mule, hybrid offspring of a male donkey (see ass) and a female horse, bred as a work animal. The name is also sometimes applied to the hinny, the offspring of a male horse and female donkey; hinnies are considered inferior to mules. The mule has many donkey characteristics—long ears, a tufted tail, slender legs, small hooves, and a loud bray—but it resembles a horse in size and strength. Most mules weigh from 1,100 to 1,400 lb (500–640 kg). They lack the speed of horses, but are more surefooted and have great powers of endurance. Like donkeys, they are of a cautious and temperamental disposition and require expert handling to perform well. Both sexes are sterile. Mules have been bred as pack and draft animals since prehistoric times, and are still used throughout the world, particularly in regions where mechanized farm equipment is uncommon. They have been widely used in the United States, where they were first bred by George Washington, but are now found mainly in the southeastern states. Mules were used extensively for military transport before the advent of mechanization. They are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Perissodactyla, family Equidae.
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