Baboons vary in size and weight depending on the species. The smallest, theKinda baboon, is 50 cm (20 in) in length and weighs only 14 kg (31 lb), while the largest, thechacma baboon, is up to 120 cm (47 in) in length and weighs 40 kg (88 lb). All baboons have long, dog-like muzzles, heavy, powerful jaws with sharpcanine teeth, close-set eyes, thick fur except on their muzzles, short tails, and nerveless, hairless pads of skin on their protrudingbuttocks calledischial callosities that provide for sitting comfort. Malehamadryas baboons have large white manes. Baboons exhibitsexual dimorphism in size, colour and/or canine teeth development.
Baboons arediurnal andterrestrial, 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 areomnivorous and their diet consists of a variety of plants and animals. Their principal predators areNile crocodiles,leopards,lions andhyenas. Most baboons live in hierarchical troops containingharems. Baboons can determine from vocal exchanges what thedominance 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.
Taxonomy
Six species ofPapio are recognized,[3] although there is some disagreement about whether they are really fullspecies orsubspecies.[4]
Previously five species of baboon were recognised; theKinda baboon has gained support for its species status after phylogenetic studies of all members ofPapio.[18][19]Many authors distinguishP. hamadryas as a full species, but regard all the others as subspecies ofP. 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 ofPapio 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).[4][20][21]
Fossil record
In 2015 researchers found the oldest baboon fossil on record, dated at 2 million years old.[22]
All baboons have long, dog-like muzzles, heavy, powerful jaws with sharpcanine teeth, close-set eyes, thick fur except on their muzzles, short tails, and rough spots on their protrudingbuttocks, calledischial callosities. Thesecalluses are nerveless, hairless pads of skin that provide for the sitting comfort of the baboon.
Chacma baboon skullMale olive baboon showing his canines. Ngorongoro National Park, Tanzania, 2014.
All baboon species exhibit pronouncedsexual dimorphism, usually in size, but also sometimes in colour. Males have much larger upper canines compared to females and use them in threat displays. Males of the hamadryas baboon species also have large white manes.
Baboons areterrestrial (ground dwelling) and are found in open savannah, open woodland and hills across Africa. They areomnivorous, highly opportunistic feeders and will eat virtually anything, including grasses, roots, seeds, leaves, bark, fruits, fungus, insects, spiders, worms, fish,shellfish, rodents, birds,vervet monkeys, and smallantelopes.[24] They are foragers and are active at irregular times throughout the day and night. They often raid human dwellings, and in South Africa they break into homes and cars in search of food. Baboons will also raid farms, eating crops and preying on sheep, goats and poultry.
Predators
Other than humans,[24] the principal predators of baboons areleopards,lions, andspotted andstriped hyenas.[25] They are considered a difficult prey for the leopard, though, which is mostly a threat to young baboons. Large males will often confront them by flashing their eyelids, showing their teeth by yawning, making gestures, and chasing after the intruder/predator. Although they are not a prey species, baboons have been killed by theblack mamba snake. This usually occurs when a baboon accidentally rouses the snake.[26]
Baboons caught up a tree by Kalahari lions (1 of 3)
Baboons caught up a tree by Kalahari lions (2 of 3)
Baboons caught up a tree by Kalahari lions (3 of 3)
Social systems
A troop of baboons
Thecollective noun for baboons is "troop".[27] Most baboons live in hierarchical troops.Group sizes are typically around 50 animals, but can vary between 5 and 250, depending on species, location 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 baboons often appear in very large groups composed of many smaller harems (one male with four or so females), to which females from elsewhere in the troop are recruited while they are still too young to breed. Other baboon species have a more promiscuous structure with a strict dominance hierarchy based on thematriline. 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. 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. Such situations often cause aggressive fights between the males. Visual threats usually accompany these aggressive fights. These 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, called a "takeover". In several species, infant baboons are taken by the males as hostages, or used as shields during fights.
Baboons can determine from vocal exchanges what thedominance 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.[28]
Baboonsocial 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.[29]
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 her 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 to protect themselves from harm. A female initiates mating by presenting herswollen rump to the male's face.[30]
Females typically give birth after a six-month gestation, usually to a single infant; twin baboons are rare and often do not survive. The young baboon weighs approximately 400 g and has a black epidermis when 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 arephilopatric 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.
InEgyptian mythology,Babi was the deification of the hamadryas baboon and was therefore a sacred animal. It was known as the attendant ofThoth, so is also called the sacred baboon. The 2009 documentaryBaboon Woman examines the relationship between baboons and humans in South Africa.
Diseases
Herpesvirus papio family of viruses and strains infect baboons. Their effects on humans are unknown. Humans infected withMycobacterium tuberculosis can transmit the disease to the primates upon close proximity. Pathogens have a high likelihood of spreading through humans and species of nonhuman primates, such as baboons.[33]
^abNewman, T. K.; Jolly, C. J.; Rogers, J. (2004). "Mitochondrial phylogeny and systematics of baboons (Papio)".American Journal of Physical Anthropology.124 (1):17–27.doi:10.1002/ajpa.10340.PMID15085544.
^Frost, S. R.; Marcus, L. F.; Bookstein, F. L.; Reddy, D. P.; Delson, E. (2003). "Cranial allometry, phylogeography, and systematics of large-bodied papionins (Primates:Cercopithecinae) inferred from geometric morphometric analysis of landmark data".Anatomical Record.275 (2):1048–1072.doi:10.1002/ar.a.10112.PMID14613306.S2CID42411162.
^Wildman, D. E.; Bergman, T. J.; al-Aghbari, A.; Sterner, K. N.; Newman, T. K.; Phillips-Conroy, J. E.; Jolly, C. J.; Disotell, T. R. (2004). "Mitochondrial evidence for the origin of hamadryas baboons".Molecular Phylogenetics and Evolution.32 (1):287–296.Bibcode:2004MolPE..32..287W.doi:10.1016/j.ympev.2003.12.014.PMID15186814.
^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.
^Altmann, J.; Hausfater, G.; Altmann, S. A. (1988). "Determinants of reproductive success in savannah baboons,Papio cynocephalus". In Clutton-Brock T. H. (ed.).Reproductive success: studies of individual variation in contrasting breeding systems. Chicago (IL): University Chicago Press. pp. 403–418.
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