Donkey
Donkeys can interbreed with other members of the family Equidae, and are commonly interbred with horses. The hybrid between a jack and a mare is a mule, valued as a working and riding animal in many countries. Some large donkey breeds such as the Asino di Martina Franca, the Baudet de Poitou and the Mammoth Jack are raised only for mule production. The hybrid between a stallion and a jenny is a hinny, and is less common. Like other inter-species hybrids, mules and hinnies are usually sterile. Donkeys can also breed with zebras in which the offspring is called a zonkey (among other names).
Onager
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 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: