Chimpanzees are covered in thin but long black body hair, except for the face, hands, and feet, which may have pink or black skin. They normally walk on all fours, supporting the front of the body on the knuckles of the fingers, but can stand or walk upright for a short distance. They are strong and climb well, but spend time on the ground, living in loose social groups. The bulk of the diet is fruit, with some leaves, insects, and occasional meat. Chimpanzees give birth to a single infant approximately every five years.
Chimpanzees can use 'tools', fashioning twigs to extract termites from their nests.
According to a 1998 estimate by the Worldwide Fund for Nature, the world population of chimpanzees stands at 200,000. Bonobos are about the same height as 'common' chimpanzees, but they are of a slighter build, with less hair, and stand upright more frequently. They are a distinct species, numbering approximately 10,000. Chimpanzees are found in an area from West Africa to western Uganda and Tanzania in the east. Trained chimpanzees can learn to communicate with humans with the aid of machines or sign language, but are probably precluded from human speech by the position of the voicebox.