Mandrillus sphinx
mandrill

Mandrills are found in southwestern Cameroon, western Gabon, Equatorial Guinea, and southwestern Congo.

Mandrills are found in tropical rain forest habitats, montane and thick secondary forests, and thick bush. Although they are adapted to live in the ground, mandrills seek shelter in the trees during the night.

Mandrills reach a height of about 80 cm. The species is characterized by a large head, a compact body with long, powerful limbs, and a stubby tail, which is held upright. The wide rotating range of the clavicles enables climbing trees, the quadrupedal walk, and the functioning of the arms. Opposable thumbs allow these monkeys to grasp tree branches. Both sexes have paired mammary glands in the chest region.

The pelage is an olive green with paler underparts. It has a brilliantly colored blue to purple naked rump. A mandrill's face has a red stripe down the middle of the muzzle and aroung the nostrils, while the sides of the muzzle are ridged lengthwise and colored blue. This helps to distinguish this species from drills which have jet black faces. Mandrills have red fur patches above the eyes and a yellow beard. These colorings are duller in females and juveniles than in adult males.

These animals are reported to have average weights of 11.5 for females, and 25 kg for males. Males are significantly larger than females and may weigh up to 54 kg.

The head and body measurements range between 610 and 764 mm.

The maximum lifespan reported for this genus is 46 years.

Mandrill groups can range in size from a few head up to 50 individuals. Although the dominant male often strays from the group, he will return immediately upon any sign of danger. Mandrills live on the ground by day and sleep in trees at night.

Their bright coloring is a key feature in social behavior. When excited, the blue color of the pad on their buttocks intensifies, their chest turns blue, and red dots may appear on the wrists and ankles. The flashing of the bright rump, which originated as a a signal of receptiveness in estruous females, has also been interpreted as an act of submissiveness in both sexes. This behavior, typical between subordinates and dominants, is considered "proper behavior."

To exhibit playfulness, a male mandrill shakes his head and shoulders; this is an invitation to be groomed. The exposure of teeth with the lips slightly lifted, accompanied by occasional chatter, is a sign of friendliness and general well-being.

When angered, mandrills slap the ground violently. They may stare intently at an observer while scratching their forearm or thigh.

A yawning gesture is given when mandrills are unable to carry out a desired activity, such as mating or fighting. This yawning also occurs as part of a threat where the mandrill spreads its arms, displays its lowered head, and flashes its powerful teeth.

Grooming is a common activity and may be accompanied by smacking noises similar to those heard during copulation. Mandrills communicate by grunting while in the forset; this maintains contact where visibility is low.

(Grzimak's, 1972)

As described above in the section for behavior, communication is varied and complex in this species. It involves a variety of components, including visual and accoustic signals, scents, and tactile information.

Mandrills have a highly varied diet including fruit, seeds, fungi, roots, insects, snails, worms, frogs, lizards, and sometimes snakes and even small vertebrates. Generally, mandrill males scrounge for food on the ground while females and their young sit in midlevel trees.

Predators of this species have not been reported, but are likely to include large carnivores, such as leopards.

These monkeys are likely to play some role in seed dispersal. To the extent that they serve as predators or as prey, they may have some effect on local food webs.

In zoos, mandrills can be nuisances becuse they are very skillfull in taking articles from visitors, such as pipes and glasses. At the Zurich Zoo in Germany, glass had to be put up in front of the mandrill display for insurance reasons. In their natural habitat, mandrills may take oil palm fruits from local plantations. When food is scarce, they may also raid crops from nearby farms.

Mandrills are commonly found in zoos. Becuse of their long life spans, they are valuable, longtime residents. The are also hunted for their meat in some areas.

There has been a drastic decline in the mandrill population during recent years due to habitat destruction. They are especially vulnerable to hunters because of their loud calls. Mandrills are hunted as a local food source in several areas. Currently, mandrills occupy forests at a very low density and are poorly protectd if at all. As a result, they may be threatened with complete extinction in the wild. (Gale, 146)