Regarded as our closest surviving relatives, chimpanzees stand up to 170 cm (67 in) tall on their hind legs. They live in groups, largely on the ground.
These intelligent, social animals are very closely related to human beings, and give us some indication of the kind of animal from which we evolved. Chimpanzees have a number of characteristics that were once thought to be exclusively human. For example, they construct tools - tasks that few other species, except humans and orang-utans, are capable of. One tool used by chimps is a probe, made of a twig stripped of leaves. It is poked into termite nests to extract these insects, which are then eaten.
Chimpanzees live in groups comprising 15 - 80 animals, which have complex social structures. The dominant males are not necessarily the strongest individuals, but the ones best able to recruit the most allies. Chimps are territorial, and neighbouring groups are aggressive towards one another. Indeed, chimps share an unpleasant characteristic with humans: they go to war, and sometimes individuals of one group will hunt and kill members of rival groups.
Chimpanzees are tool-users, and they are also skilled at communication, which they do with vocalizations and facial expressions.
Studies of chimpanzees have revealed that they consume various plants that may have medical properties in treating ailments, from parasites to tumours. These can be identified by the way in which the chimps eat them, which is different to how they eat their normal food: they may seek out specific plants when needed, and swallow their leaves without chewing them.
Distribution: Found in central Africa, in areas of tropical forest and ranging from the Gambia across to the Congo and eastwards to Uganda.
Habitat: Tropical forest and woody savannah.
Weight: 26 - 70 kg (57 - 154 lb); males are larger
Length: 64 - 93 cm (25 - 37 in)
Maturity: 13 - 15 years for both sexes
Gestation Period: About 230 days
Breeding: 1, rarely twins weaning occurs at 3.5 - 4.5 years
Diet: Feeds mainly on fruit although also eats flowers, roots and some invertebrates; may also catch small mammals and reptiles.
Lifespan: Up to 60 years.
The skin of chimpanzees darkens with age, although their hair often becomes greyish over the back.
The long fingers can be curled into the hand when the chimpanzee is walking on the ground.
Chimpanzees are noisy. Their calls indicate their moods and keep members of the group in touch with each other.
Young chimpanzees playing together; they are able to laugh like humans.