, 1877
Balochistan black bearsouthern BalochistanA small subspecies with relatively short, coarse hair, often reddish-brown rather than black.
Ursus thibetanus japonicus Schlegel, 1857
Japanese black bearHonshū and Shikoku. Extinct on Kyushu.A small subspecies weighing 60–120 kg (130–260 lb) for the adult male and 40–100 kg (88–220 lb) for the adult female. The average body length is 1.1–1.4 m (3 ft 7 in – 4 ft 7 in). It lacks the thick neck fur of other subspecies, and has a darker snout.
Ursus thibetanus laniger Pocock, 1932
Himalayan black bearthe HimalayasDistinguished from U. t. thibetanus by its longer, thicker fur and smaller, whiter chest mark. During the summer, Himalayan black bears occur in warmer areas in Nepal, China, Siberia, and Tibet at elevations of 3,000–3,600 m (9,800–11,800 ft). For winter, they descend as low as 1,500 m (4,900 ft). On average, they measure 1.4–1.6 m (4 ft 7 in – 5 ft 3 in) from nose to tail and weigh from 90–120 kg (200–260 lb), though they may weigh as much as 181 kg (399 lb) in the fall when they are fattening up for hibernation.
Ursus thibetanus mupinensis Heude, 1901


indochinese black bearIndochinalight-colored, similar to U. t. laniger
Ursus thibetanus thibetanus Cuvier, 1823
Tibetan black bearAssam, Nepal, Myanmar, Mergui, Thailand and AnnamDistinguished from U. t. laniger by its short, thin coat with little to no underwool.
Ursus thibetanus ussuricus Heude, 1901


Ussuri black bearsouthern Siberia, northeastern China and the Korean peninsulathe largest subspecies
Until the Late Pleistocene, two further subspecies ranged across Europe and West Asia. These are U. t. mediterraneus from Western Europe and the Caucasus and U. t. permjak from Eastern Europe, particularly the Ural Mountains.

Hybrids
Asian black bears are reproductively compatible with several other bear species, and have on occasion produced hybrid offspring. According to Jack Hanna's Monkeys on the Interstate, a bear captured in Sanford, Florida, was thought to have been the offspring of an escaped female Asian black bear and a male American black bear, and Scherren's Some notes on hybrid bears published in 1907 mentioned a successful mating between an Asian black bear and a sloth bear. In 1975, within Venezuela's "Las Delicias" Zoo, a female Asian black bear shared its enclosure with a male spectacled bear, and produced several hybrid descendants. In 2005, a possible Asian black bear–sun bear hybrid cub was captured in the Mekong River watershed of eastern Cambodia. An Asian black bear/brown bear hybrid, taken from a bile farm, is housed at the Animals Asia Foundation's China Moon Bear Rescue as of 2010.

Distribution and habitat
Fossil record indicate that the Asian black bear once ranged as far west as Western Europe, though it now occurs very patchily throughout its former range, which is limited to Asia. Today, it occurs from southeastern Iran eastward through Afghanistan and Pakistan, across the foothills of the Himalayas in India and Myanmar to mainland Southeast Asia, except Malaysia. Its range in northeastern and southern China is patchy, and it is absent in much of east-central China. Other population clusters exist in the southern Russian Far East and in North Korea. A small remnant population survives in South Korea. It also occurs on the Japanese islands of Honshu and Shikoku, as well as on Taiwan and the Chinese island of Hainan.

It typically inhabits deciduous forests, mixed forests and thornbrush forests. In the summer, it usually inhabits altitudes of around 3,500 m (11,480 ft) in the Himalayas but rarely above 3,700 m (12,000 ft). In winter, it descends to altitudes below 1,500 m (4,920 ft). In Japan, it also occurs at sea level.

There is no definitive estimate as to the number of Asian black bears: Japan posed estimates of 8–14,000 bears living on Honshū, though the reliability of this is now doubted. Although their reliability is unclear, rangewide estimates of 5–6,000 bears have been presented by Russian biologists. In 2012, Japanese Ministry of the Environment estimated the population at 15–20,000. Rough density estimates without corroborating methodology or data have been made in India and Pakistan, resulting in the estimates of 7–9,000 in India and 1,000 in Pakistan. Unsubstantiated estimates from China give varying estimates between 15 and 46,000, with a government estimate of 28,000.

Bangladesh
The Wildlife Trust of Bangladesh conducted an on-field survey of bears in Bangladesh from 2008 to 2010 that included Asian black bears. The survey was done in 87 different places, mostly in the north-central, northeastern and southeastern areas of Bangladesh that had historical presence of bears. The survey result says that most of the areas still has some isolated small bear populations, mainly the Asian black bears. According to the survey, the most evidence found relating to bears were of Asian black bears that included nests, footprints, local sightings, etc. There are many reports on the presence of Asian black bears in the central, north-central, northeastern and southeastern parts of Bangladesh.

Although Asian black bears still occur in different parts of Bangladesh, mainly in the Chittagong Hill Tracts, the population is very small. Conservationists fear that the species will soon be extinct in the country if necessary steps to protect it are not taken in the near future.

China
Three subspecies of the Asian black bear occur in China: the Tibetan subspecies (U. thibetanus thibetanus), the Indochinese subspecies (U. thibetanus mupinensis), and the northeastern subspecies (U. thibetanus ussuricus), which is the only subspecies of bear in northeastern China. Asian black bears are mainly distributed in the conifer forests in the cold and temperate zones of northeast China, the main areas being Chang Bai, Zhang Guangcai, Lao Ye, and the Lesser Xingan Mountains. Within Liaoning province, there are about 100 Asian black bears, which only inhabit the five counties of Xin Bin, Huan Ren, Ben Xi, Kuan Dian, and Fen Cheng. Within Jilin province, Asian black bears occur mainly in the counties of Hunchun, Dun Hua, Wangqing, An Tu, Chang Bai, Fu Song, Jiao He, Hua Dian, Pan Shi, and Shu Lan. In Heilongjiang province, Asian black bears occur in the counties of Ning An, BaYan, Wu Chang, Tong He, Bao Qing, Fu Yuan, Yi Chun, Tao Shan, Lan Xi, Tie Li, Sun Wu, Ai Hui, De Du, Bei An, and Nen Jiang. This population has a northern boundary of about 50° N and the southern boundary in Feng Cheng is about 40°30" N.

Korea
In Korea, most of the Asian black bears live in the broad-leaved forest of the alpine region, more than 1,500 meters north of Jirisan. Korean National Park Service announced on April 15, 2018, that eight mother bears gave birth to 11 cubs. Six mother bears living in the wild gave birth to eight cubs. Two mothers that were being taken care by the nature adaptation training center in Gurye, South Jeolla Province gave birth to three cubs. Now, there are 56 Asian black bears living in the wild of Jirisan. If the Korea National Park Service releases three cubs born in natural adaptation training centers at September this year, the number of Asian black bears living in the wild will increase to 59. As a result, the restoration of the target of 50 Asian black bears, or the minimum remaining population, will be achieved two years earlier. It was a goal by 2020. Their next goal is to expand and improve the habitat and to increase the genetic diversity of the Asian black bears in Mt. Jiri.

Siberia
In Siberia, the Asian black bear's northern range runs from Innokenti Bay on the coast of the Sea of Japan southwest to the elevated areas of Sikhote Alin crossing it at the sources of the Samarga River. At this point, the boundary directs itself to the north, through the middle course of the Khor, Anyui and Khungari rivers, and comes to the shore of the Amur, crossing it at the level of the mouth of the Gorin River. Along the Amur river, the species' presence has been noted as far as 51° N. Lat. From there, the territorial boundary runs southwest of the river's left bank, passing through the northern part of Lake Bolon and the juncture point of the Kur and Tunguska. Asian black bears are encountered in the Urmi's lower course. Within the Ussuri krai, the species is restricted to broad-leaved Manchurian-type forests.

Taiwan
In Taiwan, the endemic subspecies of Asiatic Black Bear, the Formosan black bear (Ursus thibetanus formosanus), chiefly is confined to the mountain ranges in the central regions of the island. It can be found along the Central and Snow mountain ranges, with populations in the latter being more common. The largest population of bears seem to be Lala mountain in Chatienshan Reserve, the (Snow) Mountain area in Sheipa National Park, and Taroko National Park. These populations' individuals and numbers can be found south to Tawushan Reserve through Yushan National Park. Typically they are found in rugged areas at elevations of 1,000–3,500 metres (3,300–11,500 ft). The estimated number of individuals in these regions number some 200 to 600 bears.

Behavior and ecology

Asian black bears are diurnal, though they become nocturnal near human habitations. They will walk in a procession of largest to smallest. They are good climbers of rocks and trees, and will climb to feed, rest, sun, elude enemies and hibernate. Some older bears may become too heavy to climb. Half of their life is spent in trees and they are one of the largest arboreal mammals. In the Ussuri territory in the Russian Far East, Asian black bears can spend up to 15% of their time in trees. Asian black bears break branches and twigs to place under themselves when feeding on trees, thus causing many trees in their home ranges to have nest-like structures on their tops. Asian black bears will rest for short periods in nests on trees standing fifteen feet or higher.

Asian black bears do not hibernate over most of their range. They may hibernate in their colder, northern ranges, though some bears will simply move to lower elevations. Nearly all pregnant sows hibernate. Asian black bears prepare their dens for hibernation in mid-October, and will sleep from November until March. Their dens can either be dug-out hollow trees (60 feet above ground), caves or holes in the ground, hollow logs, or steep, mountainous and sunny slopes. They may also den in abandoned brown bear dens. Asian black bears tend to den at lower elevations and on less steep slopes than brown bears. Female Asian black bears emerge from dens later than do males, and female Asian black bears with cubs emerge later than barren females. Asian black bears tend to be less mobile than brown bears. With sufficient food, Asian black bears can remain in an area of roughly 1–2 km2 (0.39–0.77 sq mi), and sometimes even as little as 0.5–1 km2 (0.19–0.39 sq mi).

Asian black bears have a wide range of vocalizations, including grunts, whines, roars, slurping sounds (sometimes made when feeding) and "an appalling row" when wounded, alarmed or angry. They emit loud hisses when issuing warnings or threats, and scream when fighting. When approaching other bears, they produce "tut tut" sounds, thought to be produced by bears snapping their tongue against the roof of their mouth. When courting, they emit clucking sounds.

Reproduction and life cycle

Within Sikhote-Alin, the breeding season of Asian black bears occurs earlier than in brown bears, starting from mid-June to mid-August. Birth also occurs earlier, in mid-January. By October, the uterine horns of pregnant females grow to 15–22 mm (0.59–0.87 in). By late December, the embryos weigh 75 grams. Sows generally have their first litter at the age of three years. Pregnant females generally make up 14% of populations. Similar to brown bears, Asian black bears have delayed implantation. Sows usually give birth in caves or hollow trees in winter or early spring after a gestation period of 200–240 days. Cubs weigh 13 ounces at birth, and will begin walking at four days of age, and open their eyes three days later. The skulls of newborn Asian black bear cubs bear great resemblance to those of adult sun bears. Litters can consist of 1–4 cubs, with 2 being the average. Cubs have a slow growth rate, reaching only 2.5 kg by May. Asian black bear cubs will nurse for 104–130 weeks, and become independent at 24–36 months. There is usually a 2–3 year interval period before females produce subsequent litters. The average lifespan in the wild is 25 years, while the oldest Asian black bear in captivity died at the age of 44

Feeding

Asian black bears are omnivorous, and will feed on insects, beetle larvae, invertebrates, termites, grubs, carrion, bees, eggs, garbage, mushrooms, grasses, bark, roots, tubers, fruits, nuts, seeds, honey, herbs, acorns, cherries, dogwood, and grain. Although herbivorous to a greater degree than brown bears, and more carnivorous than American black bears, Asian black bears are not as specialized in their diet as giant pandas are: while giant pandas depend on a constant supply of low calorie, yet abundant foodstuffs, Asian black bears are more opportunistic and have opted for a nutritional boom-or-bust economy. They thus gorge themselves on a variety of seasonal high calorie foods, storing the excess calories as fat, and then hibernate during times of scarcity. Asian black bears will eat pine nuts and acorns of the previous year in the April–May period. In times of scarcity, they enter river valleys to gain access to hazelnuts and insect larvae in rotting logs. From mid-May through late June, they will supplement their diet with green vegetation and fruit. Through July to September, they will climb trees to eat bird cherries, pine cones, vines and grapes. On rare occasions they will eat dead fish during the spawning season, though this constitutes a much lesser portion of their diet than in brown bears. In the 1970s, Asian black bears were reported to kill and eat Hanuman langurs in Nepal. They appear to be more carnivorous than most other bears, including American black bears, and will kill ungulates with some regularity, including domestic livestock. Wild ungulate prey can include muntjacs, serow, takin, malayan tapir wild boar and adult water buffaloes, which they kill by breaking their necks.

Interspecific predatory relationships

The Asian black bear's range overlaps with that of the sloth bear in central and southern India, the sun bear in Southeast Asia and the brown bear in the southern part of the Russian Far East.

Asian black bears seem to intimidate Himalayan brown bears in direct encounters. They eat the fruit dropped by Asian black bears from trees, as they themselves are too large and cumbersome to climb.

Asian black bears are occasionally attacked by tigers and brown bears. Leopards are known to prey on bear cubs younger than two years old. Packs of wolves and Eurasian lynxes are potential predators of bear cubs as well. Asian black bears usually dominate Amur leopards in physical confrontations in heavily vegetated areas, while leopards are uppermost in open areas, though the outcome of such encounters is largely dependent on the size of the individual animals.

Ussuri brown bears may attack Asian black bears.

Tigers occasionally attack and consume Asian black bears. Russian hunters found their remains in tiger scats, and Asian black bear carcasses showing evidence of tiger predation. To escape tigers, Asian black bears rush up a tree and wait for the tiger to leave, though some tigers will pretend to leave, and wait for the bear to descend. Tigers prey foremost on young bears. Some are very tenacious when attacked: Jim Corbett observed a fight between a tiger and the largest Asian black bear he had ever seen. The bear managed to chase off the tiger, despite having half its nose and scalp torn off. He twice saw Asian black bears carry off tiger kills when the latter was absent. Asian black bears are usually safe from tiger attacks once they reach five years of age. One fatal attack of a tiger on a juvenile Asian black bear has been recorded in Jigme Dorji National Park. One Siberian tiger was reported to have lured an Asian black bear by imitating its mating call. However, Asian black bears are probably less vulnerable to tiger attacks than brown bears, due to their habit of living in hollows or in close set rocks.

Legal status
The Asian black bear is listed as a protected animal in China's National Protection Wildlife Law, which stipulates that anyone hunting or catching bears without permits will be subject to severe punishment.

Although the Asian black bear is protected in India, due to being listed as vulnerable in the Red Data Book in Appendix I of CITES in India and in Schedule I of the Indian Wildlife (Protection) Act and its 1991 amendment, it has been difficult to prosecute those accused of poaching Asian black bears due to lack of witnesses and lack of Wildlife Forensic Labs to detect the originality of confiscated animal parts or products. Moreover, due to India's wide-stretching boundaries with other nations such as Pakistan, Tibet, China, Nepal, Bhutan, Bangladesh and Myanmar, it is difficult to police such borders, which are often in mountainous terrain.

Five Asian black bear populations, occurring in Kyushu, Shikoku, West-Chugoku, East-Chugoku and Kii areas, were listed as endangered by the Environmental Agency in the Japanese Red Data Book in 1991. Small isolated populations in the Tanzawa and Shimokita areas of mainland Honshū were listed as endangered in 1995. Beyond recognizing these populations as endangered, there is still a lack of efficient conservation methods for Japanese black bears.

Asian black bears occur as an infrequent species in the Red Data Book of Russia, thus falling under special protection and hunting is prohibited. There is currently a strong movement to legalize the hunting of Russian black bears, which is supported by most of the local scientific community.

As of January 30, 1989, Taiwan's Formosan black bears have been listed as an endangered species under the Natural and Cultural Heritage Act on, and was later listed as a Conserved Species Category I.

The Vietnamese government issued Decision 276/QD, 276/1989, which prohibits the hunting and exporting of Asian black bears. The Red Book of Vietnam lists Vietnamese black bears as endangered.

The Korean Government designated the Asian black bear as Natural Monument No. 329 and it is considered an extinction crisis. At the present time, the Endangered Species Restoration Center of Korea National Park Service is going through species restoration business.

Threats

The main habitat threat to Asian black bears is overcutting of forests, mainly due to human populations increasing to over 430,000 in regions where bears are distributed, in the Shaanxi, Ganshu, and Sichuan provinces. 27 forestry enterprises were built in these areas between 1950 and 1985 (excluding the lumbering units belonging to the county). By the early 1990s, the Asian black bear distribution area was reduced to only one-fifth of the area that existed before the 1940s. Isolated bear populations face environmental and genetic stress in these circumstances. However, one of the most important reasons for their decrease involves overhunting, as Asian black bear paws, gall bladders and cubs have great economic value. Asian black bear harvests are maintained at a high level due to the harm they cause to crops, orchards and bee farms. During the 1950s and 1960s, 1,000 Asian black bears were harvested annually in the Heilongjiang Province. However, purchased furs were reduced by 4/5, even by 9/10 yearly in the late 1970s to the early 1980s. Asian black bears have also been declining annually in Dehong Dai and Jingpo Nations Autonomous Prefecture and the Yunnan Province.

Poaching for gall bladders and skin are the main threats faced by Asian black bears in India.

Although the poaching of Asian black bears is well known throughout Japan, authorities have done little to remedy the situation. The killing of nuisance bears is practiced year-round, and harvest numbers have been on the increase. Box traps have been widely used since 1970 to capture nuisance bears. It is estimated that the number of shot bears will decrease in time, due to the decline of old traditional hunters and the increase of a younger generation less inclined to hunt. Logging is also considered a threat.

Although Asian black bears have been afforded protection in Russia since 1983, illegal poaching, fueled by a growing demand for bear parts in the Asian market, is still a major threat to the Russian population. Many workers of Chinese and Korean origin, supposedly employed in the timber industry, are actually involved in the illegal trade. Some Russian sailors reportedly purchase bear parts from local hunters to sell them to Japanese and Southeast Asian clients. Russia's rapidly growing timber industry has been a serious threat to the Asian black bear's home range for three decades. The cutting of trees containing cavities deprives Asian black bears of their main source of dens, and forces them to den on the ground or in rocks, thus making them more vulnerable to tigers, brown bears and hunters.

In Taiwan, Asian black bears are not actively pursued, though steel traps set out for wild boars have been responsible for unintentional bear trappings. Timber harvesting has largely stopped being a major threat to Taiwan's Asian black bear population, though a new policy concerning the transfer of ownership of hill land from the government to private interests has the potential to affect some lowland habitat, particularly in the eastern part of the nation. The building of new cross island highways through bear habitat is also potentially threatening.

Vietnamese black bear populations have declined rapidly due to the pressures of human population growth and unstable settlement. Vietnamese forests have been shrinking: of the 87,000 km2 (34,000 sq mi) of natural forests, about 1,000 km2 (390 sq mi) disappear every year. Hunting pressures have also increased with a coinciding decline of environmental awareness.

South Korea remains one of two countries to allow bear bile farming to continue legally. As reported in 2009, approximately 1,374 Asian black bears reside in an estimated 74 bear farms, where they are kept for slaughter to fuel the demands of traditional Asian medicine. In sharp contrast, fewer than 20 Asian black bears can be found at Jirisan Restoration Center, located in Korea's Jirisan National Park.

Relationships with humans

In Japanese culture, the Asian black bear is traditionally associated with the mountain spirit (yama no kami) and is characterized variously as "mountain man" (yamaotoko), "mountain uncle" (yama no ossan), "mountain father" (yama no oyaji), a loving mother, and a child. Being a largely solitary creature, the Asian black bear is also viewed as "lonely person" (sabishigariya). Asian black bears feature very little in lowland Japanese folklore, but are prominent in upland Japan, a fact thought to reflect the bear's greater economic value in upland areas. According to the local folklore in Kituarahara-gun in Niigata, the Asian black bear received its white mark after being given a silk-wrapped amulet by yama no kami, which left the mark after being removed. In Hindu mythology, the Asian black bear Jambavantha (also known as Jambavan or Jamvanta) is believed to have lived from Treta Yuga to Dvapara Yuga. In the epic Ramayana, Jambavantha assists Rama in finding his wife Sita and battle her abductor, Ravana.

Asian black bears are briefly mentioned in Yann Martel's novel The Life of Pi, in which they are described by the protagonist's father as being among the most dangerous animals in his zoo.

Although usually shy and cautious animals, Asian black bears are more aggressive towards humans than the brown bears of Eurasia and American black bears. David W. Macdonald theorizes that this greater aggression is an adaptation to being sympatric with tigers. According to Brigadier General R. G. Burton:

The Himalayan black bear is a savage animal, sometimes attacking without provocation, and inflicting horrible wounds, attacking generally the head and face with their claws, while using their teeth also on a prostrate victim. It is not uncommon to see men who have been terribly mutilated, some having the scalp torn from the head, and many sportsmen have been killed by these bears.

— A Book of Man Eaters, Chapter XVII Bears
In response to a chapter on Asian black bears written by Robert Armitage Sterndale in his Natural History of the Mammalia of India and Ceylon on how Asian black bears were no more dangerous than other animals in India, a reader responded with a letter to The Asian on May 11, 1880:

Mr Sterndale, in the course of his interesting papers on the Mammalia of British India, remarks of Ursus Tibetanus, commonly known as the Himalayan Black Bear, that 'a wounded one will sometimes show fight, but in general it tries to escape.' This description is not, I think, quite correct. As it would lead one to suppose that this bear is not more savage than any other wild animal—the nature of most of the feræ being to try to escape when wounded, unless they see the hunter who has fired at them, when many will charge at once, and desperately. The Himalayan Black Bear will not only do this almost invariably, but often attacks men without any provocation whatever, and is altogether about the most fierce, vicious, dangerous brute to be met with either in the hills or plains of India. [...] These brutes are totally different in their dispositions to the Brown Bear (Ursus Isabellinus), which, however desperately wounded, will never charge. I believe there is no case on record of a hunter being charged by a Brown Bear; or even of natives, under any circumstances, being attacked by one; whereas every one of your readers who has ever marched in the Himalayas must have come across many victims of the ferocity of Ursus Tibetanus.

At the turn of the 20th century, a hospital in Srinagar, Kashmir received dozens of Asian black bear victims annually. When Asian black bears attack humans, they rear up on their hind legs and knock victims over with their front paws. Then they bite them on an arm or leg and snap on the victim's head, this being the most dangerous part of the attack. Asian black bear attacks have been increasing in Kashmir since the Kashmir conflict. In November 2009, in the Kulgam district of Indian-administered Kashmir, an Asian black bear attacked four insurgents after discovering them in its den, and killed two of them.

In India, attacks on humans have been increasing yearly, and have occurred largely in the northwestern and western Himalayan region. In the Chamba District of Himachal Pradesh, the number of Asian black bear attacks on humans has gradually increased from 10 in 1988–89 to 21 in 1991–92. There are no records of predation on humans by Asian black bears in Russia, and no conflicts have been documented in Taiwan. Recent Asian black bear attacks on humans have been reported from Junbesi in Langtang National Park, Nepal, and occurred in villages as well as in the surrounding forest.

Nine people were killed by Asian black bears in Japan between 1979 and 1989. In September 2009, an Asian black bear attacked a group of tourists, mauling nine people and seriously injuring four more at a bus station in the built-up area of Takayama, Gifu. The majority of attacks tend to occur when Asian black bears are encountered suddenly, and in close quarters. Because of this, Asian black bears are generally considered more dangerous than brown bears, which live in more open spaces and are thus less likely to be surprised by approaching humans. They are also likely to attack when protecting food.

2016 saw several attacks by Asian black bears in Japan. In May and June four people were killed by Asian black bears in Akita prefecture while picking bamboo shoots, and in August a female safari park worker in Gunma prefecture was killed when an Asian black bear climbed into her car and attacked her.

Livestock predation and crop damage
In the past, the farmers of the Himalayan lowlands feared Asian black bears more than any other pest, and would erect platforms in the fields, where watchmen would be posted at night and would beat drums to frighten off any interlopers. However, some Asian black bears would grow accustomed to the sound and encroach anyway.

Of 1,375 livestock kills examined in Bhutan, Asian black bears accounted for 8% of attacks. Livestock predation, overall, was greatest in the summer and autumn periods, which corresponded with a peak in cropping agriculture; livestock are turned out to pasture and forest during the cropping season and, subsequently, are less well-guarded than at other times.

Livestock killed by Asian black bears in Himachal Pradesh, India increased from 29 in 1988–1989 to 45 in 1992–1993.

In the remoter areas of Japan, Asian black bears can be serious crop predators: the bears feed on cultivated bamboo shoots in spring, on plums, watermelons and corn in the summer, and on persimmons, sweet potatoes and rice in the autumn. Japanese black bears are estimated to damage 3,000 bee hives annually. When feeding on large crops such as watermelons or pumpkins, Asian black bears will ignore the flesh and eat the seeds, thus adversely affecting future harvests. Asian black bears can girdle and kill trees by stripping their bark for the sap. This can cause serious economic problems in Asia's valuable timber forests. In the late 1970s, 400–1,200 hectares of land had been affected by Asian black bears bark-stripping Japanese conifers. There is evidence that 70-year-old conifers (commanding the highest market values) may also have been bark-stripped.

Asian black bears will prey on livestock if their natural food is in poor supply. They have been known to attack bullocks, either killing them outright, or eating them alive.

Tameability and trainability
Along with sun bears, Asian black bears are the most typically used species in areas where bears are used either in performances or as pets. Asian black bears have an outstanding learning ability in captivity, and are among the most common species used in circus acts. According to Gary Brown:

The Asiatic black bears are the comedians of the performing bears. They appear to appreciate applause and will intentionally move into their prescribed position late to attain laughter and attention. — Brown, The Influence of Bears on Humans

Asian black bears are easily tamed, and can be fed with rice, maize, sweet potatoes, cassavas, pumpkins, ripe fruit, animal fat and sweet foods. Keeping captive Asian black bears is popular in China, especially due to the belief that milking the bear's gall bladder leads to quick prosperity. Asian black bears are also popular as pets in Vietnam.

Hunting
An Asian black bear hunt, as illustrated by Samuel Howitt
According to The Great and Small Game of India, Burma, and Tibet, regarding the hunting of Asian black bears in British India:

Black bear stalking in the forests bordering the valley of Kashmir requires much more care than is expended in approaching brown bear on the open hills above, the senses of sight and hearing being more strongly developed in the black than in the brown species. Many of these forests are very dense, so that it requires the eye of an experienced shikari [hunter] to detect the dark forms of the bears while searching for chestnuts on the ground without the advancing party being detected by the vigilant animals.

— The Great and Small Game of India, Burma, and Tibet p. 367

The book also describes a second method of black bear hunting involving the beating of small patches of forest, when the bears march out in single file. However, black bears were rarely hunted for sport, because of the poor quality of their fur and the ease by which they could be shot in trees, or stalked, as their hearing was poor.

Black bears here afford no sport; it is not shooting at all, it is merely potting a black thing in a tree... I can assure the reader that if he has a fondness for stalking, he will despise bear-killing, and will never shoot at them if there is a chance of anything else. If a man were to hunt for nothing else but bears, and kill a hundred in his six months' leave, he would not have enjoyed such real sport as he would, had he killed ten buck ibex or markhoor.

Although easy to track and shoot, Asian black bears were known by British sportsmen to be extremely dangerous when injured. Brigadier General R.G. Burton wrote of how many sportsmen had been killed by Asian black bears after failing to make direct hits.

Today, Asian black bears are only legally hunted for sport in Japan and Russia. In Russia, 75–100 Asian black bears are legally harvested annually, though 500 a year are reportedly harvested illegally.

After the introduction of Buddhism in Japan, which prohibited the killing of animals, the Japanese compromised by devising different strategies in hunting bears. Some, such as the inhabitants of the Kiso area in the Nagano Prefecture, prohibited the practice altogether, while others developed rituals in order to placate the spirits of killed bears. In some Japanese hunting communities, Asian black bears lacking the white chest mark are considered sacred. In the Akita Prefecture, bears lacking the mark were known by matagi huntsmen as minaguro (all-black) or munaguro (black-chested), and were also considered messengers of yama no kami. If such a bear was shot, the huntsman would offer it to yama no kami, and give up hunting from that time on. Similar beliefs were held in Nagano, where the completely black Asian black bears were termed nekoguma or cat-bear. Matagi communities believed that killing an Asian black bear in the mountains would result in a bad storm, which was linked to the belief that bear spirits could affect weather. The matagi would generally hunt Asian black bears in spring or from late autumn to early winter, before they hibernated. In mountain regions, Asian black bears were hunted by driving them upland to a waiting hunter, who would then shoot it. Bear hunting expeditions were preceded by rituals, and could last up to two weeks. After killing the bear, the matagi would pray for the bear's soul. Asian black bear hunts in Japan are often termed kuma taiji, meaning "bear conquest". The word taiji itself is often used in Japanese folklore to describe the slaying of monsters and demons.

Traditionally, the Atayal, Taroko, and Bunun people of Taiwan consider Asian black bears to be almost human in their behaviors, and thus unjust killing of bears is equated with murder and will cause misfortunes such as disease, death, or crop failure. The Bunun people call Asian black bears Aguman or Duman, which means devil. Traditionally, a Bunun hunter who has accidentally trapped an Asian black bear has to build a cottage in the mountains and cremate the bear within it. The hunter must stay in the cottage alone, away from the village until the end of the millet harvest, as it is believed that the killing of an Asian black bear will cause the millet crop to burn black. In the Tungpu area, Asian black bears are considered animals of the "third category": animals with the most remote relationship to humans and whose activity is restricted outside human settlements. Therefore, when Asian black bears encroach upon human settlements, they are considered ill omens. In this situation, the community can either destroy the trespassing bears or settle somewhere else. The Rukai and Paiwan people are permitted to hunt Asian black bears, though they believe that doing so will curse the hunters involved: Rukai people believe that hunting Asian black bears can result in disease. Children are forbidden from eating bear meat, which is itself not permitted to be taken within homes.

Products
Asian black bears have been hunted for their body parts in China since the Stone Age. In the 19th century, its fur was considered of low value. Grease was the only practical use for their carcasses in British India, and bears living near villages were considered ideal, as they were almost invariably fatter than forest-dwelling ones. In the former USSR, the Asian black bear yielded fur, meat and fat of greater quality than those of the brown bear. Today, bile is in demand, as it supposedly cures various diseases, treats the accumulation of blood below the skin, and counters toxic effects. Products also include bone 'glue' and fat, both used in traditional medicine and consumed as a tonic. Asian black bear meat is also edible.

Capybara - Greater Capybara (Hydrochoerus Hydrochaeris) by millicand@rocketmail.com

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Capybara - Greater Capybara (Hydrochoerus Hydrochaeris)

The capybara or greater capybara (Hydrochoerus hydrochaeris) is a giant cavy rodent native to South America. It is the largest living rodent and a member of the genus Hydrochoerus. The only other extant member is the lesser capybara (Hydrochoerus isthmius). Its close relatives include guinea pigs and rock cavies, and it is more distantly related to the agouti, the chinchilla, and the nutria. The capybara inhabits savannas and dense forests, and lives near bodies of water. It is a highly social species and can be found in groups as large as 100 individuals, but usually live in groups of 10–20 individuals. The capybara is hunted for its meat and hide and also for grease from its thick fatty skin.

Etymology
Its common name is derived from Tupi ka'apiûara, a complex agglutination of kaá (leaf) + píi (slender) + ú (eat) + ara (a suffix for agent nouns), meaning "one who eats slender leaves", or "grass-eater". The scientific name, both hydrochoerus and hydrochaeris, comes from Greek ὕδωρ (hydor "water") and χοῖρος (choiros "pig, hog").

Classification and phylogeny
The capybara and the lesser capybara both belong to the subfamily Hydrochoerinae along with the rock cavies. The living capybaras and their extinct relatives were previously classified in their own family Hydrochoeridae. Since 2002, molecular phylogenetic studies have recognized a close relationship between Hydrochoerus and Kerodon, the rock cavies, supporting placement of both genera in a subfamily of Caviidae.

Paleontological classifications previously used Hydrochoeridae for all capybaras, while using Hydrochoerinae for the living genus and its closest fossil relatives, such as Neochoerus, but more recently have adopted the classification of Hydrochoerinae within Caviidae.[11] The taxonomy of fossil hydrochoerines is also in a state of flux. In recent years, the diversity of fossil hydrochoerines has been substantially reduced. This is largely due to the recognition that capybara molar teeth show strong variation in shape over the life of an individual. In one instance, material once referred to four genera and seven species on the basis of differences in molar shape is now thought to represent differently aged individuals of a single species, Cardiatherium paranense. Among fossil species, the name "capybara" can refer to the many species of Hydrochoerinae that are more closely related to the modern Hydrochoerus than to the "cardiomyine" rodents like Cardiomys. The fossil genera Cardiatherium, Phugatherium, Hydrochoeropsis, and Neochoerus are all capybaras under that concept.

Description
The capybara has a heavy, barrel-shaped body and short head, with reddish-brown fur on the upper part of its body that turns yellowish-brown underneath. Its sweat glands can be found in the surface of the hairy portions of its skin, an unusual trait among rodents. The animal lacks down hair, and its guard hair differs little from over hair.

Adult capybaras grow to 106 to 134 cm (3.48 to 4.40 ft) in length, stand 50 to 62 cm (20 to 24 in) tall at the withers, and typically weigh 35 to 66 kg (77 to 146 lb), with an average in the Venezuelan llanos of 48.9 kg (108 lb). Females are slightly heavier than males. The top recorded weights are 91 kg (201 lb) for a wild female from Brazil and 73.5 kg (162 lb) for a wild male from Uruguay. Also, an 81 kg individual was reported in São Paulo in 2001 or 2002. The dental formula is
1.0.1.3
1.0.1.3
Capybaras have slightly webbed feet and vestigial tails. Their hind legs are slightly longer than their forelegs; they have three toes on their rear feet and four toes on their front feet. Their muzzles are blunt, with nostrils, and the eyes and ears are near the top of their heads.

Its karyotype has 2n = 66 and FN = 102, meaning it has 66 chromosomes with a total of 102 arms.

Ecology
Capybaras are semiaquatic mammals found throughout all countries of South America except Chile. They live in densely forested areas near bodies of water, such as lakes, rivers, swamps, ponds, and marshes, as well as flooded savannah and along rivers in the tropical rainforest. They are superb swimmers and can hold their breath underwater for up to five minutes at a time. Capybara have flourished in cattle ranches. They roam in home ranges averaging 10 hectares (25 acres) in high-density populations.

Many escapees from captivity can also be found in similar watery habitats around the world. Sightings are fairly common in Florida, although a breeding population has not yet been confirmed. In 2011, one specimen was spotted on the Central Coast of California. These escaped populations occur in areas where prehistoric capybaras inhabited; late Pleistocene capybaras inhabited Florida and Hydrochoerus hesperotiganites in California and Hydrochoerus gaylordi in Grenada, and feral capybaras in North America may actually fill the ecological niche of the Pleistocene species.

Diet and predation
Capybaras are herbivores, grazing mainly on grasses and aquatic plants, as well as fruit and tree bark. They are very selective feeders and feed on the leaves of one species and disregard other species surrounding it. They eat a greater variety of plants during the dry season, as fewer plants are available. While they eat grass during the wet season, they have to switch to more abundant reeds during the dry season. Plants that capybaras eat during the summer lose their nutritional value in the winter, so they are not consumed at that time. The capybara's jaw hinge is not perpendicular, so they chew food by grinding back-and-forth rather than side-to-side. Capybaras are autocoprophagous, meaning they eat their own feces as a source of bacterial gut flora, to help digest the cellulose in the grass that forms their normal diet, and to extract the maximum protein and vitamins from their food. They also regurgitate food to masticate again, similar to cud-chewing by cattle. As is the case with other rodents, the front teeth of capybaras grow continually to compensate for the constant wear from eating grasses; their cheek teeth also grow continuously.

Like its relative the guinea pig, the capybara does not have the capacity to synthesize vitamin C, and capybaras not supplemented with vitamin C in captivity have been reported to develop gum disease as a sign of scurvy.

They can have a lifespan of 8–10 years, but tend to live less than four years in the wild due to predation from big cats like the jaguars and pumas and non-mammalian predators like eagles and the caimans. The capybara is also the preferred prey of the green anaconda.

Social organization
Capybaras are known to be gregarious. While they sometimes live solitarily, they are more commonly found in groups of around 10–20 individuals, with two to four adult males, four to seven adult females, and the remainder juveniles. Capybara groups can consist of as many as 50 or 100 individuals during the dry season when the animals gather around available water sources. Males establish social bonds, dominance, or general group consensus. They can make dog-like barks when threatened or when females are herding young.

Capybaras have two types of scent glands: a morrillo, located on the snout, and anal glands. Both sexes have these glands, but males have much larger morrillos and use their anal glands more frequently. The anal glands of males are also lined with detachable hairs. A crystalline form of scent secretion is coated on these hairs and is released when in contact with objects such as plants. These hairs have a longer-lasting scent mark and are tasted by other capybaras. Capybaras scent-mark by rubbing their morrillos on objects, or by walking over scrub and marking it with their anal glands. Capybaras can spread their scent further by urinating; however, females usually mark without urinating and scent-mark less frequently than males overall. Females mark more often during the wet season when they are in estrus. In addition to objects, males also scent-mark females.

Reproduction
When in estrus, the female's scent changes subtly and nearby males begin pursuit. In addition, a female alerts males she is in estrus by whistling through her nose. During mating, the female has the advantage and mating choice. Capybaras mate only in water, and if a female does not want to mate with a certain male, she either submerges or leaves the water. Dominant males are highly protective of the females, but they usually cannot prevent some of the subordinates from copulating. The larger the group, the harder it is for the male to watch all the females. Dominant males secure significantly more matings than each subordinate, but subordinate males, as a class, are responsible for more matings than each dominant male. The lifespan of the capybara's sperm is longer than that of other rodents.

Capybara gestation is 130–150 days, and produces a litter of four young on average, but may produce between one and eight in a single litter. Birth is on land and the female rejoins the group within a few hours of delivering the newborn capybaras, which join the group as soon as they are mobile. Within a week, the young can eat grass, but continue to suckle—from any female in the group—until weaned around 16 weeks. The young form a group within the main group. Alloparenting has been observed in this species. Breeding peaks between April and May in Venezuela and between October and November in Mato Grosso, Brazil.

Activities
Though quite agile on land, capybaras are equally at home in the water. They are excellent swimmers, and can remain completely submerged for up to five minutes, an ability they use to evade predators. Capybaras can sleep in water, keeping only their noses out. As temperatures increase during the day, they wallow in water and then graze during the late afternoon and early evening. They also spend time wallowing in mud. They rest around midnight and then continue to graze before dawn.

Conservation and human interaction
Capybaras are not considered a threatened species; their population is stable throughout most of their South American range, though in some areas hunting has reduced their numbers. Capybaras are hunted for their meat and pelts in some areas, and otherwise killed by humans who see their grazing as competition for livestock. In some areas, they are farmed, which has the effect of ensuring the wetland habitats are protected. Their survival is aided by their ability to breed rapidly.

Capybaras have adapted well to urbanization in South America. They can be found in many areas in zoos and parks, and may live for 12 years in captivity, more than double their wild lifespan. Capybaras are docile and usually allow humans to pet and hand-feed them, but physical contact is normally discouraged, as their ticks can be vectors to Rocky Mountain spotted fever. The European Association of Zoos and Aquaria asked Drusillas Park in Alfriston, Sussex, England, to keep the studbook for capybaras, to monitor captive populations in Europe. The studbook includes information about all births, deaths and movements of capybaras, as well as how they are related.

Capybaras are farmed for meat and skins in South America. The meat is considered unsuitable to eat in some areas, while in other areas it is considered an important source of protein. In parts of South America, especially in Venezuela, capybara meat is popular during Lent and Holy Week as the Catholic Church previously issued special dispensation to allow it to be eaten while other meats are generally forbidden. After several attempts a 1784 Papal bull was obtained that allowed the consumption of capybara during Lent. There is widespread perception in Venezuela that consumption of capybaras is exclusive to rural people.

Although it is illegal in some states, capybaras are occasionally kept as pets in the United States. The image of a capybara features on the 2-peso coin of Uruguay. In Japan, following the lead of Izu Shaboten Zoo in 1982, multiple establishments or zoos in Japan that raise capybaras have adopted the practice of having them relax in onsen during the winter. They are seen as an attraction by Japanese people. Capybaras became big in Japan due to the popular cartoon character Kapibara-san.

In August 2021, Argentine and international media reported that capybaras had been causing serious problems for residents of Nordelta, an affluent gated community north of Buenos Aires built atop wetland habitat. This inspired social media users to jokingly adopt the capybara as a symbol of class struggle and communism. Brazilian Lyme-like borreliosis likely involves capybaras as reservoirs and Amblyomma and Rhipicephalus ticks as vectors.

Popularity and meme culture
In the early 2020s, capybaras became a growing figure of meme culture due to many factors, including the disturbances in Nordelta which led to them being comically postulated as figures of class struggle. Also, a common meme format includes capybaras in various situations with the song "After Party" by Don Toliver, leading to a tremendous growth in popularity. Capybaras also associated with the phrase "Ok I pull up", the opening lyric in Toliver’s song

Desert Cockroach - Seven-Spotted Cockroach - Indian Domino Cockroach (Therea Petiveriana) by millicand@rocketmail.com

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Desert Cockroach - Seven-Spotted Cockroach - Indian Domino Cockroach (Therea Petiveriana)

Therea petiveriana, variously called the desert cockroach, seven-spotted cockroach, or Indian domino cockroach, is a species of crepuscular cockroach found in southern India. They are members of a basal group within the cockroaches. This somewhat roundish and contrastingly marked cockroach is mainly found on the ground in scrub forest habitats where they may burrow under leaf litter or loose soil during the heat of the day.

Description
The black and white pattern of adults is believed to have evolved to mimic the pattern of the aggressive ground beetle Anthia sexguttata that has strong defenses, including the ability to spray chemical irritants. The upperside of the abdomen is orange-yellow, but is hidden by the tegmina. The spots on the asymmetrical tegmina are placed so that when closed, the spots appear symmetrical. The right tegmen lobe is bright orange-yellow. The species has been said to be one of the few cockroaches with "grace and beauty". The head is bent back underneath the pronotal shield (hypognathous) and the ocelli (simple eyes) face forward, helping sense light and thereby time, and they forage actively during early morning and late evening.

Reproduction
Once a female has copulated with a male, she does not allow other males to approach, kicking them away with her hind legs. The eggs are laid in leaf litter. Up to 13 oothecae are produced by a female over 3 to 40 days (blocking the ocelli of the females has been found to inhibit the laying of eggs). The oothecae are produced as in other cockroaches by the secretions from the asymmetrical colleterial glands of the females. Once the ootheca is extruded it is deposited in suitably moist leaf litter. Nymphs lead a life hidden below the ground and may go as deep as 30 cm during the dry season.

Taxonomy
This is the type species for the genus Therea. The species epithet is after James Petiver (1663–1718), who obtained specimens from Madras and its vicinity (probably from the surgeon at Fort St. George, either Samuel Browne or more likely Edward Bulkley). Carl Linnaeus placed the species under Cassida and described C. petiveriana and another that he called C. septemguttata, now considered a synonym.

Communication
Like other cockroaches, T. petiveriana uses chemical pheromones to communicate with each other. When disturbed, they are said to raise their wings and evert lateral glands on the second and third abdominal segments. Their glandular secretions were found to contain volatile compounds N-3-methylbutylacetamide (MBA) and N-3-methylbutylpropanamide (MBP), making up nearly 60% of the volatile fraction. These chemicals appeared to induce alarm behaviour.

Digestion
Like termites, these cockroaches have symbiotic flagellates and bacteria in their gut that aid in digestion.

As pets
The conspicuously marked Therea cockroaches are popular as pets and easy to keep. The most commonly kept species has often been identified as T. petiveriana, but in 2009 it was instead suggested that the captive population actually belongs to a separate species, T. bernhardti, that differs primarily in the hindwings (which usually are hidden behind the tegmina), but also in small details of the tegmina pattern.

Mantis (Mantodea) by millicand@rocketmail.com

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Mantis (Mantodea)

Mantises, belonging to the order Mantodea, are fascinating insects with a rich evolutionary history that spans millions of years.

The origin of mantises can be traced back to the early Cretaceous period, approximately 145 to 100 million years ago. Fossil evidence suggests that their ancestors were similar to cockroaches, with elongated bodies and chewing mouthparts. Over time, these ancestral insects underwent various adaptations that led to the emergence of the distinct features we associate with mantises today.

One of the defining characteristics of mantises is their forelegs modified for capturing and grasping prey. This adaptation evolved gradually, with ancestral species developing elongated legs to improve their hunting abilities. As mantises continued to evolve, their front legs became highly specialized, featuring sharp spines and powerful grasping capabilities.

Throughout their evolutionary history, mantises diversified into numerous species, each adapting to different environments and ecological niches. Today, there are over 2,400 known species of mantises, exhibiting a remarkable range of sizes, shapes, and colors.

Mantises are distributed worldwide, inhabiting diverse habitats, including tropical rainforests, temperate regions, and deserts. They are particularly abundant in regions with warm climates and abundant vegetation, as these conditions provide ample prey opportunities.

Behaviorally, mantises are known for their unique hunting strategies and impressive camouflage. Many species exhibit aggressive mimicry, resembling flowers, leaves, or twigs to blend seamlessly into their surroundings, making them highly effective ambush predators. This camouflage allows mantises to remain inconspicuous while waiting for unsuspecting prey to venture within striking range.

The reproductive behavior of mantises is equally intriguing. Sexual cannibalism, where the female consumes the male after or during mating, is a well-known phenomenon observed in some mantis species. While not all species exhibit this behavior, it has been hypothesized that it may provide nutritional benefits to the female or serve as a form of male sacrifice to increase the chances of successful reproduction.

Mantises undergo incomplete metamorphosis, a type of development that involves three life stages: egg, nymph, and adult. Females typically lay their eggs within protective foam masses called oothecae, which are attached to twigs, stems, or other structures. These oothecae safeguard the developing eggs from predators and environmental hazards until they hatch into nymphs.

Nymphs resemble miniature adults but lack wings and are less sexually mature. They go through a series of molts, shedding their exoskeletons to accommodate growth. With each molt, nymphs become increasingly similar to the adult form, eventually reaching full maturity.

While mantises have existed for millions of years, they face various challenges and threats today. Habitat destruction, pesticide use, and climate change contribute to the decline of mantis populations in certain areas. Conservation efforts are crucial to preserving their diversity and ecological importance.

In conclusion, mantises have a long and fascinating evolutionary history that has shaped them into the unique insects we know today. From their cockroach-like ancestors to the specialized hunters and masters of camouflage we see in various species, mantises have successfully adapted to a range of environments worldwide. Their behavioral and reproductive strategies, combined with their remarkable diversity, continue to captivate scientists and nature enthusiasts alike. By appreciating and conserving these intriguing insects, we can ensure their continued survival and contribute to the preservation of Earth's biodiversity.

Burying Beetle (Nicrophorus Vespilloides) by millicand@rocketmail.com

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Burying Beetle (Nicrophorus Vespilloides)

Nicrophorus vespilloides is a burying beetle described by Johann Friedrich Wilhelm Herbst in 1783.

The beetles are 10 – 18 mm long. They have two conspicuous orange-yellow bands on the elytra. The color of the antennae are an important distinguishing feature, being totally black.

This is one of the most well studied of the burying beetles with over 1,000 citations found via Google Scholar. What had been considered Nicrophorus vespilloides in mid and eastern Canada and northeastern USA was determined by Sikes et al. in 2016 to be a separate, overlooked sister species of Nicrophorus vespilloides that had been named by Kirby in 1837.

This sister species, Nicrophorus hebes Kirby, is restricted to Sphagnum bogs and marshes,. Nicrophorus vespilloides occurs throughout the northern Palearctic, Alaska and northwestern Canada where it is found in open forest habitats. The restriction of its sister species N. hebes to bogs in North America has been attributed to competition with its closely related congener, N. defodiens which in this area is found in forest habitats. N. hebes reproduces exclusively in bogs in North America and is never found in adjacent (<100 m or 330 ft) forested habitat in the Mer Bleue bog area near Ottawa, Ontario, Canada.

There are also a number of phoretic (hitch-hiking) mites that are associated with N. vespilloides. These include Pelzneria nr. crenulata, Macrocheles merderius, and Uroobovella nr. novasimilis and the largest mite Poecilochirus carabi. P. carabi is not attached by any physical means (such as a secreted anal stalk in the case of M. merderius) to N. vespilloides. When the males or females of N. vespilloides have finished breeding on a carcass the deutonymphs of P. carabi roam freely about the body of the beetles as they search for new carcasses to reproduce. It had been proposed that P. carabi deutonymphs, on arrival at a new carcass dismounted from the beetles and consumed fly eggs and larvae which would have competed for the beetle larvae for food. This relationship which benefited the beetles has been described as mutualistic. However, it has been shown that adults of P. carabi consume the eggs of N. vespilloides and that this has direct and negative effects on the reproduction of this beetle species.

N. vespilloides is also used as a model organism in the study of social immunity.