See S. C. Strum, Almost Human (1987).
The baboons are African Old World monkeys belonging to the genus Papio, part of the subfamily Cercopithecinae.. There are five species, which are some of the largest non-hominid members of the primate order; only the Mandrill and the Drill are larger. Previously, the closely related Gelada (genus Theropithecus) and two species of Mandrill and Drill (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 from and weight depending on species, the Guinea Baboon is 50 cm (20 inches) and weighs only 14 kg (30 lb) while the biggest Chacma Baboon can be 120 cm (47 inches) and weigh 40 kg (90 lb).
The traditional 5-form classification probably under-represents the variation within Papio. Some commentators would argue that at least two more forms should be recognized, including the very tiny Kinda Baboon (P. cynocephalus kindae) from Zambia, the DRC, and Angola, and the Gray-footed Baboon (P. ursinus griseipes) found in Zambia, Botswana, Zimbabwe, Mozambique, and northern South Africa. However, current knowledge of the morphological, genetic, and behavioral diversity within Papio is too poor to make any final, comprehensive judgments on baboon taxonomy.
All baboons have long dog-like muzzles, close-set eyes, heavy powerful jaws, thick fur except on their muzzle, a short tail and rough spots on their protruding hindquarters (buttocks), called ischial callosities. These callouses are nerveless, hairless pads of skin which are present to provide for the sitting comfort of the baboon.
Baboons are terrestrial (ground dwelling) and are found in open savannah, open woodland and hills across Africa. Their diet is omnivorous, but mostly vegetarian; 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.
Their principal predators are man and the leopard, although they are tough prey for a leopard and large males will often confront them by flashing their eyelids, showing their teeth by yawning, making gestures, and chasing after the intruder/predator.
Baboons in captivity have been known to live up to 45 years, while in the wild their life expectancy is about 30 years.
Most baboons live in hierarchical troops. Group sizes vary between 5 to 250 animals (often about 50 or so), depending on specific circumstances, especially species and time of year. The structure within the troop varies considerably between Hamadryas Baboons and the remaining species, sometimes collectively referred to as savanna baboons. The Hamadryas Baboon has very large groups comprised of many smaller harems (one male with four or so females), to which females from elsewhere in the troop are recruited while still too young to breed. The other baboon species have a more promiscuous structure with a strict dominance hierarchy based on the female matriline. The Hamadryas Baboon group will typically include a younger male, but he will not attempt to mate with the females unless the older male is removed.
Baboons can determine from vocal exchanges what the dominance relations are between individuals. When a confrontation occurs between different families or where a lower-ranking baboon takes the offensive, baboons show more interest in the exchange than exchanges between members of the same family or when a higher-ranking baboon takes the offensive. This is because confrontations between different families or rank challenges can have a wider impact on the whole troop than an internal conflict in a family or a baboon reinforcing its dominance.
The collective noun for baboons is commonly troop or congress, although flange is also becoming common. This unusual term originates from a Not the Nine O'Clock News comedy sketch entitled "Gerald The Intelligent Gorilla" where it was used for comic effect.
In the harems of the Hamadryas Baboons, the males jealously guard their females, to the point of grabbing and biting the females when they wander too far away. Despite this, some males will raid harems for females. In such situations it often comes to aggressive fights by the males. Visual threats are usually accompanied by these aggressive fights. This would include a quick flashing of the eyelids accompanied by a yawn to show off the teeth. Some males succeed in taking a female from another's harem. This is called a 'takeover'. In many species, infant baboons are taken by the males as hostages during fights.
Baboon mating behavior varies greatly depending on the social structure of the troop. In the mixed groups of savanna baboons, each male can mate with any female. The mating order among the males depends partially on their social ranking, and fights between males are not unusual.
There are however more subtle possibilities; in mixed groups males sometimes try to win the friendship of females. To garner this friendship, they may help groom the female, help care for her young, or supply them with food. The probability is high that those young are their offspring. Some females clearly prefer such friendly males as mates. However, males will also take infants during fights in order to protect themselves from harm.
A female initiates mating by presenting her swollen rump to the male. But 'presenting' can also be used as a submissive gesture and is observed in males as well. Females typically give birth every other year, usually to a single infant, after a six month gestation. The young baboon weighs approximately one kilogram and is colored black when they are born. The females tend to be the primary caretaker of the young, although several females will share the duties for all of their offspring.
After about one year, the young animals are weaned. They reach sexual maturity in five to eight years. Baboon males leave their birth group, usually before they reach sexual maturity, whereas females are 'philopatric' and stay in the same group their whole life.