Due to their physical characteristics, particularly at the shoulder, donkeys are slower and less powerful than horses, although they do have an initial turn of speed over a short distance. In the wild, donkeys live further spread out from each other than horses. Hence they have amazing voices, which can carry up to two miles, and of course their delightful ears which are bigger than horses' so they can more easily hear a distant neighbour. There are also feral donkeys living in places such as the Mohave desert, in the south-west USA, where they thrive. These are not truly wild animals, but descendants of domestic donkeys that have escaped or been set free.
Most domestic donkeys are in much the same height range.
We cannot be sure how man first come to cooperate with the donkey. However, due to their patience and persistence, donkeys found a very valid role as a surefooted pack animal and draught animal. The donkey has an ill-founded reputation for being stubborn and stupid. This almost certainly reflects their handlers' characteristics rather than their own. It was often the less successful tradesmen that had donkeys, because they could not afford to keep horses, which have more expensive needs.