Mule is the offspring of a male donkey and a female horse. Horse and donkeys are different species but most mules are sterile.
The size of a mule and work to which it is put depend largely on the breeding of the mule's dam . Mules can be lightweight, medium weight, or even, when produced from draft horse mares, of moderately heavy weight.
Mules are "more patient, sure-footed, hardy and long-lived than horses, and they are considered less obstinate, faster, and more intelligent than donkeys.
Mules were used in the military. Used as a vehicle to carry supplies in forests and other animals can not enter. I like to mules because it's cute and strong , I would like to ride it.