Chimpanzee

Physical Characteristics

Noisy and curious, intelligent and social, the chimpanzee is the mammal most like a human. Chimpanzees fascinate humans and are favorites both in zoos and the wild.

In East Africa the chimpanzee is found in the wild in Tanzania and Uganda, but only in captivity in Kenya. Gombe National Park in Tanzania is the first park in Africa specifically created for chimpanzees.

The chimpanzee has a thickset body with long arms, short legs and no tail. Much of the body is covered with long black hair, but the face, ears, fingers and toes are bare. They have hands that can grip firmly, allowing them to pick up objects. The discovery that they used "tools" for certain purposes surprised the world.

Habitat

Chimps are mainly found in rain forests and wet savannas. While they spend equal time on land and in trees, they do most of their feeding and sleeping in trees.

Behavior

Chimps live in loose communities which can number anywhere from 10 to over 100 individuals. The entire troop may never assemble all together, but they share a home range which is fiercely protected from intruders. Community members forage by themselves or in small groups that are all male, all female or mixed. Female chimpanzees emigrate when they reach adolescence. Since a community’s female members are mostly unrelated they do not associate closely and are not even necessarily on friendly terms. Males, however, share blood ties and often cooperate. Mothers and male offspring also maintain ties that can last throughout their lives.

Chimps are incredibly vocal and use a complicated system of sounds to communicate with each other. They hoot, scream, grunt and drum on hollow trees with the flat of their hands, sometimes for hours. The discovery that chimpanzees used "tools" surprised the world. Their use of sticks to collect ants and termites from their nests and rocks to smash open nuts gave scientists proof that not only humans use cognitive thinking to problem-solve.

The female chimp has an estrus cycle of about 34 to 35 days. While in heat, the bare skin on her bottom becomes pink and swollen, and she may mate with several males. She normally gives birth to just one baby, which clings tightly to her breast and, like a human baby, develops rather slowly. An infant can sit up at 5 months and stand with support at 6 months. It is still suckled and sleeps with its mother until about 3 years of age, finally becoming independent and separating from her at about 4 years. Sexual maturity is reached between 8 and 10 years.

Chimps touch each other a great deal and may kiss when they meet. They also hold hands and groom each other. An adult chimp often has a special "friend" or companion with which it spends a lot of time. Female chimps give their young a great deal of attention and help each other with babysitting chores. Older chimps in the group are usually quite patient with energetic youngsters.

Diet

Chimps are diurnal (but often active on moonlit nights) and begin their activities at dawn. After descending from their night nests they hungrily feed on fruits, their principal diet, and on leaves, buds and blossoms. After a while their feeding becomes more selective, and they will choose only the ripest fruit. They usually pick fruit with their hands, but they eat berries and seeds directly off the stem with their lips. Their diet consists of up to 80 different plant foods.

Predators and Threats

The number of chimps in the wild is steadily decreasing. The wilderness areas necessary to their survival are disappearing at an alarming rate as more forests are cut down for farming and other activities. As the human's closest relative the chimp is vulnerable to many of the same diseases, and their capture for medical research contributes to their decline, especially in West Africa. as more forests are cut down for farm activities. In addition, recent outbreaks of the incurable disease Ebola hemorrhagic fever, threaten to decimate important chimpanzee populations in the Republic of Congo and Gabon.

Did You Know?

• Chimpanzees use large sticks and branches as clubs or throw them at enemies like leopards and humans.

How can we assess chimp intelligence?

• they make tools and use them to acquire foods, for social displays, etc
• they have sophisticated hunting strategies that require cooperation, and allow animals to achieve influence and rank by sharing meat
• they are highly status conscious and manipulative, capable of deception
• they are analytical and problem-solvers, clearly capable of insight and complex "cognitive performance" in both the wild and in captivity, and particularly adept at analyzing relative relationships
• language experiments have shown that chimps are creative, can learn to use symbols (and teach them to others) and understand aspects of human language including some relational syntax, concepts of number and numerical sequence