Cheetah

The Cheetah (Acinonyx jubatus) is a vulnerable member of the cat family (Felidae), a poor climber that hunts by speed and stealth. As such, it is placed in its own genus, Acinonyx. It is the fastest of all land animals and can reach speeds of up to 105 kilometres per hour (65 mph) in short bursts up to 460 meters (500 yards), and has the ability to accelerate from 0 to 110 kilometers per hour (70 mph) in three seconds, faster than most super cars.

The word "cheetah" is derived from the Sanskrit word chitrakāyaḥ चित्रकायः meaning "variegated body", via the Hindi cītā चीता.

The Cheetah has a slender, long-legged body with blunt semi-retractable claws. Its chest is deep and its waist is narrow. The coarse, short fur of the Cheetah is tan with round black spots measuring from 2-3 centimeters (¾ to 1¼ inches) across, affording it some camouflage while hunting. There are no spots on its white underside, but the tail has spots, which merge to form four to six dark rings at the end. The tail usually ends in a bushy white tuft. The Cheetah has a small head with high-set eyes. Black "tear marks" run from the corner of its eyes down the sides of the nose to its mouth to keep sunlight out of its eyes and to aid in hunting and seeing long distances.

The adult animal weighs from 40 to 65 kilograms (90 to 140 lb). Its total body length is from 115 to 135 centimeters (45 in to 55 in), while the tail can measure up to 84 centimeters (33 in) in length. Males tend to be slightly larger than females and have slightly bigger heads, but there is great variation in Cheetah sizes and it is difficult to tell males and females apart by appearance alone. Compared to a similarly-sized Leopard, the Cheetah is generally shorter-bodied, but is longer tailed and taller (it averages about 90 cm or 36 in tall) and so it appears more streamlined.

Some Cheetahs also have a rare fur pattern mutation: Cheetahs with larger, blotchy, merged spots are known as 'king Cheetahs'. It was once thought to be a separate subspecies, but it is merely a mutation of the African Cheetah. The 'king Cheetah' has only been seen in the wild a handful of times, but it has been bred in captivity.

The Cheetah's paws have semi-retractable claws (known only in three other cat species - the Fishing Cat, the Flat-headed Cat and the Iriomote Cat) offering the cat extra grip in its high-speed pursuits. The ligament structure of the Cheetah's claws is the same as those of other cats; it simply lacks the sheath of skin and fur present in other varieties, and therefore the claws are always visible, with the exception of the dewclaw. The dewclaw itself is much shorter and straighter than other cats.

Adaptations that enable the Cheetah to run as fast as it does include large nostrils that allow for increased oxygen intake, and an enlarged heart and lungs that work together to circulate oxygen efficiently. During a typical chase its respiratory rate increases from 60 to 150 breaths per minute. While running, in addition to having good traction due to its semi-retractable claws, the Cheetah uses its tail as a rudder-like means of steering to allow it to make sharp turns, necessary to outflank prey who often make such turns to escape.

Unlike "true" big cats, the Cheetah can purr as it inhales, but cannot roar. By contrast, the big cats can roar but cannot purr, except while exhaling. However, the Cheetah is still considered by some to be the smallest of the big cats. While it is often mistaken for the Leopard, the Cheetah does have distinguishing features, such as the aforementioned long "tear-streak" lines that run from the corners of its eyes to its mouth. The body frame of the Cheetah is also very different from that of the leopard, most notably so in its thinner and longer tail, and unlike the leopard, its spots are not arranged into rosettes.

The Cheetah is a vulnerable species. Out of all the big cats, it is the least able to adapt to new environments. It has always proved difficult to breed in captivity, although recently a few zoos have been successful. Once widely shot for its fur, the Cheetah now suffers more from the loss of both habitat and prey. The Cheetah's natural enemies include hyenas, baboons, lions and leopards.

The Cheetah was formerly considered to be particularly primitive among the cats and to have evolved approximately 18 million years ago. New research, however puts the last common ancestor of all 40 existing species of feline more recently, at 11 million years. The same research indicates that the Cheetah, while highly derived morphologically, is not a particularly ancient lineage, having separated from its closest living relatives (the cougar Puma concolor and the jaguarundi Puma yaguarondi) around 5 million years ago.

Females reach sexual maturity within twenty to twenty-four months, and males around twelve months (although they do not usually mate until at least three years old), and mating occurs throughout the year. A recent study of Cheetahs in the Serengeti showed that female Cheetahs are sexually promiscuous and often have cubs by many different males.

Females give birth to up to nine cubs after a gestation period of ninety to ninety-eight days, although the average litter size is three to five. Cubs weigh from 150 to 300 grams (5 to 10 oz.) at birth. Unlike some other cats, the Cheetah is born with its characteristic spots. Cubs are also born with a downy underlying fur on their necks, called a mantle, extending to mid-back. This gives them a mane or Mohawk-type appearance; this fur is shed as the Cheetah grows older. It has been speculated that this mane gives a Cheetah cub the appearance of the ratel, to scare away potential aggressors.

Death rate is very high during the early weeks, and up to 90% of the cubs are killed during this time by lions, hyenas or even by eagles. Cubs leave their mother between thirteen and twenty months after birth. Life span is up to twelve years in wild, but up to twenty years in captivity.

Unlike males, females are solitary and tend to avoid each other, though some mother/daughter pairs have been known to be formed for small periods of time. The Cheetah has a unique, well-structured social order. Females live alone except when they are raising cubs and they raise their cubs on their own. The first eighteen months of a cub's life are important - cubs learn many lessons because survival depends on knowing how to hunt wild prey species and avoid other predators. At eighteen months, the mother leaves the cubs, who then form a sibling, or 'sib', group, that will stay together for another six months. At about two years, the female siblings leave the group, and the young males remain together for life.

Males are very sociable and will group together for life, usually with their brothers in the same litter; although if a cub is the only male in the litter then two or three lone males may group up, or a lone male may join an existing group. These groups are called coalitions. A coalition is six times more likely to obtain an animal territory than a lone male, although studies have shown that coalitions keep their territories just as long as lone males - between four to four and a half years.

Males are very territorial. Females' home ranges can be very large and trying to build a territory around several females' ranges is impossible to defend. Instead, males choose the points at which several of the females' home ranges overlap, creating a much smaller space, which can be properly defended against intruders while maximizing the chance of reproduction. Coalitions will try their utmost to maintain territories in order to find females with whom they will mate. The size of the territory also depends on the available resources; depending on the part of Africa, the size of a male's territory can vary greatly from 37 to 160 square kilometers.

Males mark their territory by urinating on objects that stand out, such as trees, logs, or termite mounds. The whole coalition contributes to the scent. Males will attempt to kill any intruders and fights result in serious injury or death.

Unlike males and other felines, females do not establish territories. Instead, the area they live in is termed a home range. These overlap with other females' home ranges; often it will be the sisters from the same litter or a daughter's home range overlapping with her mother's. Females, however, always hunt alone, although once their cubs reach the age of five to six weeks they take them along to show them how it is done. The size of a home range depends entirely on the availability of prey. Cheetahs in southern African woodlands have ranges as small as 34 square kilometres, while in some parts of Namibia they can reach 1,500 square kilometers. Although there have been no studies, it is expected that the home ranges of females in the Sahara desert have the largest of all the Cheetah populations.

The Cheetah is a carnivore, eating mostly mammals under 40 kilograms (90 lb), including Thomson's gazelles, Grant's gazelles, springboks and impalas. The young of larger mammals such as wildebeests and zebras are taken at times, adults, too, when the cats hunt in groups. Guineafowl and hares are also prey. While the other big cats mainly hunt by night, the Cheetah is a diurnal hunter. It hunts usually either early in the morning or later in the evening when it is not so hot, but there is still enough light - the

Cheetah hunts by vision rather than by scent. Prey is stalked to within 10-30 meters (30-100 ft), then chased. The chase is usually over in less than a minute, and if the Cheetah fails to make a quick catch, it will often give up rather than waste energy. The Cheetah has an average hunting success rate of around 50%, meaning that half of its chases result in a failure.

Another reason the Cheetah may give up is because running at such high speeds puts a great deal of strain on the Cheetah's body. When sprinting, the Cheetah's body temperature becomes so high that it would be deadly to continue - this is why the Cheetah is often seen resting even after it has caught its prey. While resting the Cheetah risks a 50% chance of losing its catch to other predators, such as lions, leopards, and baboons. If it is a hard chase, it sometimes needs to rest for half an hour or more. The Cheetah kills its prey by tripping it during the chase, then biting it on the underside of the throat to suffocate it, for the Cheetah is not strong enough to break the necks of the four-legged prey it mainly hunts. The bite may also puncture a vital artery in the neck. Then the Cheetah proceeds to devour its catch as quickly as possible before the kill is taken by stronger predators.

The Thompson's gazelle is one of their favorite catches - it is very plentiful on the east African plains. These small antelopes are sized just right since they are only several inches shorter than the Cheetah. They are about 23-28 inches (58-70 centimeters) tall and 28-43 inches (70-107 centimeters) long. Known as "tommys" these antelopes can run faster (up to 80 km/h or 49.71 mph) than anything except a Cheetah. Viewed from a great distance while grazing their black "swipe" pattern makes them look like a stick. Cheetahs favor fawns or half-grown antelope and look for animals which have strayed some distance from the group. They do not seek out old or weak animals. Cheetah may go several days without water - in a pinch they have been known to break open melons for fluid.

The Cheetah thrives in areas with vast expanses of land where prey is abundant. In Namibia, it has been found in a variety of habitats, including grasslands, savannahs, dense vegetation, and mountainous terrain. Ninety-five percent live on commercial farms. The Cheetah is found in the wild primarily in Africa, but in the past its range extended into India. Conservationists using camera traps have recently discovered surviving populations in Iran and are taking steps to protect them. In much of its former range, it was tamed by aristocrats and used to hunt antelopes in much the same way as is still done with members of the greyhound group of dogs. Aside from an estimated fifty Cheetahs living in Iran (Khorasan Province), the distribution of the Cheetah is now limited to Africa. There are five subspecies of Cheetah in the genus Acinonyx: four in Africa and one in Iran. The endangered subspecies Acinonyx jubatus venaticus lives in Asia (Iran). In 1990, there were reports in the Times of India of a Cheetah sighting in eastern India. There is a chance some Cheetahs remain in India, though it is doubtful. There have also been several unconfirmed reports of Asiatic Cheetahs in the Balochistan province of Pakistan, with at least one dead animal being recovered recently. The Cheetah prefers to live in an open biotope, such as semi-desert, prairie, and thick brush.

The genus name, Acinonyx, means "no-move-claw" in Greek, while the species name, jubatus, means "maned" in Latin, a reference to the mane found in Cheetah cubs.

The Cheetah has unusually low genetic variability and a very low sperm count, which also suffers from low motility and deformed flagellae. Skin grafts between non-related Cheetahs illustrate this point in that there is no rejection of the donor skin. It is thought that it went through a prolonged period of inbreeding following a genetic bottleneck during the last ice age. It probably evolved in Africa during the Miocene epoch (26 million to 7.5 million years ago), before migrating to Asia. New research by a team led by Warren Johnson and Stephen O’Brien of the Laboratory of Genomic Diversity (National Cancer Institute in Frederick, Maryland, United States) has recently placed the last common ancestor of all existing cat species as living in Asia 11 million years ago, which may lead to revision and refinement of existing ideas about Cheetah evolution. Now-extinct species include: Acinonyx pardinensis (Pliocene epoch), much larger than the modern Cheetah and found in Europe, India, and China; Acinonyx intermedius (mid-Pleistocene period), found over the same range. The extinct genus Miracinonyx was extremely Cheetah-like, but recent DNA analysis has shown that Miracinonyx inexpectatus, Miracinonyx studeri, and Miracinonyx trumani (early to late Pleistocene epoch), found in North America and called the "North American cheetah" are not true Cheetahs, instead being close relatives to the Cougar.