Onager

From Wikipedia, the free encyclopedia
Jump to: navigation, search
This article is about the horse species. For the weapon, see Onager (siege weapon).
Onager
Rostov-on-Don Zoo Persian onager IMG 5268 1725.jpg
A Persian onager (Equus hemionus onager) at Rostov-on-Don Zoo, Russia.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Perissodactyla
Family: Equidae
Genus: Equus
Subgenus: Asinus
Species: E. hemionus
Binomial name
Equus hemionus
Pallas, 1775
Subspecies

E. h. hemionus
E. h. kulan
E. h. onager
E. h. khur
E. h. hemippus

Equus hemionus map.png
Equus hemionus range

The onager, also known as hemione or Asiatic wild ass[2] (Equus hemionus) is a large member of the genus Equus of the family Equidae (horse family) native to the deserts and other arid regions of Iran, Pakistan, India and Mongolia, including in cold regions of Kazakhstan, Uzbekistan and Turkmenistan.[3] It formerly had a wider range from southwest to central Asian countries, such as Israel, Saudi Arabia, Iraq, Syria, Afghanistan and Russia.

Like many other large grazing animals, the onager's range has contracted greatly under the pressures of poaching and habitat loss.[2] Of the five subspecies, one is extinct and at least two are endangered[2] (their status in China is not well known[2]).

Taxonomy[edit]

The specific name is Ancient Greek ἡμίονος (hēmíonos), from ἡμι- (hēmi-), half, and ὄνος (ónos), donkey; thus, half-donkey or mule. In Persian the archaic word gur preserves the second syllable of the common Indo-European term that includes ona/ono (donkey) and ger/gur (swift).

The species was commonly known as Asian wild ass, in which case the term "onager" was reserved for the E. h. onager subspecies,[2] more specifically known as the Persian onager. Until this day, the species share the same name, "onager".

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 that it is a distinct species.

Description[edit]

Onagers are a little larger than donkeys at about 290 kilograms (640 lb) and 2.1 metres (6.9 ft) (head-body length), and are a little more horse-like. They are short-legged compared to horses, and their coloring varies depending on the season. They are generally reddish-brown in color during the summer, becoming yellowish-brown in the winter months. They have a black stripe bordered in white that extends down the middle of the back.

Onagers are notoriously untamable. Equids were used in ancient Sumer to pull wagons circa 2600 BC, and then chariots on the Standard of Ur, circa 2550 BC. Clutton-Brock (1992) suggests that these were donkeys rather than onagers on the basis of a "shoulder stripe".[4] 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.[5][6]

Distribution and range[edit]

An Indian wild ass in Little Rann of Kutch, Gujarat, India.

The onagers' favored habitats are deserts, semi-deserts, arid grasslands, shrublands and mountain steppes. The Turkmenian kulan are known to live in hot and colder regions.

During late Pleistocene era around 40,000 years ago, the Asiatic wild ass ranged widely across Europe to northeastern Asia. The onager have been regionally extinct in Israel, Saudi Arabia, Iraq, Jordan, Syria and southern regions of Siberia.

The Mongolian wild ass lives in deserts of Mongolia and northern China and is the most common subspecies, however their populations have decreased to a few thousands due to years of poaching and habitat loss. It is regionally extinct in eastern Kazakhstan and Siberia. The Indian wild ass was once found throughout the arid parts and desert steppes of northwest India and Pakistan, but approximately 4,500 of them are found in a few very hot sanctuaries of Gujarat. The Persian onager is found in two sub-populations in southern and northern Iran. However, it is extinct in the wild of Afghanistan. The Turkmenian kulan used to be widespread in central to north Asia. However, it is now found only in Turkmenistan and has been reintroduced in southern Kazakhstan.

Threats[edit]

An Asiatic lion attacking an onager (Roman, c. AD 150).

The Asiatic wild ass is vulnerable to diseases as well. A disease known as the "South African horse sickness" had caused a major decline to the Indian wild ass in the 1960s. Fortunately, the subspecies is no longer under threat to such disease and is continuously increasing their numbers.

The onagers were once under threat by apex predators from India, Iran and Pakistan, as they used to be prey for Asiatic lions, Asian leopards, Asiatic cheetahs, tigers, striped hyenas and dholes. However, until today, the Asiatic wild ass are being strictly protected.

Conservation[edit]

A Persian onager in Augsburg Zoo.

There are various breeding programs for the onager subspecies in captivity and in the wild, which increases their numbers to save the endangered 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,[7] whilst the Persian onager alone has been reintroduced to the deserts of Saudi Arabia.

Subspecies[edit]

Widely recognized subspecies of the onager include:[2]

A sixth possible subspecies, the Gobi khulan (E. h. luteus,[1] also called the chigetai[8] or dziggetai) has been proposed, but may be synonymous with E. h. hemionus.

See also[edit]

References[edit]

  1. ^ a b Moehlman, P. D., Shah, N. & Feh, C. (2008). "Equus hemionus". IUCN Red List of Threatened Species. Version 2010.4. International Union for Conservation of Nature. Retrieved 7 Nov 2010. 
  2. ^ a b c d e f "Asiatic Wild Ass   Equus hemionus". IUCN.org. Gland, Switzerland: IUCN/SSC Equid Specialist Group. 
  3. ^ Grubb, P. (2005). "Order Perissodactyla". In Wilson, D.E.; Reeder, D.M. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 632. ISBN 978-0-8018-8221-0. OCLC 62265494. 
  4. ^ Clutton-Brock, Juliet (1992). Horse Power: A History of the Horse and the Donkey in Human Societies. Boston, Massachusetts, US: Harvard University Press. ISBN 978-0-674-40646-9. 
  5. ^ Heimpel, Wolfgang (1968). Tierbilder in der Sumerische Literatur. Italy: Studia Pohl 2. 
  6. ^ Maekawa, K. (1979). "The Ass and the Onager in Sumer in the Late Third Millennium B.C.". Acta Sumerologica' (Hiroshima) I: 35–62. 
  7. ^ Saltz, D. (1995). "Population dynamics of a reintroduced Asiatic wild ass (Equus Hemionus) herd". Ecological Applications 5 (2): 327–335. doi:10.2307/1942025. 
  8. ^ Porter, Valerie (ed.); Ian Lauder Mason (2002). Mason's World Dictionary of Livestock Breeds, Types, and Varieties (5th ed.). Wallingford: CABI. ISBN 0-85199-430-X. 
  • Duncan, P. (ed.). 1992. Zebras, Asses, and Horses: an Action Plan for the Conservation of Wild Equids. IUCN/SSC Equid Specialist Group. IUCN, Gland, Switzerland.[clarification needed]]]

External links[edit]