The black-crested mangabey is a highly arboreal primate, but does make use of all levels of the forest, from the ground to the highest branches of trees. Very distinguishable from other mangabey species because of the black hair crest on top of the head, these charismatic monkey also has grey cheek hairs curved outwards. The waist is very thin, which is actually a feature they are known for by locals in their natural habitat, and the tail is longer than the rest of the body, thus providing balance.

Although omnivores, mangabeys will mostly eat plants, fruits and seeds. They have cheek pouches for food collection while they forage.

This species is subject to intense, uncontrolled poaching for its meat; it is larger than other species it shares habitat with and is thus more attractive to poachers because it provides more meat per unit effort. It is also threatened by loss of forest habitat in the south of its range.