The mandrill is a large Old World monkey native to west central Africa. It is one of the most colorful mammals in the world, with red and blue skin on its face and posterior. The species is sexually dimorphic, as males have a larger body, longer canine teeth and brighter coloring. It is the largest monkey in the world. Its closest living relative is the drill, with which it shares the genus Mandrillus. Both species were traditionally thought to be baboons, but further evidence has shown that they are more closely related to white-eyelid mangabeys.
Mandrill
Skull of male mandrill, showing the long canines and ridged bone swellings
Male and female mandrills, showing size and color dimorphism
Female mandrill sitting in tree
Old World monkeys are primates in the family Cercopithecidae. Twenty-four genera and 138 species are recognized, making it the largest primate family. Old World monkey genera include baboons, red colobus and macaques. Common names for other Old World monkeys include the talapoin, guenon, colobus, douc, vervet, gelada, mangabey, langur, mandrill, surili (Presbytis), patas, and proboscis monkey.
Old World monkey
A male rhesus macaque (Macaca mulatta)
Young collared mangabey (Cercocebus torquatus).
Black-footed gray langur, (Semnopithecus hypoleucos)