The donkey or ass (Equus africanus asinus),is a domesticated member of the horse family, Equidae. The wild ancestor of the donkey is the African wild ass, E. africanus. The donkey has been used as a working animal for at least 5000 years. There are more than 40 million donkeys in the world, mostly in underdeveloped countries, where they are used principally as draught or pack animals. Working donkeys are often associated with those living at or below subsistence levels. Small numbers of donkeys are kept for breeding or as pets in developed countries.
A male donkey or ass is called a jack, a female a jenny or jennet; a young donkey is a foal. Jack donkeys are often used to mate with female horses to produce mules.
Asses were first domesticated around 3000 BC, probably in Egypt or Mesopotamia, and have spread around the world. They continue to fill important roles in many places today. While domesticated species are increasing in numbers, the African wild ass and another relative, the onager, are endangered. As beasts of burden and companions, asses and donkeys have worked together with humans for millennia.
Donkeys vary considerably in size, depending on breed and management. The height at the withers ranges from 7.3 to 15.3 hands (31 to 63 inches, 79 to 160 cm), and the weight from 80 to 480 kg (180 to 1,060 lb). Working donkeys in the poorest countries have a life expectancy of 12 to 15 years; in more prosperous countries, they may have a lifespan of 30 to 50 years.
Donkeys are adapted to marginal desert lands. Unlike wild and feral horses, wild donkeys in dry areas are solitary and do not form harems. Each adult donkey establishes a home range; breeding over a large area may be dominated by one jack. The loud call or bray of the donkey, which typically lasts for twenty seconds and can be heard for over three kilometers, may help keep in contact with other donkeys over the wide spaces of the desert. Donkeys have large ears, which may pick up more distant sounds, and may help cool the donkey’s blood. Donkeys can defend themselves by biting, striking with the front hooves or kicking with the hind legs.