The chimpanzee (Pan troglodytes) is a species of great ape native to the forests and savannahs of tropical Africa. The chimpanzee is covered in coarse black hair, but has a bare face, fingers, toes, palms of the hands, and soles of the feet. The chimpanzee, along with the pygmy chimpanzee or bonobo, is the closest living relative of humans. Chimps sleep in trees, but forage mainly on the ground during the day, using ‘knuckle-walking’ to move around. It is also known as the common chimpanzee, robust chimpanzee, or simply "chimp"