Genetics and classification
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 flagella. 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 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.
The cheetah's chest is deep and its waist is narrow. The coarse, short fur of the cheetah is tan with round black spots measuring from 2 to 3 cm (0.79 to 1.2 in) 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. Although it can reach high speeds, its body cannot stand long distance running. It is a sprinter.The adult cheetah weighs from 36 to 65 kg (79 to 140 lb). Its total body length is from 115 to 135 cm (45 to 53 in), while the tail can measure up to 84 cm (33 in) in length. Cheetah are 67 to 94 cm (26 to 37 in) in high at the shoulder. Males tend to be slightly larger than females and have slightly bigger heads, but there is not a 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 (35 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 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 that of 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 steeringto allow it to make sharp turns, necessary to outflank prey animals that 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's, 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 managed to succeed at this. Once widely hunted for its fur, the cheetah now suffers more from the loss of both habitat and prey.The cheetah was formerly considered to be particularly primitive among the cats and to have evolved approximately 18 million years ago. New research, however, suggests that the last common ancestor of all 40 existing species of felines lived more recently than that—about 11 million years ago. The same research indicates that the cheetah, while highly derived morphologically, is not of particularly ancient lineage, having separated from its closest living relatives (Puma concolor, the cougar, and Puma yaguarondi, the jaguarundi) around five million years ago. These felids have not changed appreciably since they first appeared in the fossil record.
Morphs and variations
The king cheetah is a rare mutation of cheetah characterized by a distinct pelt pattern. It was first noted in Zimbabwe in 1926. In 1927, the naturalist Reginald Innes Pocock declared it a separate species, but reversed this decision in 1939 due to lack of evidence, but in 1928, a skin purchased by Walter Rothschild was found to be intermediate in pattern between the king cheetah and spotted cheetah and Abel Chapman considered it to be a color form of the spotted cheetah. Twenty-two such skins were found between 1926 and 1974. Since 1927, the king cheetah was reported five more times in the wild. Although strangely marked skins had come from Africa, a live king cheetah was not photographed until 1974 in South Africa's Kruger National Park. Cryptozoologists Paul and Lena Bottriell photographed one during an expedition in 1975. They also managed to obtain stuffed specimens. It appeared larger than a spotted cheetah and its fur had a different texture. There was another wild sighting in 1986—the first in seven years. By 1987, thirty-eight specimens had been recorded, many from pelts.Its species status was resolved in 1981 when king cheetahs were born at the De Wildt Cheetah and Wildlife Centre in South Africa. In May 1981, two spotted sisters gave birth there and each litter contained one king cheetah. The sisters had both mated with a wild-caught male from the Transvaal area (where king cheetahs had been recorded). Further king cheetahs were later born at the Centre. It has been known to exist in Zimbabwe, Botswana and in the northern part of South Africa's Transvaal province. A recessive gene must be inherited from both parents in order for this pattern to appear- which is one reason why it is so rare.Other color variationsOther rare color morphs of the species include speckles, melanism, albinism and gray coloration. Most have been reported in Indian cheetahs, particularly in captive specimens kept for hunting.The Mughal Emperor of India, Jahangir, recorded having a white cheetah presented to him in 1608. In the memoirs of Tuzk-e-Jahangiri, the Emperor says that in the third year of his reign: Raja Bir Singh Deo brought a white cheetah to show me. Although other sorts of creatures, both birds and beasts have white varieties .... I had never seen a white cheetah. Its spots, which are (usually) black, were of a blue colour, and the whiteness of the body also inclined to blue-ishness. This suggests a chinchilla mutation which restricts the amount of pigment on the hair shaft. Although the spots were formed of black pigment, the less dense pigmentation gives a hazy, grayish effect. As well as Jahangir's white cheetah at Agra, a report of "incipient albinism" has come from Beaufort West according to Guggisberg.
In a letter to "Nature in East Africa", H. F. Stoneham reported a melanistic cheetah (black with ghost markings) in the Trans-Nzoia District of Kenya in 1925. Vesey Fitzgerald saw a melanistic cheetah in Zambia in the company of a spotted cheetah. Red (erythristic) cheetahs have dark tawny spots on a golden background. Cream (isabelline) cheetahs have pale red spots on a pale background. Some desert region cheetahs are unusually pale; probably they are better-camouflaged and therefore better hunters and more likely to breed and pass on their paler coloration. Blue (Maltese or grey) cheetahs have variously been described as white cheetahs with grey-blue spots (chinchilla) or pale grey cheetahs with darker grey spots (Maltese mutation). A cheetah with hardly any spots was shot in Tanzania on 1921 (Pocock), it had only a few spots on the neck and back and these were unusually small.
Range and habitat
There are several geographically isolated populations of cheetah, all of which are found in Africa or Southwestern Asia. A small population (estimated at about fifty) survive in the Khorasan Province of Iran, where conservationists are taking steps to protect them. It is possible, though doubtful, that some cheetahs remain in India. There have also been several unconfirmed reports of Asiatic Cheetahs in the Balochistan province of Pakistan, with at least one dead animal being discovered recently.The cheetah thrives in areas with vast expanses of land where prey is abundant. The cheetah likes to live in an open biotope, such as semi-desert, prairie, and thick brush, though it can be found in a variety of habitats. In Namibia, for example, it lives in grasslands, savannahs, areas of dense vegetation, and mountainous terrain.In much of its former range, the cheetah 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.
Reproduction and behavior
Females reach maturity in 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 study of cheetahs in the Serengeti showed that females 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 g (5.3 to 11 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 theappearance of the Honey Badger (Ratel), to scare away potential aggressors. Cubs leave their mother between thirteen and twenty months after birth. Life span is up to twelve years in the 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. In one Serengeti study by Caro and Collins (1987), 41% of the adult males were solitary, 40% lived in pairs and 19% lived in trios.
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 and 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 best 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 km2 (14 to 62 sq mi).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 those of their daughters, mothers, or sisters. Females always hunt alone, although cubs will accompany their mothers to learn to hunt once they reach the age of five to six weeks.The size of a home range depends entirely on the availability of prey. Cheetahs in southern African woodlands have ranges as small as 34 km2 (13 sq mi), while in some parts of Namibia they can reach 1,500 km2 (580 sq mi).
The cheetah cannot roar, but does have the following vocalizations:
* Chirping - When cheetahs attempt to find each other, or a mother tries to locate her
cubs, it uses a high-pitched barking called chirping. The chirps made by a cheetah cub
sound more like a bird chirping, and so are termed chirping.
* Churring or stuttering - This vocalization is emitted by a cheetah during social
meetings. A churr can be seen as a social invitation to other cheetahs, an expression of
interest, uncertainty, or appeasement or during meetings with the opposite sex (although
each sex churrs for different reasons).
* Growling - This vocalization is often accompanied by hissing and spitting and is
exhibited by the cheetah during annoyance, or when faced with danger.
* Yowling - This is an escalated version of growling, usually displayed when danger worsens.
* Purring - This is made when the cheetah is content, usually during pleasant social
meetings (mostly between cubs and their mothers). A characteristic of purring is that it is realised on both egressive and ingressive airstream. A purring cheetah can be heard on Robert Eklund's Ingressive Speech website or on Robert Eklund's Wildlife page.
Diet and hunting
The cheetah is a carnivore, eating mostly mammals under 40 kg (88 lb), including the Thomson's Gazelle, the Grant's gazelle, the springbok and the impala. The young of larger mammals such as wildebeests and zebras are taken at times, and 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 m (33–98 ft), then chased. This is usually over in less than a minute, and if the cheetah fails to make a catch quickly, it will give up. The cheetah has an average hunting success rate of around 50% - half of its chases result in capture.Running at speeds between 112 and 120 km/h (70 and 75 mph) 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 after it has caught its prey. 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 diet of a cheetah is dependent upon the area in which it lives. For example, on the East African plains, its preferred prey is the Thomson's Gazelle. This small antelope is shorter than the cheetah (about 53–67 cm (21–26 in) tall and 70–107 cm (28–42 in) long), and also cannot run faster than the cheetah (only up to 80 km/h (50 mph)), which combine to make it an appropriate prey. Cheetahs look for individuals which have strayed some distance from their group, and do not necessarily seek out old or weak ones.