Mandrillus

Mandrillus is a genus of Old World monkeys in the family Cercopithecidae. The genus is best known for two species: the mandrill (Mandrillus sphinx) and the drill (Mandrillus leucophaeus). Member species are large, robust primates with distinctive facial coloration and large cheek pouches used for storing food. Male mandrills possess strikingly colorful faces and chests, with bright blues and reds on the upper lip and chest, while females have more subdued coloration. Drills are generally less colorful, with grayish to yellowish faces and brownish bellies.

These monkeys are native to sub-Saharan Africa. The mandrill is found in forests and woodland savannas across West and Central Africa, ranging from Sierra Leone to the Democratic Republic of the Congo. Drills inhabit the dense tropical rainforests of western Central Africa, particularly in the region of the Republic of the Congo, Gabon, and the Cabinda enclave of Angola. Both species are arboreal but also spend significant time on the forest floor.

Mandrillus species are nocturnal or crepuscular in some populations, feeding primarily on fruits, seeds, leaves, and occasionally insects. They live in small groups of 3–10 individuals, with larger troops observed during breeding or foraging. Social structures are complex, involving hierarchies and frequent grooming interactions. Reproduction is seasonal, with litters usually consisting of one infant after a gestation of about 5 months.

Conservation assessments classify the mandrill as Least Concern, although populations are declining in some regions due to habitat loss and hunting for meat. Drills are listed as Endangered, with an estimated decline of 30–50% over the last 24 years, largely from habitat destruction and overhunting. Conservation measures include protected area designation, anti-poaching patrols, and community education programs aimed at reducing bushmeat exploitation. Scientific interest in Mandrillus extends to studies on primate communication, social behavior, and the impacts of habitat fragmentation on genetic diversity.