Hamadryas Baboon

Characteristics

The papio genus of "savanna" baboons has five old-world baboons: Hamadryas, Anubis, Yellow, Chacma, and Guinea. The different species have varying coat colors but have a similar build. Males will generally have a mane or ruff. Both genders in baboon species have ischial callosities, forming padding for long periods of sitting and playing a role during reproduction. Social structures are complex and full of intricate behaviors. They are primarily fruit-eaters. These baboons are capable of interbreeding with each other.

Species Specifics

The hamadryas baboon is more dramatically sexually diamorphic in size than other old world monkeys. Both sexes are smaller than their other Papio counterparts. Males are gray-brown in color while the females are an olive-brown. Their color sets them apart from the other Papio baboons, as well as their northern range in Africa. The others are further south.

Physical Characteristics

Females reach adult size at 6 years of age. Males reach adult size at 10 years of age. Secondary male sex characteristics will not appear until after full size has been reached. These include the silver mane, white cheeks, and red/pink buttocks. Males will fully develop their testes before this, however, which indicates they may be secretly breeding without being the dominant male. Baboons' primary sense is their excellent vision. Their eyes are set closely together, giving them good depth perception for spotting predators and seeing other baboons' body language.

Ecology

Habitat

Hamadryas baboons are found in many kinds of habitats, provided there are sufficient watering holes and cliffs for sleeping. These includes subdesert, steppe, alpine grass meadows, and short-grass savannahs.

Distribution

A one-male unit may travel a few miles during daylight foraging for food but they will return to the same cliffs for sleeping.

Diet

Diet consists of mostly fruit, as well as grasses, insects, seeds, and flowers. Baboons have a unique ability to survive on a low quality diet when the habitat cannot provide anything more than grasses.

Ecological Web

Hamadryas baboons are a prey animal for hyena, leopards, and eagles.

Activity and Behavior

Activity Pattern

They spend the night on rocky cliffs, sometimes foraging miles during the day but returning to the cliffs to sleep. The mornings are spent with other families, sometimes hundreds of hamadryas baboons, playing, grooming, and chasing. The family units will then leave to forage separately. Before retiring for sleep, the families will engage in social grooming again.

Behavior

Hamadryas baboons have many kinds of communication, such as vocalizations, visual and tactile signals, and gestures. Grooming is an extremely important behavior. It effects bonds between individuals. Hamadryas baboons are unique in that the females groom the dominant male more often than the other females. This may help them keep their place in the hierarchy and keep him loyalty. The act of grooming also releases beta-endorphins which induce a very relaxed state. This can help to ease tensions within the family.

Social Behavior

Hamadryas baboons utilize a one-male unit. One adult male will mate with multiple females and be dominant over the other individuals. Males are related to each other and females move between groups. A family group will be one dominant male with four or five females and their offspring. Those groups will come together to travel and may form bands of up to 50 or 100 individuals. These bands often form with related dominant males bringing together their family units. To form an intial harem, a male may take a young female from her mother and finish raising her himself. This bonds the pair together very strongly. A male may also follow a harem and either breed with the females without the dominant male's notice or try to depose him through combat. However, often males will respect the relationship between the dominant male and the females in his family. Females leave their natal group between 1.5 and 3.5 years of age and have been seen to join groups that contain females they already know.

Reproductive Behavior

When there is a takeover by a new dominant male, females may go through a "deceptive" sexual cycle. They will appear to be fertile and will mate with the new dominant male. This places them in a high social rank and may protect their current offspring from the new male.

Offspring

At birth, the pelage is black. At six months of age, it turns olive-brown. The mother provides care for the first few months of life, as the offspring is unable to walk or eat solid food. Offspring are weaned at about 239 days. Other members of the group are interested in the offspring and may even be groomed by adults other than their mother.

Conservation

Status

The hamadryas baboon is listed as "Least Concern" by the IUCN and its population is increasing. This may be due to loss of predators and small-scale agriculture. CITES has this species listed on Appendix II and under the African Convention it is listed as a vermin.

Historical

In the past, huge numbers of Hamadryas baboons were taken from the wild for medical research. However, this is not done anymore and the population has rebounded. In ancient times they were present in Egypt but they are extinct now in that country.

Current Threats

Our Role

Oakland Zoo participates in the Species Survival Plan for Hamadryas baboons.