Along with the pygmy chimp or bonobo (Pan paniscus), the chimpanzee is the closest living relative (4) to humans and is estimated to share 98 percent of our genes (6). There are currently four recognised subspecies of chimpanzee, showing differences in appearance and geographic range: the western or masked chimpanzee (Pan troglodytes verus), central or black-faced chimpanzee (P. t. troglodytes), eastern or long-haired chimpanzee (P. t. schweinfurthii) and the eastern Nigeria chimpanzee (P. t. vellerosus) (3). They all have the characteristic chimpanzee body shape with longer arms than legs, together with opposable thumbs and big toes (5). The bare skin on the face, ears, palms, and soles of the feet is pinkish to black (5), whilst the rest of the body is covered with brown to black hairs (6). Chimpanzees have very expressive features with their bulging eyebrows and protrusive lips (6). The long arms and fingers and mobile shoulder joints allow chimps to move easily in the trees where they forage and rest (4). The majority of their locomotion however, takes place on the ground in the form of 'knuckle-walking' (4).