Cercocebus or white-eyelid mangabeys, is a genus of Old World monkeys. They are characterized by their bare upper eyelids which are lighter than their facial skin colouring, and the uniformly coloured hairs of the fur. The other two genera of mangabeys, Lophocebus and Rungwecebus, were once thought to be very closely related to Cercocebus, so much so that all the species were placed in one genus. However, it is now understood that Lophocebus and Rungwecebus species are more closely related to the baboons in genus Papio, while the Cercocebus species are more closely related to the mandrill.