Donkey have worked together with humans for millennia. Traditionally, the scientific name for the donkey is "Equus asinus asinus" based on the principle of priority used for scientific names of animals. However, the International Commission on Zoological Nomenclature ruled in 2003 that if the domestic species and the wild species are considered subspecies of one another, the scientific name of the wild species has priority, even when that subspecies was described after the domestic subspecies. This means that the proper scientific name for the donkey is "Equus africanus asinus" when it is considered a subspecies, and "Equus asinus" when it is
Onager known as the Persian onager. Until this day, the species share the same name, "onager". The onager is a member of the subgenus "Asinus", belonging to the genus "Equus" and is classified under the family Equidae. The species was described and given its binomial name "Equus hemionus" by German zoologist Peter Simon Pallas in 1775. The Asiatic wild ass, among Old World equids, existed for more than 4 million years. The oldest divergence of "Equus" was the onager followed by the zebras and onwards. A new species called the kiang ("E. kiang"), a Tibetan relative, was previously considered to be