status: Vulnerable, IUCN Endangered, ESA
range: Cameroon, Congo Republic, Equatorial Guinea, Gabon
Description and biology
Related to the baboon, the mandrill is the largest member of the monkey family. An average male has a head and body length of 31 inches (79 centimeters), a shoulder height of 20 inches (51 centimeters), and a tail length of 3 inches (8 centimeters). It weighs 119 pounds (54 kilograms). Females are considerably smaller.
Male mandrills are considered the most colorful of all mammals. While the animal's body fur is mainly dark brown, its bare areas (face and buttocks) are dazzlingly colored. Bright blue ridges line its face on either side of its nose. Its doglike muzzle is bright red. Black fur surrounds its close-set, yellow-brown eyes. Its beard and the edges of its mane are pale yellow. The pads on its buttocks are bright red, blue, and purple. The coloring on females and infants is not as brilliant.
Mandrills are active during the day, foraging for fruits, buds, leaves, roots, insects, fungus, and seeds. When food is scarce, the animals sometimes raid crops from nearby farms and plantations. At night, they sleep in trees.
Social animals, mandrills form groups of 20 to 40 members headed by a single male. The home range of a single group may be between 12 and 19 square miles (31 and 48 square kilometers). Little is known about the mandrill's reproductive habits. Most female mandrills give birth between December and April after a gestation (pregnancy) period of about 170 days.
Habitat and current distribution
Mandrills are found in the tropical forests and thick bush areas south of the Sanaga River in southwestern Cameroon, Rí Muni (the portion of Equatorial Guinea on the African mainland), western Gabon, and southwestern Congo Republic.
Since mandrills avoid contact with humans, they are difficult to observe in the wild. Biologists (people who study living organisms) are, therefore, unsure of the total number currently in existence.
History and conservation measures
The mandrill population has drastically declined in the late twentieth century due to habitat destruction and hunting. It is relatively easy to hunt mandrills because they emit loud calls. Hunters sometimes use dogs to chase the animals up trees before shooting them down.
Local people hunt the mandrill for food in all countries in its range. Much of the animal's forest habitat has been logged for its timber or cleared to create farmland. Although the animal is found in several reserves, including the Campo Reserve in Cameroon and the large Lopé Okanda Reserve in Gabon, it receives little protection. Hunting, logging, and the building of settlements still take place within many of these areas. In Rí Muni, the mandrill receives no protection and is considered extremely rare.
mandrill, large monkey, Mandrillus sphinx, of central W Africa, related to the baboons. Mandrills are found in forests, while baboons live in open country. The fur of the mandrill is mostly dark brown, but the bare areas—face and buttocks—are patterned in bright colors that are especially spectacular in the adult male, the most colorful of all mammals. The long, heavy doglike muzzle has bright red skin covering the chin, mouth, and nose and extending upward in a narrow strip to the striking, close-set, yellow-brown eyes. The cheeks are bright blue and are folded into an elaborate pattern of ridges. The fur around the eyes is black, and the beard and the edges of the mane are pale yellow. The buttock pads are bright blue, red, and purple. The tail is a short stump. Male mandrills, about 3 ft (90 cm) long, are considerably larger than females and have enormous canine teeth that they display in yawnlike threatening gestures. Mandrills travel on the ground in small family groups, feeding chiefly on insects and vegetation. Powerful animals, and formidable when provoked, they are retiring in habits and avoid contact with humans. They are extremely difficult to observe in the wild. The closely related drill, M. leucophaeus, is also a forest dweller. It is brown with a black face partially outlined in red; the buttock pads are pink. The mandrill and the drill are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Primates, family Cercopithecidae.
man·drill / ˈmandrəl/ • n. a large West African baboon (Mandrillus sphinx) with a brightly colored red and blue face, the male having a blue rump.
drill (in zoology)
drill, monkey: see mandrill.