biology

Powerful jaw, the angle formed by upper and lower jaw is greater than in domestic horses. The hair of the erect mane is placed in three rows. Light colored (body color) bristly hair is lined up at each side of the longer dark hair of the mane.


Dark dorsal stripe from mane to tail tuft. Tail hair of graduated length, with light colored short guard hair in the upper third and two third of long dark hair. White muzzle White belly Body color ranges from light dun to dark dun, sometimes reddish Three to ten dark stripes can be present on the carpus or tarsus. They can also be of same color as the body with exception of a dark wreath around the hoof. Limbs can also be of dark color without perceptible stripes. During summer the pelage is short and smooth, during winter it becomes longer and lighter in color. Mane and the short guard hair of the tail are shed once a year in contrast to domestic horses.

Ecology and Habitat The former geographical range of the Przewalski’s horse was the Dzungarian Gobi which comprises the north of Xinjiang in China and the south west of Mongolia. This landscape is characterized by a continental climate. The Dzungarian basin is surrounded by the Mongolian Altai in the north east, in the south and south west by the Takhiin-Shar-Nuruu, Bogda-Shan and Tien-Shan and in the west by the Dzungarian Alatau and Tarbagatai mountains.

Deserts with shrub communities are predominant in the centre of this landscape. Oases of lush vegetation can be found within the desert zone. The periphery of the Dzungarian Gobi shows a greater variety of vegetation types: Steppe deserts with prevailing shrub communities (e. g. Tamarix, Haloxilon) or desert steppes with the typical feathergrass (Stipa spec.) and mountainous steppes, which are abundant in species. Saline sites with characteristic flora are distributed over the entire Dzungarian Gobi.
Przewalski’s horses have been mainly sighted at areas occupied by desert steppe, semi desert communities and at mountainous steppe regions. These ecosystems comprise a large spectrum of highly nutritious and vitamin rich plants, which are available throughout the year (Stipa gobica, Stipa glareosa, Anabasis brevifolia, Reaumuria, Artemisia, Allium species, Festuca vakesuaca). Dziggitais (Equus hemionus hemionus) also occupy this habitat, but they can also survive in steppe deserts of greater aridity. This ability saved them from extinction through human impact. Recent observations have also proved that Przewalski’s horses are primarily steppe herbivores, well adapted to the arid steppe of the Dzungarian Gobi (Zimmermann 1999). But they are also able to survive under arid conditions with extremely high temperatures (+40°C) as long as they have access to water (Van Dierendonck & de Vries 1996). Surface water resources in the Dzungarian Gobi are supplied by ground water. In some areas ground water arrives at the surface as springs. The climate of the Dzungarian Gobi is one of extremes with rapid changes in temperature. Przewalski’s horses cannot only cope with extreme heat but also with extreme cold (- 40°C) by acquiring strong subcutaneous fat deposits during summer. In winter horses lower their metabolism and reduce their subcutaneous temperature to 24°C in order to decrease heat dissipation (Kuntz 2005).

Social Behaviour Przewalski’s horses live in harem systems. One adult stallion defends a group of three to five mares and their progeny. These groups reside in home-ranges. These are areas which are roamed regularly. They must include sufficient water and food resources and optimal protection against extreme meteorological conditions. Przewalski’s horses avoid areas with great incidences of biting flies and mosquitoes


Allogrooming	The dominant stallion displays the foreleg kick, the yearling shows "snapping".

During winter groups of Przewalski’s horses come together by still maintaining minor distances. This is regarded as a defence strategy against wolves, their main predator. In general, only old individuals and foals fall prey to wolf packs. But a group of strong and healthy adult Przewalski’s horses can kill attackers with bites and powerful kicks of their hooves.

Social Systems, Mate Choice and Reproduction

	The Harem Harems include three to five mares, their offspring and one adult stallion. Foals can stay in these groups up to three years of age. Mares of one group built up relationships that can last a life long. Stallions reside in groups temporarily until they are defeated by another stronger stallion. Mares can conceive shortly after they have given birth. Thus infanticide (In general, killing of offspring by non-related male conspecifics) does not occur once a new stallion has taken over the harem.

Bachelors Young mares and stallions leave their family herds between ages one and three. They assemble in bachelor groups which undergo continuous changes through immigration and emigration. Young mares attach at a maximum age of three years to a strong five to seven year old stallion which, in general, had led a bachelor group beforehand. Young mares of one group are often kin and become the core of the newly established harem group. The remaining young stallions stay together for an extended period of time and initially exercise their skills in harmless play-fights which continuously become more serious. They achieve sexual maturity at the age of two, but still show deficiencies in physical and social strength and thus lack qualities that attract young mares or are required to challenge the leading stallion of a harem. Article Die Haltung von Junggesellengruppen für das EEP-Przewalskipferd – Hengste in Gehegen und ReservatenLydia Kolter und Waltraut Zimmermann
	Stallion after a fight
Mate Choice Waterholes are places where harem groups encounter bachelor groups. Young stallions seek for the opportunity to take over harems. Beside urine and faeces comment fights are a means to gather information about the competitor. Comment fights can easily escalate, especially those with both participants being of same strength and aiming at taking over or defending mares. They are combined with extreme risks and can result in severe injuries. Therefore maximum age of free ranging stallions seldom exceeds 12 to 15 years

Reproduction Przewalski’s horses are polyoestrus i.e. they have more than one period of oestrus per year. Gestation period is about 11 months. Body weight of foals after birth is about 25 kg. Immediately after delivery the mare stands up and thus tears off the umbilical cord and frees the foal carefully from the oolemma with her teeth. Within one hour the foal is able to stand on its own feet and searches for the mammary glands with assistance of the mare. In general, mares give birth within the group. But sometimes they leave the harem to give birth and return after a couple of days. Przewalski’s foals are weaned after about 6 months, but still stay with their mothers for one year. Young mares which have not yet left the family group often assist in taking care of foals. In dangerous situations they stay together with the offspring in the core of the group while the stronger and more experienced adult mares fight off non-familiar stallions or wolves

Is the Przewalski’s Horse the Ancestor of our Domestic Horse? Although hybridization results in fertile progeny, this question can be negated, because: The Przewalski’s horse lived remote from the domestication centre of the Near East and was probably even an endemic subspecies of the Dzungarian Gobi. The Przewalski’s horse shows 66 chromosomes in contrast to the domestic horse which only has 64 chromosomes. Newly developed techniques in genetic research might help to reveal the true ancestor or even a more complex background in the evolution of the modern horse.

Tarpan

The two extinct representatives of the wild horse Equus f. sylvaticus (Forest Tarpan) and Equus f. gmelini (Steppe Tarpan), were once distributed among forest - and grass steppes of central and eastern Europe. Reliable descriptions of phenotype are not existent, therefore back cross breeding lacks justification. It is also unknown if areas inhabited by Tarpan populations and Przewalski’s horses ever overlapped.

Suggested reading

Carrol, J., Murphy, C. J., Neitz, M., Ver Hoeve, J. M., Neitz, J. (2001):
Photopigment basis for dichromatic color vision in the horse. Journal of vision 1: 80-87

Hall, C. A., Cassaday,H. J., Derrington A. M. (2003):
The effect of stimulus height on visual discrimination in horses1. J. Anim. Sci.. 81:1715–1720

Kuntz, R. (2005):
Ausmaß und Ursachen des Energiehaushaltes bei Przewalskipferden (Equus ferus przewalskii). Dissertation. Universität Wien

Nobis, G. (1971):
Vom Wildpferd zum Hauspferd. Fundamenta. Monographien zur Urgeschichte. Boehlau Verlag, Köln.

Ryder, O. (1994):
Genetic Studies of Przewalski’s horses (Equus ferus przewalskii) and their impact on Conservation. In Przewalski’s horse: The History and Biology of an endangered Species (L. Boyd & D.A. Houpt eds.) pp. 75 – 92. State University of New York Press • Albany.

Timney, B. & Macuda, T. (2001):
Vision and hearing in horses. Journal of American Veterinary Medical Association Vol. 218 (10)

Van Dierendonck, M. & Wallis de Vries, M. F. (1996):
Ungulate Reintroductions: Experiences with Takhis or Przewalski’s horses (Equus ferus przewalskii) in Mongolia. Conservation Biology 10 (3): 728 – 740

Wakefield, S., Knowles, J., Zimmermann, W., Van Dierendonck, M.. (2002):
Status and Action Plan for the Przewalski’s horse (Equus ferus przewalskii). In Equids: Zebras, Asses and Horses. Status Survey and Conservation Action Plan (P. D. Moehlman ed.) pp. 82 – 92

Wallner, B., Brem, G., Muller, M. and Achmann, R. (2003):
Fixed nucleotide differences on the Y chromosome indicate clear divergence between Equus przewalskii and Equus caballus. Animal Genetics 34: 453 – 456

Zimmermann, W. (1999):
Feasibility study, site selection and development of a Reintroduction Project of the Przewalski’s Horse (Equus ferus przewalskii) in the Dzuungari Gobi in Mongolia. In Europäische Landschaftsentwicklung mit Grossen Weidetieren – Geschichte, Modelle und Perspektiven. Natur- und Kulturlandschaft (B. Gerken und M. Görner eds.). Höxter / Jena 3: 322 – 331

Species:	Equus ferus, wild horse
Subspecies:	Equus ferus przewalskii

Phenotype of the Przewalski’s horse

Stout body and stocky limbs.