Thickset and robust, but more lightly built than the gorilla, the chimpanzee has a strong body and long limbs, the powerful arms being longer than the legs. Its hands and feet are narrow and long, with opposable thumbs on the hands.
Males are slightly larger than females.
There is great variability in the color of hair and facial skin, but the hair is generally blackish and the face light, darkening in older individuals. The rounded head bears broad, prominent ears, and the lips are mobile and protrusible. Chimpanzees climb well but spend most of the time on the ground, where they generally walk on all fours, even though they stand erect on occasion, as when their hands are full of food. Their social structure is more variable than that of the gorilla. Rainforest animals live in troops of males, of females with young, of males and females with young, or of adults of both sexes without young.