Przewalski's horse

Przewalski's horse
Conservation status
Endangered (ZSL 2006)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Perissodactyla Family: Equidae Genus: Equus Subgenus: Equus Species: E. ferus Subspecies: E. f. przewalskii
Trinomial name
Equus ferus przewalskii (Poliakov, 1881)
Range map

Przewalski's horse is a rare, wild horse of Asia, Equus ferus przewalskii, characterized by a stocky built, a dark brown mane and tail, pale brown or dun-colored flanks, and often faintly striped legs. It is the last remaining wild horse (Equus ferus) although some classify it as another species, Equus przewalskii, or as a subspecies, Equus caballus przewalskii, of the domestic horse, Equus caballus. Przewalski's horse is the closest living wild relative of the domestic horse, and Przewalski's horse and the domestic horse are the only equids (genus Equus or family Equidae) that can cross-breed and produce fertile offspring, although they have different numbers of chromosomes. Przewalski's horse is also known as the Asian wild horse, Mongolian wild horse, or takhi.

Most "wild" horses today, such as the American mustang or the Australian brumby, are actually feral animals, horses that were once domesticated but escaped and reverted to an apparently wild status. Przewalski's horse, on the other hand, has never been successfully domesticated and remains a truly wild animal today. The tarpan, Equus ferus ferus, was also a wild horse, but became extinct in the early twentieth century.

At one point, Przewalski's horse was extinct in the wild, but was reintroduced into the wild from zoos and is now considered endangered in the wild.

Overview and description

The horse or domestic horse (Equus caballus) is a sizable ungulate ("hoofed") mammal of the family Equidae and the genus Equus. Among the 10 living members of the Equus genus are zebras, donkeys, Przewalski's Horse (a rare Asian species), and hemionids (Onager or Equus hemionus). The donkey (Equus asinus), also known as the burro or domestic ass, like the domestic horse, has many breeds. Przewalski's Horse (Equus ferus przewalskii) and the domestic horse are the only equids that can cross-breed and produce fertile offspring.

Equidae is the family of horse-like animals, which belong to the order Perissodactyla. It is sometimes known as the horse family. Apart from the horse, other extant equids include assorted subspecies of donkey or ass, and the zebras. All of these are in the genus Equus. Equids are medium to large mammals, with long heads, and necks with a mane. Their legs are slender and end in a single, unguligrade toe, protected by a horny hoof. They have long, slender, tails, either ending in a tuft, or entirely covered in flowing hair. The pinnae ("ears") of equids are mobile, enabling them to easily localize the origin of sounds. They have two-color, or dichromatic vision. Their eyes are set back far on the head, giving them a wide angle of view, without entirely losing binocular vision. Equids also have a vomeronasal organ, that allows males to use the flehmen, or 'lip-curling' response to assess the sexual state of potential mates.

Equids are herbivores, and feed predominantly on tough, fibrous food, such as grasses and sedges. When in need, they will also eat other vegetable matter, such as leaves, fruits, or bark, but are normally grazers, not browsers. Unlike ruminants, with their complex stomachs, equids break down cellulose in the "hindgut" or cecum, a part of the colon.

Appearance

Przewalski's Horse is stockily built in comparison to domesticated horses, with shorter legs. Typical height is about 13 hands (1.32 m), length is about 2.1 m with a 90 cm tail. They weigh around 300 kg. The coat is similar to dun coloration in domestic horses. It varies from dark brown around the mane (which stands erect) to pale brown on the flanks and yellowish-white on the belly. The legs of the Przewalski's Horse are often faintly striped.

Behaviour

Przewalski's Horses

In the wild, Przewalski's Horses live in social groups consisting of a dominant stallion, a dominant lead mare, other mares, and their offspring. The patterns of their daily lives exhibit horse behavior similar to that of feral horse herds: Each group has a well-defined home range; within the range, the herd travels between three and six miles a day, spending time grazing, drinking, using salt licks and dozing. At night, the herd clusters and sleeps for about four hours. Ranges of different herds may overlap without conflict, as the stallions are more protective of their mares than their territory.

Stallions practice a form of scent marking and will establish piles of dung at intervals along routes they normally travel to warn other males of their presence. In addition, when a female in the herd urinates, the stallion will frequently urinate in the same place, to signal her membership in the herd to other males. The stallions can frequently be seen sniffing dung piles to confirm scent markings. ^{[citation needed]}

Taxonomy

Poliakov, who concluded that the animal was a wild horse species, gave it the official name Equus przewalskii (Poliakov 1881). However, authorities differ about the correct classification. Some hold it is a separate species, the last remnant of the wild horse Equus ferus, others hold it is a subspecies of Equus caballus. The question will only be answered with finality if or when the common ancestor from which domestic and Przewalski's horses diverged is determined. Although the Przewalski's horse has 66 chromosomes, compared to 64 in a domestic horse, the Przewalski's horse and the domestic horse are the only equids that cross-breed and produce fertile offspring, possessing 65 chromosomes. "The Przewalski horse can be crossed successfully with the domestic horse, producing offspring with 65 chromosomes. Unlike the offspring of a domestic horse and an animal such as a donkey or zebra, the offspring of a Przewalski/domestic horse is not sterile and can be crossed back to either species. If the offspring is crossed back to a domestic horse, the resulting animal will have 64 chromosomes and very few Przewalski characteristics."

Population

As of a census taken in 2005, the world population of these horses was about 1,500, all descended from 31 horses that were in captivity in 1945, mostly descended from approximately 15 captured around 1900. A cooperative venture between the Zoological Society of London and Mongolian scientists has resulted in successful reintroduction of these horses from zoos into their natural habitat in Mongolia, and as of 2005 there is a free-ranging population of 248 animals in the wild.

History

In the 15th century, Johann Schiltberger recorded one of the first European sightings of the horses in the journal of his trip to Mongolia as a prisoner of the Mongol Khan. The horse is named after Russian General Nikolai Przhevalsky (1839–1888) (the spelling of the horse breed as "Przewalski" derives from the Polish spelling of the name). He was an explorer and naturalist who described the horse in 1881, after having gone on an expedition to find it, based on rumours of its existence. Many of these horses were captured around 1900 by Carl Hagenbeck and placed in zoos. As noted above, about twelve to fifteen reproduced and formed today's population.

Przewalski's Horse at the Parc du Thot, France

The native population declined in the 20th century due to a combination of factors, with the wild population in Mongolia dying out in the 1960s. The last herd was sighted in 1967 and the last individual horse in 1969. Expeditions after this failed to locate any horses, and the species was designated "extinct in the wild" for over 30 years.

After 1945 only two captive populations in zoos remained: in Munich and in Prague Zoo. The most valuable group in Askania Nova was shot down by German soldiers during occupation and the group in the USA had died.

Przewalski's Horses

In 1977, the Foundation for the Preservation and Protection of the Przewalski Horse was founded by Jan and Inge Bouman, which started a program of exchange between captive populations in zoos throughout the world to reduce inbreeding, and later starting a breeding program of its own. In 1992, sixteen horses were released into the wild in Mongolia, followed by additional animals later on. These reintroduced horses successfully reproduced, and the status of the animal was changed from "extinct in the wild" to "endangered" in 2005. However, they are classified as "extinct in the wild" by the IUCN Red List, as they have not been reassessed since 1996. The area to which they were reintroduced became Khustain Nuruu National Park in 1998.

Preservation efforts

While dozens of zoos worldwide have Przewalski's Horses in small numbers, there are also specialized reserves dedicated primarily to the species.

The world's largest captive breeding program for Przewalski's horses is at the Askania Nova preserve in Ukraine. Several dozen Przewalski's horses were also released in the area evacuated after the Chernobyl accident, which now serves as a deserted de facto natural preserve. An intensely researched population of free-ranging animals was introduced to the Hortobágy puszta in Hungary; data on social structure, behavior, and diseases gathered from these animals is used to improve the Mongolian conservation effort.

Przewalski's Horse, Dubbo Zoo, Aust.

Three animals from this program live in a 12 acre (5 hectare) paddock in the Clocaenog Forest in North Wales, UK, on the site of a former Neolithic or Iron Age settlement. They were introduced there in 2004. The Forestry Commission hopes they will help recreate scenes from the Iron Age when horses similar to these roamed Britain freely.

Another herd exists at The Wilds Wildlife Preserve in Cumberland, Ohio, USA. The small herd of about 17 individuals is kept in a large area shared with other Asian animals. A small population is also kept by the Smithsonian Institution at a facility near Front Royal, Virginia and in the Smithsonian National Zoological Park in Washington, DC.

Recent advances in equine reproductive science have potential to further preserve and expand the gene pool. In October, 2007 scientists at the Smithsonian Institution's National Zoo successfully reversed a vasectomy on a Przewalski horse — the first operation of its kind on this species and possibly the first ever on any endangered species. While normally a vasectomy may be performed on an endangered animal under limited circumstances, particularly if an individual has already produced many offspring and its genes are overrepresented in the population, scientists realized the animal in question was one of the most genetically valuable Przewalski horses in the North American breeding program.

See also

• Mongolian domestic horse
• Wild horse
• Tarpan
• Onager
• Horse, see subsection "wild species surviving into modern times"
• Reintroduction
• Feral horse

References

ISBN links support NWE through referral fees

http://www.zsl.org/zsl-whipsnade-zoo/news/worlds-last-wild-horse-returns-from-the-brink,220,NS.html Worlds last wild horse returns from the brink Zoological Society of London (ZSL). 2006. Tuesday 10 January 2006

• Equid Specialist Group 1996. Equus ferus. In: IUCN 2004. 2004 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 24 December 2005. [2]
• Equid Specialist Group 1996. Equus ferus ssp. przewalskii. In: IUCN 2004. 2004 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 16 February 2006. [3]
• Forestry Commission. 2004. FC Wales turns clock back thousands of years with 'wild' solution to looking after ancient forest site. News release, No: 7001, 16 September 2004. [4]
• International Commission on Zoological Nomenclature. 2003. Opinion 2027 (Case 3010). Usage of 17 specific names based on wild species which are pre-dated by or contemporary with those based on domestic animals (Lepidoptera, Osteichthyes, Mammalia): conserved. Bull.Zool.Nomencl., 60:81-84. [5].
• Ishida, Nobushige and et al. (1995). Mitochondrial DNA sequences of various species of the genus Equus with special reference to the phylogenetic relationship between Przewalskii's wild horse and domestic horse. Journal of Molecular Evolution 41 (2): 180–188.
• Jansen, Thomas and et al. (2002). Mitochondrial DNA and the origins of the domestic horse. PNAS 99 (16): 10905–10910.
• King, S. R. B. and Gurnell, J. (2006). Scent-marking behaviour by stallions: an assessment of function in a reintroduced population of Przewalski horses (Equus ferus przewalskii). Journal of Zoology 272 (1): 30–36.
• Wakefield, S., Knowles, J., Zimmermann, W. and Van Dierendonck, M. 2002. "Status and action plan for the Przewalski's Horse (Equus ferus przewalski)". In: P.D. Moehlman (ed.) Equids: Zebras, Asses and Horses. Status Survey and Conservation Action Plan, pp. 82-92. IUCN/SSC Equid Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK. [6]
• Wilford, John Noble, "Foal by Foal, the Wildest of Horses Is Coming Back", New York Times, 2005-10-11.

External links

• ARKive - images and movies of the Przewalski's horse (Equus ferus przewalskii)
• Details of the re-introduction program for Przewalski's horse.
• Breeding an reintroduction program of the Przewalski's horse at Zoo Hellabrunn Munich
• Details of the history and captive breeding program for Przewalski's Horse.
• Umbrella organization of all institutions participating in the reintroduction of takhis in Mongolia
• General studbook of Przewalski's horse

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