Chimpanzees

 Infant chimpanzee in Uganda

Infant chimpanzee in Uganda

The scientific name for the chimpanzee is Pan troglodytes of which there are four subspecies: 

1. West African chimpanzee (Pan troglodytes verus).
2. Central chimpanzee (Pan troglodytes troglodytes). 
3. Eastern chimpanzee (Pan troglodytes schweinfurthii).
4. Nigeria-Cameroon chimpanzee (Pan troglodytes ellioti).

Chimpanzees live only in Africa and inhabit a wide range of African countries such as Gabon, Cameroon, Nigeria, Democratic Republic of Congo, Rwanda, Uganda, Tanzania, Ghana, Senegal, Angola and the Ivory Coast.

Evolutionary history

Chimpanzees belong to the Hominidae family that includes humans, bonobos, orangutans and gorillas. Chimpanzees, along with bonobos, were the last great ape species to split from the human branch of the Hominidae family about 5-6 million years ago. Chimpanzees, and bonobos, are the closest evolutionary relatives of humans. Chimpanzees are closely related to bonobos having split into separate species around 1 million years ago.

Habitat 

Chimpanzees are often found living in tropical rainforests, but they also inhabit drier regions such as savannahs. Chimpanzees make sleeping nests out of branches. They prefer sleeping in the trees when they are living in the rainforest whereas they often nest on the ground when living in savannahs. 

Diet

Mostly consists of fruit, seeds, flowers and leaves. They also eat meat, such as small monkeys and forest antelopes. Invertebrates, such as termites and ants, are also a favourite food source. 

Social Structure

 Male chimpanzee protecting his group's home range in Kibale Forest, Uganda

Male chimpanzee protecting his group's home range in Kibale Forest, Uganda

Chimpanzees live in large communities that sometimes have more than 100 members. Each community has a home range and males patrol and the protect the borders from incoming individuals of different communities. Within the chimpanzee community, subgroups are formed that travel independently around the home range. When subgroups return to the community, some of its members may leave to join other subgroups and/or new members will join the subgroup. This type of social dynamics within the chimpanzee community is often referred to as fission-fusion. 

A chimpanzee community is led by a single dominant alpha male who regularly displays his strength to other members, usually by drumming hard on tree trunks. This behaviour appears crucial for the alpha male to assert his dominance to other males who may otherwise challenge his leadership. The alpha male often has allies with high-ranking males within the group. These males will often support the alpha male during times of leadership challenges. Male dominance has many advantages, such as female mating privileges.

Like males, females within the group have a hierarchy. Dominant females have greater access to resources, such as food that has been obtained by male chimpanzees. Sometimes dominant females band together to support a high ranking male who is challenging the alpha male’s position. 

Reproduction

 Chimpanzee mother and her infant

Chimpanzee mother and her infant

Females usually have their first baby when they are 12-13 years old.  Pregnancy lasts around 8 months and the newborn is totally dependent on its mother and clings to her underbelly. After about six months the infant will sit on the mother’s back when travelling around.  Around 4 years of age, the infant is weaned and the mother becomes fertile again and usually pregnant soon afterwards.