Przewalski's Horse, Equus ferus przewalski
Minor updates January 2012, July 2013
TAXONOMY & NOMENCLATURE
Equus caballus Linnaeus, (1758). Syst. Nat., 10th ed., 1:73.
(Agusti & Anton 2005) (Bennett & Hoffmann, 1999) (Bowling & Ruvinsky 2000) (Boyd, 1994) (Forstén 1988) (Froehlich 2002) (Groves, 2002) (Groves & Ryder 2000) (Hooker 2008) (Oakenfull et al 2000)
(Ryder 2009) (Steiner & Ryder 2011) (Villa et al. 2001) (Wilson & Reeder, 2005)
Equus ferus Boddaert (1785).
Equus przewalskii Polyakov (1881).
Equus ferus przewalskii Groves (1986).
Order: Perissodactyla (Horses, rhinos, tapirs)
Family: Equidae (Horses)
Genus: Equus (only remaining genus in the family)
Species: Equus asinus (domestic donkey)
Species: Equus africanus (African wild ass)
Species: Equus hemionus (Asiatic wild ass / Onager)
Species: Equus kiang (Tibetan wild ass)
Species: Equus ferus (wild horse)
Subspecies: Equus ferus przewalskii (Przewalski’s wild horse)
Species: Equus caballus (domestic horse)
Species: Equus grevyi (Grevy’s zebra)
Species: Equus burchellii (Plains / Burchellii’s zebra)
Species: Equus quagga (Quagga) EXTINCT
Species: Equus zebra (Mountain / Hartmann’s zebra)
- Horses were previously assigned to 2 different species, Equus caballus and E. przewalskii. In 1986 and 1994 Colin Groves, a leading taxonomist, proposed using E caballus for all domestic horses and E. ferus for the 2 wild horses:
- E ferus przewalskii = Przewalski horse
- E ferus ferus = Tarpan (extinct in the wild around 1897 )
- The Equus ferus przewalskii has 66 chromosomes, Equus caballus has 64; interbreeding results in fertile offspring with 65 chromosomes. (NOTE: It is a popular misconception that different species cannot interbreed. Species do not interbreed under natural conditions.)
- Named for 19th century Russian explorer, Colonel Nikolai Przewalski (pronounced zheh-VAHL-skee) who sent a skull and skin to the St. Petersburg Zoological Museum. I.S. Poliakov, conservator, declared the horse a new species : Equus przewalskii.
- Common Names: Przewalski’s wild horse, Asiatic wild horse, Mongolian wild horse, Mongolian takh, Takhi (spirit horse)
Equid Evolutionary History
- Horses diverged from rhinos between 54 and 58 million years ago (Early Eocene) (Ryder 2009)
- Horse lineages are called the hippomorphs; tapirs and rhinos are the ceratomorphs.
- Most likely horses first dispersed from Europe to North America at the beginning of the Eocene (Hooker 2008)
- Pliolophus is now considered the earliest horse; it is closely related Hyracotherium from North America (Froehlich 2002)
- Pliolophus had four hooves on front limbs, three on rear, with short legs and was half the size of a fox terrier (Hooker 2008) (Agusti & Anton 2005)
- The horse family, Equidae, has three main divisions based on anatomy and DNA studies (Oakenfull et al 2000)
- The caballines - include domestic horse and Equus przewalskii, a wild ancestor
- The asses - include domestic donkey, African wild asses, and the hemionines (Asiatic onager and kiang)
- The genus Equus likely originated 4.0-4.5 million years ago (Orlando et al. 2013)
- Conclusions based on genome sequences of a Late Pleistocene horse, 5 modern domestic horse breeds (Equus ferus caballus), a Przewalski’s horse (E. f. przewalskii), and a donkey (E. asinus) (Orlando et al. 2013)
- Previously believed to have emerged 2-4 million years ago (Pliocene) (Oakenfull et al 2000)
(Steiner & Ryder 2011)
- Equus dispersed from North America to Eurasia around 2.6 million years ago (Steiner & Ryder 2011)
- The modern horse genus Equus probably evolved in North America and migrated across the Bering land bridge into Asia and Europe (Steiner & Ryder 2011)
- Przewalski's horses are closely related to but not direct ancestors of modern domestic horses, according to recent DNA studies (Goto et al. 2011; Lau 2009; Orlando et al. 2013; Vilà et al. 2001)
- Diverged from modern domestic horses about 38,000-72,000 years ago (Orlando et al. 2013)
- Nucleotide diversity values indicate unique evolutionary histories for Przewalski's and domestic horses (Lau 2009)
- Przewalski's horses are only surviving wild horse
- DNA evidence shows no recent admixture with domestic horses (Orlando et al. 2013)
Equid Cultural History
- 30,000 years ago wild horses were hunted as prey by prehistoric man.
- 20,000 years ago rock art engravings/paintings of wild horses in Italy, France and Spain
- 10,000 years ago massive extinctions in North and South America wiped out all horse species, mammoths, and saber-tooth tigers. In Eurasia and Africa, 7 equid species survived.
- 3,000 BC domestication began – wildest horses killed for food, tamest kept for breeding
- 900 A.D. First account of wild horse written by a Tibetan monk
- 1226 A.D. Seen by Genghis Khan during one of his Mongolian campaigns
- 1750 Manchurian emperor shot 200-300 in a single day
- 1881 Skull and hide presented to Zoological Museum in St. Petersburg and Przewalski’s horse became known to the western world
- After WWII a dramatic declines due to hunting, military activities, climate change, livestock competition and numerous collecting expeditions
- 1969 last confirmed sighting in southwestern part of Mongolia
DISTRIBUTION & HABITAT
(Boyd & King 2011) (Ryder, 1990) (Boyd & Houpt, 1994) (Wakefield, et al., 2006)
- Roamed widely over central Asia, China, and western Europe in prehistoric times
- Historic range isn't precisely known (Boyd & King 2011)
- Several researchers suggest Eurasian steppes were home to Przewalski's horses before they were pushed into more arid Gobi Deser
- Last confirmed observation in the wild was 1969
- Prior to extinction, populations were found in eastern Kazakhstan, western Mongolia, and northern China
- As of 2011 there are 306 free-ranging reintroduced and native-born Przewalski's horses in Mongolia (Boyd et al. 2011)(Boyd et al. 201
- Large breeding-reserves established worldwide (in and outside historic range) to prepare individuals for release
- Le Villaret (Massif Central, France)
- Buchara (Uzbekistan)
- Hortobagy National Park (Hungary)
- Chernobyl (Ukraine)
- Jimsar (China)
- Gansu National Park(China)
- Anxi Gobi Nature Reserve (China)
- Reintroduction Projects in Mongolia
- Takhin Tal (since 1992)
- Hustain Nuruu (since 1992)
- Khomii tal (in preparation)
- Known to inhabit semi-arid and steppe grasslands at 100-1400 meters altitude
- Dense vegetation: saxaul (Haloxylon ammodendron), wormwood (Artemisia incana), tamarisk (Salicornia herbacea), and various other grasses.
(Boyd & Houpt, 1994) (Mohr, 1959) (Groves, 1994)
Weight: Males & females ~ 200-300 kg (440-660 lb.)
Height (at the withers / base of neck): Males: 1.42 m (4.65 ft); females: 1.37 m (4.5 ft) average
Length: 2.1 m (7ft.) for both sexes average
Tail length: 90 cm (3 ft) average
- Smaller than most domestic horses
- Thick, short neck and short limbs, compact build.
- Iris of eye is usually brown, but some are blue
- Sheds mane and tail annually unlike domestic horses.
- Mane is dark brown to black and stands upright with no forelock. Domestic horses have long, falling manes
- Dock of tail is shorthaired; hairs get gradually longer along the sides. Domestic horses have long guard hairs throughout tail.
- Muzzle is short and high, lower margin of jaw is straight.
- Two color types found: bright yellowish-red-brown and pale grey-yellow.
- Head and neck darker than the body.
- Underparts lighter than the flanks.
- 3-10 thin dark stripes on legs.
- Dark dorsal stripe (“eel-mark”) runs from mane down back to tail-tuft.
- Muzzle is light-colored, often white, and margins of nostrils are dark.
BEHAVIOR & ECOLOGY
(Boyd & Houpt, 1994) (Bouman, 1986) (Boyd 1988) (Mohr, 1971)
- Behavioral information comes mainly from captive populations. Natural behavior of stallions has been compromised.
- Projections of wild population behavior are made by studying feral horses and from limited information on reintroduction efforts.
- Ethogram is published in Boyd & Houpt p. 196-208
Activity Cycle (24-hour study of National Zoo Harem at
Front Royal in 1988)
- <46% feeding
- .5% drinking
- 20.5% standing
- 16% stand-resting
- 2% self-grooming
- 2% mutual grooming
- 7% locomotion
- 1% playing
- 5% recumbency
Feeding peaked at night (68% between 2000-2400)
Recumbency peaked at night (most from 0000-0400)
- Wild horses travel single file to avoid danger. Stallion sets course, maintains order and takes
up rear location to protect herd
- Wild equids spend ~ 70% of time grazing and roam several km/day
- Horses are gregarious by nature
- Harem groups are typically formed with one dominant stallion, mares, and their young foals.
- Every herd has a dominance hierarchy. Kinship influences behavior
- Wild stallion has pronounced instinct to guard by constantly rounding-up herd of mares.
- Formation of bachelor herds for young stallions is important for proper socialization
- Mutual grooming – partners stand in reverse parallel position. Teeth are used to gently bite each others coat
- Wild stallions subdue mares with ‘lightening’ bites to crest and occasionally legs. May chase and then turn and kick with hind legs. Can then control with a ‘glance’
- When extremely angry (and prepared to fight), stallion lowers head until it almost touches the ground and circles mares or another stallion, looking up with a fierce expression
- Dominant stallions within a herd will become aggressive with young males at approximately two years of age, at which point young males leave the harem group.
- Rate of aggression increases when horses are confined in smaller areas.
- In groups that have been part of reintroduction efforts, dominant stallions in harem groups take on leadership role, defending the herd against intruders and predators, and herding mares.
- When threatening or being threatened, ears are flattened against the skull, teeth exposed
- Neighing (indicates expectancy – food, water, another horse)
- 3 types of snorts: frustration, fear, and nostril cleaning. Can be an ‘alarm call’
- Grunting ‘laugh’ is given in encounters with aggression, by either the instigator or recipient. Used by stallion in courtship. Sometimes punctuated with sharp squeal
- Nicker is given in care-seeking or care-offering situation
- Stallions smell urine and feces of mares in their harem groups to determine estrus. (flehmen)
- Stallions exhibit marking behaviors and create stud piles to indicate territorial possession and harem possession to other stallions in the area.
- Snapping, champing, Toothclapping – usually employed by young animals
- Bite with ears back, neck extended
- Kicking with hind legs
- Herding (snaking) – Usually by stallion to drive mares.
- Head and neck may be moved in snake-lie manner.
- 2 stallions prance next to each other with necks arched
DIET & FEEDING
(Boyd & Houpt, 1994) (Scheibe, et al 1998)
Daily food intake
- Estimated water intake = 2.4 – 8.3 liters daily. Significant individual variation
- 5.5 - 7.0 kg of hay = daily consumption
- In general, feeding requirements are similar to those of domestic horses. Water consumption lower than domestic horses
- Quick consumption of food in captivity can cause animals to fill their time with aberrant behavior – (wind-sucking – ingesting air, wood chewing, eating feces, eating sand)
- Vitamin E deficiency is common, due to a possible genetic predisposition. Can be mitigated with supplementation.
- Ingestion of sand can cause colic.
- Able to use sharp hooves to dig holes in ground to access water
REPRODUCTION & DEVELOPMENT
(Boyd & Houpt, 1994) (Monfort, et al, 1991) (Asa, 2002) (National Geographic) (Klingel 1990)
- Mares first conception ~4-years. (as early as 2 years)
- Mares remain fertile until 20 years of age – 24 years is oldest recorded birth
- Stallion testes do not descend until 2.5 to 3 years of age—delayed descent is also observed in onagers, wild asses, and zebras.
- Immature males may be incapable of breeding due to subordination to older stallions/males or incompetent sexual behavior.
- Stallions generally begin copulation at 5 years of age.
- Continue copulation until over 30 years of age.
- Seasonally polyestrous. In North America, cycles begin in early spring and last 7-8 months
- Stallions exhibit seasonal changes in sperm production and sexual behavior during spring and summer
- Mare backs into stallion or stands in front of him to indicate receptivity. Ears turned back but not flattened, lips relaxed. She may urinate
- Mounting – stallion may rest chin on mares back to test willingness to stand, and then rear and place his forelimbs anterior to the mare’s pelvis.
- Approximately 11 months ( 320-343 days)
- Mares ready to foal leave herd to seek quiet place. Return probably coincides with heat (9 days after birth)
- Birth Weight:~30 kg (66 pounds)
Foals – Remain with dam for first 2 years
- Day 1 – stands, walks, trots, nibbles forage, neighs
- 1 week – grazes – eats hay and grain, solitary play, defensive kicking, eats adult feces
- 1 month - 39% of time resting. Begins playing with others in age group, older brothers and sisters
- 1-2 months – Nursing declines from 8.5% to 2.4%, Begins to leave mother’s side and interact with peers
- 5-months – Spend same amount of time feeding as an adult, begin drinking water
- 1 young / year>
- Mares who conceive right after delivering a foal, tend to wean the foal around 1 year
- Mares who fail to conceive continue nursing for several years
PATHOLOGY AND DISEASES
(Robert 2005) (Boyd & Houpt, 2002)
- In captivity, Przewalski’s horses are vaccinated for tetanus, encephalitis, influenza, and rabies.
- Causes of death fall into 9 categories:
- Abortions, stillbirth, neonatal mortality
- Gastrointestinal problems such as torsions, volvulus, & intussusception
- Traumatic injuries
- Problems associated with immobilization
- Infectious diseases
- Euthanasia for geriatric problems
- Euthanasia because of lameness
- Neuromuscular disorders
- Miscellaneous causes
(Wakefield, et al., 2006) (Boyd & Houpt, 1994) (Robert, 2005)
- Animal collectors Baron Friedrich von Falz-Fein, of Askaniya Nova, and first Duke of Bedford, Carl Hagenbeck to capture the newly discovered horses for their collections
- 53 Mongolian wild horses arrived in Europe between 1899 and 1902.
- Takhis purchased by Baron Falz-Fein produced 37 offspring. A few were given to western zoos, but the vast majority remained at Askanya Nova, where they all died during World War II.
- Only 26 animals survived in zoos, and of these only 11 were reproductive. A 12th founder could be imported from the wild in 1947.
- Creation of first studbook by Dr. Erna Mohr in 1957 based on her knowledge of animals in Berlin, Hamburg and Halle
- 228 animals in captivity between 1899 and 1958
- Studbook published annually after 1958 by Jiri Volf of Prague Zoo.
- Captive breeding programs exist in the U.S., Europe, and Asia, including Chinese and Mongolian breeding and reintroduction programs.
- ISIS Captive Population estimate
- Ataxia caused by degenerative myelopathy due to vitamin E deficiency
- Coccidiodomycosis cause of most deaths at Wild Animal Park
- Equine herpesvirus seen at several German zoos
- Infanticide is a concern among captive groups, and stallions may sometimes need to be separated from foals, particularly foals sired by other stallions
- Breeding is closely monitored to prevent inbreeding
- Tend to be more aggressive toward each other when moved into small enclosures
POPULATION AND CONSERVATION STATUS
(Boyd & Houpt 2004) (Boyd & King 2011) (Gato et al. 2011) (Wakefield 2006) (Ryder1993)(Moehlman 2005)
(Robert 2005) (Breining 2006) (Zimmerman 2005)
Causes Leading to Extinction in the Wild (Boyd & Houpt 2004) (Boyd & King 2011)
- Extensive hunting by Mongolians & Europeans in the 19th & 20th centuries.
- Early inter-breeding with Mongolian domestic horses and inbreeding resulted in impure bloodlines in captive populations.
- Cultural & political changes after WW II:
- Military activities
- Climatie change, harsh winters of 1945, 1948,1956
- Rarity of water holes in last remaining habitat
- Competition with livestock
- Land use pressure from humans
- Collecting trips by westerners
- Last recorded sightings in Dzungarian Gobi Desert, Mongolia 1969
- Causes of mortality among horses reintroduced in Mongolia
- Primary threat is hybridization with domestic horses plus competition with horses and other livestock for resources
- Infectiou s disease transmission from
- Equine piroplasmosis (a tick-transmitted disease endemic in the region
- Infection by Streptococcus equi which causes strangles, a highly contagious infection of lymph nodes and upper respiratory tract
- Wolf predation
- Illegal mining
- Other causes of mortality:
- Urolithiasis, pneumonia,
- Abortion and stillbirth.
Current Population Status
- In 2011, the species reassessed as Critically Endangered
(Population size estimated to number fewer than 250 mature individuals).
(Boyd & King 2011)
- One surviving mature individual remained in the wild
- Reintroduction eventually yeilded more than 50 mature individuals living in the wild since 2006
- IUCN classified as extinct in 1996
- 2004 Studbook lists more than 1500 animals in captivity (94 participating institutions)
- 60% of unique genes of the studbook population have been lost
- Main threats to captive population and reintroduction efforts are loss of founder genes & inbreeding depression.
- First International Symposium on the Preservation of the Przewalski’s Horse organized by Prague Zoo in 1959.
- More symposia in 1965, 1976, 1980, & 1990, 1999
- By 1979, there were 385 horses in 75 institutions in Europe North America and Cuba
- In 1979, North American breeders formed the first Species Survival Plan
- Cooperative breeding programs have now been adopted in Europe, Australasia and Russia,
- They manage about half of the global population and almost all of the surviving founder genes.
- Worthy of conservation efforts: genetically different from domestic horses and viable as a species
- Genetic sequences quite different from domestic horses (Goto et al. 2011; Orlando et al. 2013)
- No recent interbreeding between Przewalski's and domestic horses, according to comparison of complete genomic sequences (Orlando et al. 2013)
- Note: earlier study did suggest some interbreeding in ancient times (Goto et al. 2011)
- High level of genetic variation, similar to domestic horses, despite genetic "bottleneck" that caused severe reduction in numbers during the Ice Ages (Orlando et al. 2013)
- Definition: fenced area with natural vegetation, in which a small number of animals can be kept without supplemental feeding (Zimmerman 2005)
- U.K. – Eelmoor Marsh ( 66 ha - Marwell Zoo)
- Germany – Sprakel (68 ha – Cologne Zoo)
- Austria – Neusiedeler See (300 ha National Park – Tierpark, Schonbrunn, Wien)
- Hungary – Hortobagy: Named “Pentezug – (2,400 ha National Park – Cologne Zoo)
- France – Le Villaret: Swiss-born, behavioral ecologist, Claudia Feh acquired 11 horses from European zoos and established TAKH. Partners with WWF-France ( 55 horses)
- Ukraine – Askania Nova (2000 ha) and Chernobyl (207,000 ha) Ukraine Government
- Usbekistan – Bukhara (5,126 ha – Zoo Moscow)
- Kazakhstan - Altyn Emel (520,000 ha National Park – Munich and Nurnberg Zoos
- China – Gansu (6,700 ha) Munich Zoo
- Definition: program to re-establish a self-sustaining free-ranging population in an area that is part of an animal's historic range (Zimmerman 2005, 2011)
- Approximately 306 free-ranging reintroduced and native-born Przewalski’s horses in Mongolia as of 2011 (Zimmerman 2011)
- Mongolia – Hustain Nuruu (50,000 ha) Begun by Netherlands Govt. in Mongolia. Populated by takhis from the Dutch Foundation for the Preservation and Protection of the Przewalski Horse
- Mongolia – Gobi B (881,000 ha National Park) Begun by Mongolian Govt & Christian Oswald Foundation of Germany. Populated by takhis from Askania Nova, and Australia. Now supported by WAZA with takhi’s coming from 24 different institutions in 8 countries.
- Mongolia – Khomiin tal (25,000 ha National Park in Western Gobi) Station Biologique du Tour du Valat WWF
- China – Kalameili (1,700,000 ha) Begun with 18 horses from European and American Zoos – Cologne Zoo, EEP, Smithsonian Institution
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