Baboons are African and Arabian Old World monkeys belonging to the genus Papio, part of the subfamily Cercopithecinae. The five species are some of the largest nonhominoid members of the primate order; only the mandrill and the drill are larger. Previously, the closely related gelada (genus Theropithecus) and the two species (mandrill and drill) of genus Mandrillus were grouped in the same genus, and these Old World monkeys are still often referred to as baboons in everyday speech.
They range in size and weight depending on species. The Guinea baboon is 50 cm (20 in) and weighs only 14 kg (30 lb) while the largest chacma baboon can be 120 cm (47 in) and weigh 40 kg (90 lb). Five species of Papio are commonly recognized, although there is some disagreement about whether they are really full species or subspecies.
The traditional five-form classification probably under-represents the variation within Papio. Some commentators argue that at least two more forms should be recognized, including the tiny Kinda baboon (P. cynocephalus kindae) from Zambia, DR Congo, and Angola, and the gray-footed baboon (P. ursinus griseipes) found in Zambia, Botswana, Zimbabwe, Mozambique, and northern South Africa.
All baboons have long, dog-like muzzles, heavy, powerful jaws with sharp canine teeth, close-set eyes, thick fur except on their muzzles, short tails, and rough spots on their protruding buttocks, called ischial callosities. These calluses are nerveless, hairless pads of skin that provide for the sitting comfort of the baboon. All baboon species exhibit pronounced sexual dimorphism, usually in size, but also sometimes in colour or canine development. Males of the hamadryas baboon species also have large white manes.
Baboons are terrestrial (ground dwelling) and are found in open savannah, open woodland and hills across Africa. Their diets are omnivorous, but mostly herbivorous, yet they eat insects and occasionally prey on fish, shellfish, hares, birds, vervet monkeys, and small antelopes. They are foragers and are active at irregular times throughout the day and night. They can raid human dwellings, and in South Africa, they have been known to prey on sheep and goats.