Donkeys and mules may look and seem similar at first glance, but they are actually two fully separate animals. As such, there are a number of differences between the two.
To start with, donkeys are also a separate species from horses. Though they both belong to the equine family, donkeys are smaller, more compact and stockier than horses and have longer ears, coarser fur, and a thicker, shorter mane.
Donkeys, however, are very compatible with horses – so compatible, in fact, that they can breed together. When a male donkey breeds with a female horse, you get the mule.