Rain forests of western Cameroon, southeastern Nigeria and the West African Island of Bioko, a part of Equatorial Guinea. They are highly endangered due to habitat destruction and hunting. They have a whiteish beard around their face with a scarlet patch just below their lower lip.
Drills spend a lot of time on the ground looking for food, however, they are excellent climbers.
Their nests are in the trees. Males can weigh up to 50 kg and are much larger than the females. Drills breed year round. They live in troops of over 20 drills and have been known to congregate with other troops to form a gathering of over 150 drills. Scientists are not sure how long they live in the wild.