onager (ŏnˈəjər) [key] or Persian wild ass, wild ass of central Asia, Equus hemonius onager. One of the several races of Asian wild ass ( E. hemonius ), it formerly ranged widely across S Russia, Iran, and Afghanistan. A small, slenderly built animal, it stands about 4 ft (120 cm) high at the shoulder. Its back and legs are rusty brown and its belly white. It has a black tail tuft, a short, stiff black mane, and a black spinal stripe lined with white on either side. For many centuries it was hunted for sport by the Persian nobility, and young onagers were captured for the breeding of riding animals. Owing to the swiftness and endurance of the onager, relatively few animals were captured by traditional methods. However, since the invention of modern firearms and automobiles, the animals have been extensively slaughtered for their flesh and hides. They survive in Russia only on the Badkhys reserve and are greatly reduced in numbers elsewhere. The continued existence of the race is in doubt. The onager is classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Perissodactyla, family Equidae.