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WILDLIFE: MAMMALS: OLIVE BABOON
Genus and species: Papio anubis¹
English: Olive baboon, Anubis
¹ Some authors consider olive and yellow baboons as two subspecies of Papio cynocephalus, P. c. anubis and P. c. cynocephalus
Body: large and thick, with shoulders higher than rump. Colour greyish brown-olive. Hair well developed around shoulders and neck, building a mantle in adult males that does not remarkably stand out from the body coat. Tail has a "broken" look, hanging in an acute angle towards the ground from an erect base. Hands and feet naked and blackish. Callosities naked and well-developed in rump, grey purple in colour. Females smaller than males. Length: 60-70 cm. Tail: 45 cm. Height: 50-70 cm. Weight: males 27-45 kg, females 14-20 kg.
Head: elongated profile, dog-like. Naked and protuberant muzzle, blackish, with nasal fossae in the tip. Naked ears of the same colour as muzzle. Small eyes, deep and close under a prominent supraorbital arch. Whitish eyelids. Males show long and sharp canines up to 5 cm in length.
Distribution and ecology
Distributed throughout the country except in eastern regions, where it is replaced by the yellow baboon. Inhabits a great variety of habitats, from open forest to sub-desert regions: bush in stone lands, savannah, acacia light forests and wooded plains, rocky outcrops and even lava flows. In mountains it can be found up to 3000 m. Though it obtains part of the water it needs from food and dew, it usually requires water sources at hand.
It feeds on every type of vegetal matter: grass, leaves, seeds, buds, stalks, berries, nuts, bulbs, water plants, flowers, bark, sap, fruits (figs, pods), roots, rhizomes, tubercles, fungi and lichens. Grass is the main diet, whereas rhizomes and tubercles predominate in the dry season. Large troops sometimes devastate crops. Baboons complement their diet with some animal food: locusts, grasshoppers, spiders, scorpions, worms, caterpillars, lizards and ants. They frequently pull ant-galls off Acacia drepanolobium trees. They can occasionally prey on eggs and chicks of ground-nesting birds, as well as on hares, small rodents, and even antelope calves. Baboons are inefficient killers, reason why they generally do not stalk prey but rather benefit from casual encounters and animals that conceal themselves when attacked, such as gazelle youngs. Finally, some cases of cannibalism have been recorded.
Diurnal and terrestrial, though it also climbs trees, specially for sleeping. Highly social. Lives in troops of 40-80 individuals, sometimes reaching 200. The size of groups varies according to food availability and environmental conditions, being larger where vegetation is thicker. Groups may temporarily break into smaller ones, but they are very stable units with a well-defined and complex social structure.
Each troop consists of family units. Families are hierarchized among them, so that even a female from a low rank family must subordinate to the youngs of a higher rank family. Inside each family, the mother has the dominant role, followed by her youngest son. A male may associate with a female and thus become a "godfather" for her offspring during their first two years of life, even if the male is not the actual father. Should the mother die, the godfather may assume the role of stepfather.
It is the females who really maintain the troop's cohesion, since males usually transfer from one troop to another. When they are 4 years old, males enter adolescence, develop their powerful canines and outgrow females in size and dominance. Males then usually emigrate to other troops, which helps to prevent inbreeding.
Communication plays an essential role in the troop's social organization. Grooming strengthens relationships among individuals, and auditive communication is based on a wide range of vocalizations. Baboons have excellent sight and smell, and are able to distinguish colours.
Baboons feed in the early morning and late evening, resting in a shaded place during the hottest hours. They sleep on top of trees, mainly acacias, or otherwise in rocky shelters, switching place every few days. When the troop rests or eats, the most dominant males and females with their offspring occupy the central positions and have preferential access to food sources. They are surrounded by less dominant males, estrous or pregnant females and juvenile groups. When the troop moves, less dominant males march in the first place, followed by females and youngs, adult dominant males and females with their progeny, and finally sub-adults. In a daytime, the troop can travel up to 11 km, covering a surface that reaches 25 km² in open plains.
Territories of different troops may overlap, but the central core, which includes water and food sources, resting places and trees for sleeping, is rarely invaded by another troop. During the dry season, different troops may reside around a waterhole without any conflict outbreaks.
Their main predators are leopards, lions, hunting dogs, crocodiles, hyenas, jackals, great eagles and python snakes. However, killers usually avoid facing the troop, since the baboon's defensive reaction is very aggressive. When an individual detects a predator, it barks loudly and the most dominant males rush to protect the group. Their sharp canines may inflict severe wounds to their attackers. When they meet humans, baboons usually flee by land, contrary to other monkeys. On the other hand, a human intrusion while baboons sleep up a tree is usually received with a dung rain. Baboon's longevity is 10-20 years.
Females are receptive for a week each month. They mate first with less dominant males, then with the rulers. They attract males exhibiting callosities in their rumps and the sexual tumefaction area between the vulva and the perineum. The most dominant females mate more frequently and their offspring have a higher survival rate. One female may associate with a male for several days, while the mating period lasts, but there are no harems.
After 6 months of gestation, the female gives birth to one infant, rarely two. Parturition usually takes place by night. Youngs have black hair, while face and rump are bright pink. During the first weeks, the mother carries her infant hanging under her belly, but from the sixth week on, the youngster usually climbs to the mother's back. At the age of 3 months, infants gather in play groups under close surveillance by their mothers. Though they are not weaned until the eighth month, young baboons start seeking their own food from the fifth month. They remain in close contact with their mother for the first one and a half years.
Yellow baboon (Papio cynocephalus): it can be distinguished from the olive baboon by its lighter body, with longer and more slender limbs. Its coat is fair yellow-brown, with whitish underparts. Adult males lack the mantle characteristic in olive baboons. Shorter muzzle profile. Length: 116-137 cm. Tail: 46-51 cm. Inhabits shrub, woodlands and rocky outcrops in East Kenya, including Amboseli and Tsavo parks.