Przewalski’s Horse

Przewalski's horse
Przewalski's horse at Khustain Nuruu National Park
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Perissodactyla
Family: Equidae
Genus: Equus
Subgenus: E. (Equus)
Species: E. ferus
Subspecies: E. f. przewalskii
Trinomial name
Equus ferus przewalskii
(L. S. Poliakov, 1881)
Przewalski's horse range
(reintroduced)
Synonyms

hagenbecki Matschie, 1903
prjevalskii Ewart, 1903
typicus
Hilzheimer, 1909

Przewalski's horse (pronounced /ʃɨˈvælski/ or /zɨˈvɑːlski/ ; Khalkha Mongolian: тахь, takhi; Ak Kaba Tuvan: [daɣə//daɢə] dagy; Polish: [pʂɛˈvalski]; Equus ferus przewalskii)[2] or Dzungarian horse, is a rare and endangered subspecies of wild horse (Equus ferus) native to the steppes of central Asia, specifically Mongolia.[3] At one time extinct in the wild (in Mongolia, the last wild Przewalski's horses had been seen in 1966), it has been reintroduced to its native habitat in Mongolia at the Khustain Nuruu National Park, Takhin Tal Nature Reserve, and Khomiin Tal.[1] The taxonomic position is still debated, and some taxonomists treat Przewalski's horse as a species, Equus przewalskii.

Common names for this equine include Asian wild horse, Przewalski's wild horse, Mongolian wild horse, and tahki. Historical but obsolete names include true tarpan[4] and Mongolian tarpan. The horse is named after the Russian geographer and explorer Nikolai Przhevalsky.

Most "wild" horses today, such as the American Mustang or the Australian Brumby, are actually feral horses descended from domesticated animals that escaped and adapted to life in the wild. In contrast, Przewalski's horse has never been domesticated and remains a truly wild animal today. Przewalski's horse is one of three known subspecies of Equus ferus, the others being the domesticated horse, Equus ferus caballus and the extinct tarpan (Equus ferus ferus). The Przewalski's horse is considered the only remaining truly wild "horse" in the world and may be the closest living wild relative of the domesticated horse. There are still a number of other wild equines, including three species of zebra and various subspecies of the African wild ass, onager (including the Mongolian wild ass), and kiang.

Taxonomy

The Przewalski's horse was described in 1881 by L. S. Poliakov. The taxonomic position of Przewalski's horse has always been problematic and no consensus exists whether it is a full species (Equus przewalskii), a subspecies of the wild horse (Equus ferus przewalskii), or even a sub-population of the horse (Equus ferus).[5][6][7] Studies using DNA have been inconclusive, in part due to crossing domestic horses into the Przewalski's horse as well as the limited genetic variation present in the founder population of the Przewalski's horse. A 2009 molecular study using ancient DNA recovered from archaeological finds like bones and teeth places the Przewalski's horse in the middle of the domesticated horses,[7] but 2011 mitochondrial DNA analysis suggests that the Przewalski and the modern domestic horse diverged some 160,000 years ago.[8] An analysis based on whole genome sequencing and calibration with DNA from old horse bones gave a divergence date of 38–72 thousand years ago.[9] The karyotype of the domestic horse differs from that of Przewalski’s horse by an extra chromosome pair either because of the fission of domestic horse chromosome 5 in Przewalski’s horse or fusion of Przewalski’s horse chromosomes 23 and 24 in the domestic horse. In comparison, the chromosomal differences between domestic horses and zebras include numerous translocations, fusions, and inversions. Przewalski’s horse is known to have the highest diploid chromosome number among all equine species. Przewalski’s horse can interbreed with the domestic horse and produce fertile offspring (65 chromosomes).[5]

Population

All Przewalski horses in the world are descended from nine of the 31 horses in captivity in 1945.[10] These nine horses were 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 2011 there is an estimated free-ranging population of over 300 in the wild.[11] From a population of 31 horses in captivity in 1945, the total number of these horses by the early 1990s was over 1,500.[12]

Reproduction

Przewalski females are able to give birth at the age of three and have a pregnancy period of about 11 to 12 months. Their reproduction process is seasonal and in Mongolia the season is towards the end of either May, June, or July. Mating stallions do not start looking for mating partners until the age of five. Instinctually the stallion will look to create his own group of mares or else wander until he finds a group with its own leader. If the stallion finds a group of mares with its own leader, the stallion will usually fight the other leader stallion of the group. The mares will adjust and follow whoever is victorious of the stallions. After birth, the foal can almost stand immediately (only taking about an hour or so)and can walk on its own. The foals also drink milk from the mother mare.

Characteristics

Przewalski's horse is stockily built in comparison to domesticated horses, with shorter legs. Typical height is about 13 hands (52 inches, 132 cm), length is about 2.1 m (6 ft 11 in). They weigh around 300 kilograms (660 lb). The coat is generally dun in color with pangaré features, varying from dark brown around the mane (which stands erect) to pale brown on the flanks and yellowish-white on the belly and around the muzzle. The legs of Przewalski's horse are often faintly striped, also typical of primitive markings.[13] The tail is about 90 cm (35.43 in) long, with a longer dock and shorter hair than seen in domesticated horses.

The hooves of the Przewalksi's horse are longer in the back and have significantly thicker sole horn than other feral horses. This is beneficial as it improves the performance of the hooves.

The Przewalski's horse has 66 chromosomes, compared to 64 in all other horse species.[14]

Behavior

Main article: Horse behavior

In the wild, Przewalski's horses live in small, permanent family groups consisting of one adult stallion, one to three mares, and their common offspring. Offspring stay in the family group until they are no longer dependent, usually at two or three years old. Bachelor stallions, and sometimes old stallions, join bachelor groups. Family groups can join together to form a herd that moves together.

The patterns of their daily lives exhibit horse behavior similar to that of feral horse herds. Stallions herd, drive and defend all members of their family, while the mare often displays leadership in the family. Stallions and mares stay with their preferred partner for years. While behavioral synchronization is high among mares, stallions other than the main harem stallion are generally less stable in this respect.

Horses maintain visual contact with their family and herd at all times and have a host of ways to communicate with one another, including vocalizations, scent marking, and a wide range of visual and tactile signals. Each kick, groom, tilt of the ear, or other contact with another horse is a means of communicating. This constant communication leads to complex social behaviors among Przewalski's horses.[15]

Diet

The Przewalski horse’s diet consists mostly of vegetation. There are many types of plant species in a typical Przewalski horse environment including: Erytria repens, Carex spp., and Fabaceae Asteracea.[16] While the horses eat a variety of different plant species, they tend to favor one species during a specific time of the year. In other words, the Przewalski horses have seasonal food preferences. In the springtime, Przewalski horses favor Elytrigia repens, Corynephorus canescens, Festuca valesiaca and Chenopodium albuy. In early summer they favor Dactylis glomerata and Trifolium and in late summer, they gravitate towards Elytrygia repens and Vicia cracca.[16] As the seasons change, so does the Przewalski’s food preferences. In winter, for example, the horses eat Salix spp., Pyrus communis, Malus sylvatica, Pinus sylvestis, Rosa spp., and Alnus spp. Additionally, Przewalski horses will dig for Festuca spp., Bromopsis inermis and Elytrigia repens that grow beneath the ice and snow. The Przewalski horse’s seasonal diet, specifically their winter diet, is very similar to the diet of domestic horses.[16][17] Studies have suggested that in the winter time, Przewalski horses experience hypodermis. Hypodermis is a condition in which one’s metabolic rate slows down. This means that in the winter time, Przewalski horse’s process their food slower than they do during other times of the year.[18] Looking at the species diet overall, however, Przewalski horses most often eat Elytrigia repens, Trifolium pretense, Vicia cracca, Poa trivialis, Dactylis glomerata and Bromus inermis.[16]

Water, along with grassy vegetation, is another major component of the Przewalski horse’s diet. A study, conducted by K.M. Scheibe and a team of scientist’s, documented the water consumption of 12 female Przewalski horses that were living in a semireserve over a course of 17 months.[19] Their results show that, on average, a Przewalski horse drinks between 2.4 and 8.3 liters of water a day, which is less than the amount of water a domestic horse drinks daily.[19] In fact, the Przewalski horse that consumed the most water in the study drank on average 8.6 liters of water a day. This almost equals the lowest amount of water consumption for a domestic horse which is 8.4 liters a day.[19]

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.[20] The horse is named after the Russian colonel Nikolai Przhevalsky (1839–1888) (the name is of Polish origin and "Przewalski" is the Polish spelling). He was the explorer and naturalist who first described the horse in 1881, after having gone on an expedition to find it, based on rumors 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.

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 had been designated "extinct in the wild" for over 30 years.

After 1945 only two captive populations in zoos remained, in Munich and in Prague. The most valuable group, in Askania Nova, Ukraine, was shot by German soldiers during World War II occupation, and the group in the United States had died out. Competition with livestock, hunting, capture of foals for zoological collections, military activities, and harsh winters recorded in 1945, 1948 and 1956 are considered to be the main causes of the decline in the Przewalksi's horse population.

By the end of the 1950s, only 12 individual Przewalski's horses were left in the world.[21]


In 1977, the

Since 1986, Chinese researchers have bred Prezewalkski's horses in captivity, with the program seeing over twenty years of success.

In 1992, sixteen horses were released into the wild in Mongolia, followed by additional animals later on. One of the areas to which they were reintroduced became Association Takh to a third reintroduction site in the buffer zone of the Khar Us Nuur National Park, in the northern edge of the Gobi ecoregion. In the winter of 2009-2010, one of the worst "dzud" or snowy winter conditions ever hit Mongolia.The Przewalski's horse population in the Great Gobi B SPA was drastically impacted, providing clear evidence of the risks associated with re-introducing small and sequestered species in unpredictable and unfamiliar environments.

Since 2011, Prague Zoo has transported 12 horses to Mongolia in three rounds, in cooperation with partners (Czech Air Force, European Breeding Programme for Przewalski´s Horses, Association pour de cheval du Przewalski : Takh, Czech Development Agency, Czech Embassy in Mongolia and others) and it plans to continue to return horses to the wild in future. In the framework of the project Return of the Wild Horses it sustains its activities by supporting local inhabitants. The Zoo has the longest uninterrupted history of breeding of Przewalski´s Horses in the world and keeps the studbook of this species.

The reintroduced horses successfully reproduced, and the status of the animal was changed from "extinct in the wild" to "endangered" in 2005.[12] On the IUCN Red List, they were reclassified from "extinct in the wild" to "critically endangered" after a reassessment in 2008[22] and from "critically endangered" to "endangered" after a 2011 reassessment.[11]

Conservation 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.[23] In Chernobyl, the population reproduced at a high rate, reaching up to 200 individuals until poachers decreased their number to just 60 in recent years. An intensely researched population of free-ranging animals was also 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.

Several American zoos also collaborated in breeding Equus ferus przewalskii from 1979 to 1982.[24] Recent advances in equine reproductive science in the United States also 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's 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's horses in the North American breeding program.[25] The first birth by artificial insemination occurred on July 27, 2013 at the Smithsonian Conservation Biology Institute.[26][27]

Le Villaret, located in the

The Przewalski's Horse Reintroduction Project of China was initiated in 1985 when 11 wild horses were imported from overseas. After more than two decades of effort, the Xinjiang Wild Horse Breeding Centre has bred a large number of the horses, of which 55 were released into the Kalamely Mountain area. The animals quickly adapted to their new environment. In 1988, six foals were born and survived, and by 2001 there were over 100 horses at the centre.

Reintroductions organized by western European countries started in 1990s. These were later stopped, mostly for financial reasons. Prague Zoo started a new cycle of transporting horses to the wild, which, with the support of public and many strategic partners, continues today.

See also

Notes

References

  • Boyd, Lee and Katherine A. Houpt. (1994). OCLC 28256312
  • Forestry Commission. 2004. FC Wales turns clock back thousands of years with 'wild' solution to looking after ancient forest site. News release, No: 7001, September 16, 2004. [1]
  • 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. [2].
  • Van, Cleaf K. Przewalski's Horses. Edina, Minn: ABDO Pub. Co, 2006. Print.
  • 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. [3]
  • [4]
  • http://video.pbs.org/video/2157025070/
  • http://www.china.org.cn/english/environment/237442.htm
    • Cao Jie, Przewalski's Horse Reintroduction Project of China
  • [5])
  • Slivinska, Kateryna, and Grzegorz Kopij. "Diet of the Przewalski's Horse Equus Przewalskii in the Chernobyl Exclusion Zone." POLISH JOURNAL OF ECOLOGY 59 (2011): 841-47. Web of Knowledge. Thomson Reuters. Web. 22 Oct. 2013."
  • Scheibe, KM, K. Eichhorn, B. Kalz, WJ Streich, and A. Scheibe. "Water Consumption and Watering Behavior of Przewalski Horses (Equus Ferus Przewalskii) in a Semireserve." Zoo Biology 17.3 (1998): 181-92. Web of Science. Web. 24 Oct. 2013.."
  • Brinkmann, Lea, Martina Gerken, and Alexander Riek. "Adaptation Strategies to Seasonal Changes in Environmental Conditions of a Domesticated Horse Breed, the Shetland Pony(Equus Ferus Caballus)." Journal of Experimental Biology 215.7 (2012): 1061-068. Webof Knowledge. Web. 24 Oct. 2013. ."
  • Ferreira, Luis Miguel M., Rafael Celaya, Raquel Benavides, Berta M. Jauregui, Urcesino Garcia, Ana Sofia Santos, Rocio Rosa Garcia, Miguel Antonio M. Rodrigues, and Koldo Osoro. "Foraging Behaviour of Domestic Herbivore Species Grazing on Heathlands Associated with Improved Pasture Areas." Livestock Science 155.2-3 (2013): 373-83. Web of Science. Web. 24 Oct. 2013.

Further reading

  • Heptner, V. G. ; Nasimovich, A. A. ; Bannikov, A. G. ; Hoffman, R. S. (1988) , Volume I, Washington, D.C. : Smithsonian Institution Libraries and National Science Foundation

External links

  • ARKive -
  • Details of the re-introduction program for Przewalski's horse.
  • Umbrella organization of all institutions participating in the reintroduction of takhis in Mongolia
  • General studbook of Przewalski's horse
  • Association Takh - Przewalski horse conservation organization, reintroduced the species to Mongolia in 2004 and 2005 and continues research and conservation on the Mongolian steppe.

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