Onager a subspecies of the onager as "E. hemionus kiang", but recent molecular studies indicate it to be a distinct species, having diverged from the closest relative of the Mongolian wild ass's ancestor less than 500,000 years ago. Widely five recognized subspecies of the onager include: A sixth possible subspecies, the Gobi khulan ("E. h. luteus", also called the "chigetai" or "dziggetai") has been proposed, but may be synonymous with "E. h. hemionus". Debates over the taxonomic identity of the onager occurred until 1980. As of today, four living subspecies and one extinct subspecies of the Asiatic wild ass have been
Onager seen feeding on seed pods such as "Prosopis" and breaking up woody vegetation with their hooves to get at more succulent herbs growing at the base of woody plants. During the winter, onagers also eat snow as a substitute for water. When natural water sources are unavailable, the onager digs holes in dry riverbeds to access subsurface water. The water holes dug by the onagers are often subsequently visited by domestic livestock, as well as other wild animals. Water is also found in the plants on which the onagers feed. During spring and summer in Mongolia, the succulent plants of