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Baboons are comprising the biology Papio, one of the 23 genera of Old World monkeys, in the family Cercopithecidae. There are six species of baboon: the hamadryas baboon, the Guinea baboon, the olive baboon, the yellow baboon, the Kinda baboon and the chacma baboon. Each species is native to one of six areas of Africa and the hamadryas baboon is also native to part of the Arabian Peninsula. Baboons are among the largest non-hominoid primates and have existed for at least two million years.
Baboons vary in size and weight depending on the species. The smallest, the Kinda baboon, is in length and weighs only , while the largest, the chacma baboon, is up to in length and weighs . 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 nerveless, hairless pads of skin on their protruding buttocks called callosity that provide for sitting comfort. Male have large white manes. Baboons exhibit sexual dimorphism in size, colour and/or canine teeth development.
Baboons are diurnality and terrestrial, but sleep in trees, or on high cliffs or rocks at night, away from predators. They are found in open savannas and woodlands across Africa. They are omnivore and their diet consists of a variety of plants and animals. Their principal predators are , leopards, lions and . Most baboons live in hierarchical troops containing harems. Baboons can determine from vocal exchanges what the dominance relations are between individuals.
In general, each male can mate with any female; the mating order among the males depends partly on their social rank. Females typically give birth after a six-month gestation, usually to one infant. The females tend to be the primary caretaker of the young, although several females may share the duties for all of their offspring. Offspring are weaned after about a year. They reach sexual maturity around five to eight years. Males leave their birth group, usually before they reach sexual maturity, whereas most females stay in the same group for their lives. Baboons in captivity live up to 45 years, while in the wild they average between 20 and 30 years.
Previously five species of baboon were recognised; the Kinda baboon has gained support for its species status after phylogenetic studies of all members of Papio. Many authors distinguish P. hamadryas as a full species, but regard all the others as subspecies of P. cynocephalus and refer to them collectively as "savanna baboons". This may not be helpful: it is based on the argument that the hamadryas baboon is behaviorally and physically distinct from other baboon species, and that this reflects a separate evolutionary history. However, recent morphological and genetic studies of Papio show the hamadryas baboon to be more closely related to the northern baboon species (the Guinea and olive baboons) than to the southern species (the yellow and chacma baboons).
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 this exchange than those 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.
Baboon social dynamics can also vary; Robert Sapolsky reported on a troop, known as the Forest Troop, during the 1980s, which experienced significantly less aggressive social dynamics after its most aggressive males died off during a tuberculosis outbreak, leaving a skewed gender ratio of majority females and a minority of low-aggression males. This relatively low-aggression culture persisted into the 1990s and extended to new males coming into the troop, though Sapolsky observed that while unique, the troop was not an "unrecognizably different utopia"; there was still a dominance hierarchy and aggressive intrasexual competition amongst males. Furthermore, no new behaviours were created amongst the baboons, rather the difference was the frequency and context of existing baboon behaviour.Fry, Douglas P., ed. War, peace, and human nature: the convergence of evolutionary and cultural views. Oxford University Press, 2013, pp.427-436. Sapolsky questioned if the Forest Troop would be able to maintain its social system if a large number of aggressive new males joined. However, he notes that there was never an opportunity to study this as by the 2000s, the Forest Troop had expanded its range and individual animals spend most of their time alone. This means that the troop has essentially fragmented and no longer functions as a cohesive social unit.
In a wild baboon population of the Amboseli ecosystem in Kenya, inbreeding is avoided by mate choice. Inbreeding avoidance through mate choice is thought to only evolve when related possible sexual partners frequently encounter each other and there is a risk of inbreeding depression.
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 philopatry and stay in the same group their whole lives.
Baboons in captivity have been known to live up to 45 years, while in the wild their life expectancy is between 20 and 30 years.
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