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 study 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 Onsager 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.

Wild donkeys have adapted to living in near desert environments and because of this, donkeys have very hardy immune and digestive systems. This allows the donkey to be able to process and gain nutrition from vegetation that many other species of Animal have great difficulty gaining any nutrition from.

There are thought to be more than 44 million donkeys found throughout the world, with around 11 million of these donkeys found in China. Scientists believe that the real number of donkeys could be much higher than this as many donkeys go unaccounted for.

Donkeys are said to have a relatively stubborn temperament but once the owner of the donkey has gained the donkeys trust, the donkey is extremely loyal and a good friend. Donkeys are not truly stubborn; they are very good at taking care of themselves. Their self-preservation instincts are strong. They will refuse to proceed if they sense danger or if they are overburdened. They pass this valuable trait on to the mule. Donkeys are also thought to have a calming affect over distressed horses and donkeys are often put into fields with horses as they make great companions for them.