Азия жабайы есегі (Equus hemionus)

Species of mammal
the Equid species

Speciesbox
| name = Onager
| fossil range =
| image = Rostov on Don Zoo Persian onager IMG 5268 1725. jpg
| image upright = 1.2
| image caption = A Persian onager (Equus hemionus onager) at Rostov on Don Zoo, Russia
| status = NT
| status system = IUCN3.1
| status ref =
| parent = Equus (Asinus)
| taxon = Equus hemionus Equus hemionus //'/ɛ//k//w//ə//s// //h//ɪ/'/m//aɪ//ə//n//ə//s/), also known as hemione or Asiatic wild ass, is a species of the family Equidae native to Asia. A member of the subgenus Asinus, the onager was described and given its binomial name by German zoologist Peter Simon Pallas in 1775. Six subspecies have been recognized, two of which are extinct. The Asiatic wild ass weighs about and reaches about head body length. They are reddish brown or yellowish brown in color and have broad dorsal stripe on the middle of the back. Unlike most horses and donkeys, onagers have never been domesticated. They are among the fastest mammals, as they can run as fast as to The onager is closely related to the African wild ass, as they both shared the same ancestor. The kiang, formerly considered a subspecies of Equus hemionus, is generally considered a distinct species, however, this has been questioned, with some genomic studies finding the kiang to be nested within the diversity of Equus hemionus. During early 20th century, the species lost most of its ranges in the Middle East and Eastern Asia. Today, onagers live in deserts and other arid regions of Iran, Pakistan, India, and Mongolia, including in Central Asian hot and cold deserts of Kazakhstan, Uzbekistan, Turkmenistan, and China. Other than deserts, it lives in grasslands, plains, steppes, and savannahs. Like many other large grazing animals, the onager's range has contracted greatly under the pressures of poaching and habitat loss. A new species called the kiang (E. kiang), a Tibetan relative, was previously considered to be a subspecies of the onager as E. hemionus kiang, but recent molecular studies indicate it to be a distinct species, having diverged from the closest relative of the Mongolian wild ass's ancestor less than 500,000 years ago. |Europe, Western Asia
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A sixth possible subspecies, the Gobi khulan (E. h. luteus, or dziggetai) has been proposed, but may be synonymous with E. h. hemionus. Debates over the taxonomic identity of the onager occurred until 1980. as of 2015, four living subspecies and one extinct subspecies of the Asiatic wild ass have been recognized. The Persian onager was formerly known as Equus onager, as it was thought to be a distinct species.

Onagers are the most horse like of wild asses. They are short legged compared with horses, and their coloring varies depending on the season. They are generally reddish brown in color during the summer, becoming yellowish brown or grayish brown in the winter. They have a black stripe bordered in white that extends down the middle of the back. The belly, the rump, and the muzzle are white in most onagers, except for the Mongolian wild ass that has a broad black dorsal stripe bordered with white. Onagers are larger than donkeys at about in size and in head body length. Male onagers are usually larger than females.

The genus Equus, which includes all extant equines, is believed to have evolved from Dinohippus via the intermediate form Plesippus. One of the oldest species is Equus simplicidens, described as zebra like with a donkey shaped head. The oldest fossil to date is about 3.5 million years old from Idaho, USA. The genus appears to have spread quickly into the Old World, with the similarly aged Equus livenzovensis documented from western Europe and Russia. Molecular phylogenies indicate the most recent common ancestor of all modern equids (members of the genus Equus) lived around 5.6 (3.9–7.8) million years ago (Mya). Direct paleogenomic sequencing of a 700,000 year old middle Pleistocene horse metapodial bone from Canada implies a more recent 4.07 Mya for the most recent common ancestor within the range of 4.0 to 4.5 Mya. The oldest divergencies are the Asian hemiones (subgenus E. (Asinus), including the kulan, onager, and kiang), followed by the African zebras (subgenera E. (Dolichohippus), and E. (Hippotigris)). All other modern forms including the domesticated horse (and many fossil Pliocene and Pleistocene forms) belong to the subgenus E. (Equus) which diverged about 4.8 (3.2–6.5) Mya. In the Middle East and the Indian subcontinent, Asiatic lions and tigers were the main predators of onagers. They were also formerly preyed upon by dholes, Asiatic cheetahs, and possibly bears, though they may have mostly preyed only on onager foals. In India, mugger crocodiles can be great threats to onagers during migratory river crossings. Currently, the main predator for onagers are gray wolves. However, like most equids, they are known to have antipredator behaviour. Groups of stallions cooperate and try to chase off predators. If threatened, onagers defend themselves and violently kick at the incoming predator.

The greatest threat facing the onager is poaching for meat and hides, and in some areas for use in traditional medicine. The extreme isolation of many subpopulations also threatens the species, as genetic problems can result from inbreeding. Overgrazing by livestock reduces food availability, and herders also reduce the availability of water at springs. The cutting down of nutritious shrubs and bushes exacerbates the problem. Furthermore, a series of drought years could have devastating effects on this beleaguered species. Habitat loss and fragmentation are also major threats to the onager, a particular concern in Mongolia as a result of the increasingly dense network of roads, railway lines, and fences required to support mining activities. The Asiatic wild ass is also vulnerable to diseases. A disease known as the "South African horse sickness" caused a major decline to the Indian wild ass population in the 1960s. However, the subspecies is no longer under threat to such disease and is continuously increasing in number.

Various breeding programs have been started for the onager subspecies in captivity and in the wild, which increases their numbers to save the endangered species. The species is legally protected in many of the countries in which it occurs. The priority for future conservation measures is to ensure the protection of this species in particularly vulnerable parts of its range, to encourage the involvement of local people in the conservation of the onager, and to conduct further research into the behavior, ecology, and taxonomy of the species. Two onager subspecies, the Persian onager and the Turkmenian kulan are being reintroduced to their former ranges, including in other regions the Syrian wild ass used to occur in the Middle East. The two subspecies have been reintroduced to the wild of Israel since 1982, and had been breeding hybrids there, whilst the Persian onager alone has been reintroduced to Jordan and the deserts of Saudi Arabia.

Onagers are notoriously difficult to tame. Equids were used in ancient Sumer to pull wagons , and then chariots on the Standard of Ur, Clutton Brock (1992) suggests that these were donkeys rather than onagers on the basis of a "shoulder stripe". However, close examination of the animals (equids, sheep and cattle) on both sides of the piece indicate that what appears to be a stripe may well be a harness, a trapping, or a joint in the inlay. Genetic testing of skeletons from that era shows that they were kungas, a cross between an onager and a donkey.