TABLE OF CONTENTS - National Zoo

PERSIAN ONAGER
(Equus hemionus onager)
Herbivore
Description: The onager, or wild ass, has a general body form that is thick headed,
short legged, and stocky. They are tawny colored. The tail is moderately long, with
the hairs reaching at least to the middle of the leg when the tail is hanging down.
Their bodies are heavily haired with a mane on the neck and a lock of hair on their
forehead, known as the forelock.
Teeth: The onager has three pairs of incisors and 0-1 pair of canines in both the
upper and lower jaws. The incisors are shaped like chisels, the enamel on the tips
folding inward to form a pit, or “mark,” that is worn off in early life. The cheek teeth
have a complex structure. They are high crowned, with four main columns and
various infoldings with much cement. They have 3-4 pairs of premolars in the upper
jaw and three pairs of premolars in the lower jaw. They also have three pairs of
molars in both jaws, for a total of 36-42 teeth.
Diet: Onagers are entirely vegetarian in habit, feeding mainly on grass, although
some browsing in the low branches of trees and shrubs is done. They drink water
daily; however, onagers can go for longer periods without water than can any other
species of equid, and they are remarkably capable of surviving on a minimum of food
and under hot and difficult conditions.
Range: They are located in the desert and dry steppe zone from Syria and Iraq to
Manchuria and western India.
Habitat: The onager is found mostly in desert plains, sparsely covered with low
shrub.
Social Organization: Members of this species live in unstable groups of variable
composition, and there is no indication of permanent bonds between any adult
individuals.
Conservation Status: The wild asses of Asia have declined drastically though such
factors as excessive hunting, habitat deterioration, transmission of disease from
livestock, and interbreeding with the domestic donkey.
Source: Nowak, Ronald M. and John L. Paradiso. Walker’s Mammals of the World.
4th edition, Volume II. Baltimore, MD: The Johns Hopkins University Press, 1983.
Pages 1157-1163.
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