The donkey or ass  is a domesticated member of the horse family, Equidae.

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.

A male donkey or ass is called a jack, a female a jenny or jennet a young donkey is a foal.

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 have a notorious reputation for stubbornness, but this has been attributed to a much stronger sense of self-preservation than exhibited by horses.

Likely based on a stronger prey instinct and a weaker connection with man, it is considerably more difficult to force or frighten a donkey into doing something it perceives to be dangerous for whatever reason. Once a person has earned their confidence they can be willing and companionable partners and very dependable in work.

Although formal studies of their behaviour and cognition are rather limited, donkeys appear to be quite intelligent, cautious, friendly, playful, and eager to learn.