The primate known for its colorful face and recognized as the largest monkey is the mandrill.
Mandrills (Mandrillus sphinx) are large Old World monkeys native to west-central Africa. Adult males have striking red-and-blue facial skin, a red nose, colorful markings on the rump, and long canine teeth. The blue tones are produced by the structure of collagen fibers beneath the skin, while the red reflects blood vessels near the surface.
Mandrills mainly inhabit tropical rainforests but may also cross savanna areas. They eat fruit, seeds, leaves, fungi, insects, and occasionally small vertebrates. Females and young live in large groups called hordes, sometimes numbering in the hundreds; adult males are often more solitary.
A common mix-up is calling a mandrill a baboon. Early naturalists did so because of its size and body shape, but modern classification places mandrills in the genus Mandrillus, alongside the closely related drill. The species is classified as Vulnerable, with habitat loss and hunting among its main threats.