Donkey

Donkeys were supposedly domesticated around 5000 years ago in the north east of Africa  from the Somali wild ass. The domestication if donkeys soon spread across the globe, with people mainly using the donkeys to help carry heavy loads and transport goods long distances. They are anatomically normal and show normal breeding behavior, so hybrids should be gelded as early as possible to avoid studdy behavior.

The majority of donkeys today still do the same burdening tasks that the donkeys did thousands of years ago, in a similar way to the pack-mules in the Asian mountains that transport burdening goods through the mountain passes.

Despite the obvious similarities between a donkey and a horse, a donkey-horse offspring (mule) will always be infertile, due to a genetic malfunction that occurs when two different species mate. This is also the case when different species of asses interbreed, such as the onager and the Somali wild ass. Even though they are in the same genus taxonomically, the hybrid offspring of two species of ass will have sterile offspring.