Mandrillus is the genus of the mandrill and its close relative the drill. These two species are closely related to the baboons, and until recently were lumped together as a single species of baboon. Both Mandrillus species have long furrows on either side of their elongated snouts. The adult male mandrill's furrows are blue, while the furrows of the drill are black. Both species are terrestrial, living on the ground of the rainforests and occasionally grasslands of Central Africa.