Drills are good climbers and will readily climb to get fruit, which may be high in the trees. They will usually sleep at night on low branches of trees. They walk on all fours, using the flat surfaces of the foot and hands, not the knuckles as apes do. Drills live in family troops of about 20 or more animals. There is one dominant male per troop, who dominates until a challenge from another mature male is successful.
Grooming is an important part of socializing, as well as keeping individuals parasite free.
It also reinforces hierarchy of the group. Range Drills occupy a very restricted natural range in the rain forests of western Cameroon, eastern Nigeria and the West African Island of Bioko, a part of Equatorial Guinea. Habitat Primarily coastal forests. Diet Diet includes plant matter, insects and small invertebrates. Life Span 30 Years.