Baboon

Baboons are a genus of Old World monkeys called *Papio*, one of 23 such genera in the family Cercopithecidae. They rank among the largest primates that aren't apes or humans, and their lineage stretches back at least two million years. There are six species: the hamadryas, Guinea, olive, yellow, Kinda, and chacma baboons. Each species is native to a different part of Africa, and the hamadryas also lives in a portion of the Arabian Peninsula.

Size and weight vary by species. The smallest is the Kinda baboon, measuring about 50 cm (20 in) long and weighing 14 kg (31 lb). The largest is the chacma baboon, reaching up to 120 cm (47 in) in length and 40 kg (88 lb). All baboons have long, dog-like muzzles, powerful jaws with sharp canine teeth, eyes set close together, thick fur (except on the muzzle), short tails, and bare, nerveless pads on their protruding buttocks called ischial callosities, which make sitting more comfortable. Male hamadryas baboons also have large white manes. The species show clear sexual dimorphism in size, color, and the development of their canine teeth.

Baboons are active during the day and live on the ground, but they sleep in trees or on high cliffs and rocks at night to avoid predators. They inhabit open savannas and woodlands across Africa. Their diet is omnivorous, including a wide range of plants and animals. Their main predators are Nile crocodiles, leopards, lions, and hyenas. Most baboons live in hierarchical troops that contain harems. They can figure out the dominance relationships between individuals just by listening to their vocal exchanges.

Generally, any male can mate with any female, and the order in which males mate depends partly on their social rank. After a gestation of about six months, females usually give birth to a single infant. Females are the primary caretakers of the young, though several females may share the duties for all their offspring. Young are weaned after about a year and reach sexual maturity between five and eight years old. Males leave their birth group, usually before reaching sexual maturity, while most females stay in the same group for life. In captivity, baboons can live up to 45 years; in the wild, they average between 20 and 30 years.

**Taxonomy** Six species of *Papio* are recognized, though there is some debate over whether they are true species or just subspecies. Previously, only five species were recognized; the Kinda baboon gained support as a distinct species after phylogenetic studies of all members of *Papio*. Many authors treat *P. hamadryas* as a full species but consider the others subspecies of *P. cynocephalus*, collectively calling them "savanna baboons." This classification may be misleading: it is based on the idea that the hamadryas baboon is behaviorally and physically distinct, reflecting a separate evolutionary history. However, recent morphological and genetic studies show the hamadryas baboon is more closely related to the northern species (Guinea and olive baboons) than to the southern ones (yellow and chacma baboons).

**Fossil Record** In 2015, researchers found the oldest baboon fossil on record, dated to 2 million years ago.

**Characteristics** All baboons have long, canine-like muzzles, heavy jaws with sharp canine teeth, close-set eyes, thick fur except on the muzzle, short tails, and rough, hairless pads on their protruding buttocks called ischial callosities. These calluses are nerveless and provide comfort when sitting. All species show pronounced sexual dimorphism, usually in size and sometimes in color. Males have much larger upper canines than females and use them to threaten or intimidate other baboons and predators. Male hamadryas baboons also have large white manes.

**Behavior and Ecology**

*Habitat and Prey* Baboons are ground-dwelling and live in open savannah, open woodland, and hills across Africa. They are omnivorous, highly opportunistic feeders that eat almost anything: grasses, roots, seeds, leaves, bark, fruits, fungus, insects, spiders, worms, fish, shellfish, rodents, birds, vervet monkeys, and small antelopes. They forage at irregular times throughout the day and night. They often raid human dwellings, and in South Africa they break into homes and cars for food. They also raid farms, eating crops and preying on sheep, goats, and poultry.

*Predators* Besides humans, their main predators are leopards, lions, and spotted and striped hyenas. Baboons are considered difficult prey for leopards, which mostly threaten young baboons. Large males often confront predators by flashing their eyelids, showing their teeth by yawning, making gestures, and chasing the intruder. Although not a typical prey species, baboons have been killed by black mamba snakes, usually when a baboon accidentally disturbs the snake.

**Social Systems** The collective noun for baboons is "troop." Most baboons live in hierarchical troops. Group sizes are typically around 50 animals but can range from 5 to 250, depending on species, location, and time of year. The structure within the troop varies considerably between hamadryas baboons and the other species (sometimes called savanna baboons). Hamadryas baboons often appear in very large groups made up of many smaller harems (one male with about four females), to which females from elsewhere in the troop are recruited while still too young to breed. Other baboon species have a more promiscuous structure with a strict dominance hierarchy based on the matriline. A hamadryas baboon group will typically include a younger male, but he will not attempt to mate with the females.