Along with the pygmy chimp or bonobo (Pan paniscus), the common chimpanzee or robust chimpanzee (Pan troglodytes) is the closest living relative to humans and is estimated to share 98 percent of our genes. There are currently four recognized subspecies of chimpanzee. They all have the characteristic chimpanzee body shape with longer arms than legs, together with opposable thumbs and big toes. The bare skin on the face, ears, palms, and soles of the feet is pinkish to black, whilst the rest of the body is covered with brown to black hairs. Common chimpanzees have very expressive features with their bulging eyebrows and protrusive lips. The long arms and fingers and mobile shoulder joints allow chimps to move easily in the trees where they forage and rest. The majority of their locomotion however, takes place on the ground in the form of 'knuckle-walking. Male common chimpanzees stay in the same community for their entire life. Common chimpanzees are incredibly dexterous and use tools such as sticks and rocks to probe for ants and crack nuts.