Mandrill, large baboon that lives in the dense rainforests of central W Africa. Mandrills roam in small troops and forage omnivorously for their diet on the forest floor. the brightly-coloured male has a red-tipped, pale blue nose, yellow-bearded cheeks and a reddish rump. Height: 75cm at the shoulder; weight: to 54kg. Family Cercopithecidae; species Mandrillus sphinx.