Class: Mammalia (Mammal)
Body length: 15 to 35 inches (38 to 89 centimeters)
Tail length: 17 to 39 inches (43 to 100 centimeters)
Weight: 7 to 44 pounds (3 to 20 kilograms)
Life span: up to 30 years
Gestation: 5½ to 6 months
Number of young at birth: usually one, twins are rare
Weight at birth: 18 to 21 ounces (500 to 600 grams)
Age of maturity: 4 to 5 years
Conservation status: all mangabey species are endangered.
• Adult male mangabeys make a sound that biologists call a "whoop-gobble." The "whoop" gets the attention of other mangabeys in the area; the "gobble" tells everyone who and where he is. This unique call may be heard for a distance of up to 1,000 yards (1 kilometer).
• A new species of mangabey was recently identified in Tanzania. It's found in forests up to 8,000 feet (2,450 meters) in elevation and is named the highland mangabey Lophocebus kipunji. Researchers say the "new" mangabey makes an unusual "honk bark" sound, very different from the sounds other mangabey species make. The species is already considered highly endangered due to illegal logging that has destroyed parts of its habitat.
• The mangabey was named for what Europeans thought was their homeland. The first shipment of these primates was labeled as coming from Mangabe, a port in Madagascar. But there are no mangabeys native to Madagascar!
• The genus name Cerocebus means "tail monkey" in Greek; the genus name Lophocebus means "crest monkey."
Mangabeys are some of the most rare and endangered monkeys on Earth. These large, forest-living monkeys are found only in Africa. They look somewhat like guenons but are bigger. Local people call some of them "the ones with the thin waist" or "four-eyed monkeys" because some mangabey species have bright white eyelids. Taxonomists have put mangabeys into two separate genera: white-eyelid mangabeys Cerocebus sp. and crested mangabeys Lophocebus sp., based on physical differences. White-eyelid mangabeys are most closely related to mandrills and drills, and the males are much larger than the females; crested mangabeys are more closely related to baboons and geladas and both males and females are about the same size. All mangabeys have tails that are longer than their bodies, providing balance for them as they scamper through the rain forest canopy.
Depending on the species or subspecies, mangabeys can be golden brown, gray, dark brown, or a soft black, usually with a lighter color on their underbellies. Youngsters are usually darker than the adults. White-collared mangabeys Cerocebus torquatus have reddish hair on their heads, a "beard" on each cheek, and white hair that wraps around their neck like a collar (hence the name!). Black mangabeys Lophocebus atterimus have long, grayish brown whiskers that almost cover their ears and a high crest on their head—a pointy hairdo!
A swingin' home
Like most monkeys, mangabeys are very much at home in trees, spending most of their time there. However, white-eyelid mangabeys are also comfortable on the ground, traveling on their hands and feet between patches of forest or to forage in the leaf litter for tasty food items. In some areas of the forest, the ground is swampy, but it’s not a problem for the mangabeys. Webbing between their fingers and toes helps these amazing monkeys to swim! All mangabeys are excellent jumpers, and gray-cheeked mangabeys Lophocebus albigena and white-collared mangabeys have tails that are strong enough to help them hook on to branches as they leap about the forest canopy.
Mangabeys live in groups, called troops, of about 10 to 40 individuals, depending on the species and the availability of food and habitat. There is usually one adult male that acts as leader and the troop's defender, but sometimes the larger troops have two or three adult males that split off with their own family units to forage for food. When a male becomes sexually mature he leaves his troop to find another one to join. If he can't find one, he will live alone until he does; single males do not form all-male groups. When there is plenty of food available, mangabey troops will often gather together for a while and even exchange troop members.
Mangabeys have some interesting ways of communicating with each other. It's often hard to see one another in the dense forest canopy, so sound is very important. In fact, mangabeys can be very noisy! A special throat sac gives them booming voices. The sac is larger in the adult male—he can make shrieking alarm calls to alert others to danger, and he barks, twitters, and grunts to let other mangabey troops in the area know where his troop is so they don't accidentally intrude. The adult females often join in with a loud chorus!
White is an important color when you need to get your point across. White-collared mangabeys use movements of their white-tipped tails to express themselves. White hair on the underside of the chin of the monkeys helps make other facial gestures more noticeable. For white-eyelid mangabeys, batting their eyelids and raising their eyebrows can have a whole range of meanings. They communicate using facial expressions, and flashing their white eyelids against their darker fur helps get the message across. Flashing eyelids can mean, "This is a warning—watch your step!"
Bringing up baby
Much like baboons, a female mangabey's buttocks swell when she is ready to breed. This is her visual signal to the males. The single infant is born with soft fur and its eyes are open. Its instinct to grasp onto its mother is so strong that is often grabs at the mother's hair with its hands as it's being born! Newborns will cling to the mother's belly; older infants often ride on her back.
Mangabeys are mainly fruit eaters, although they can also eat leaves, nuts, seeds, insects, and spiders. Powerful teeth and jaws help them crack hard nut shells or bite into thick-skinned fruits. Mangabeys also tear bark off of trees using their teeth and hands to find bugs and spiders that are hiding underneath. Large cheek pouches act like a shopping cart: mangabeys fill their pouches with food until full! The biggest meal of the day for mangabeys is breakfast, and they start foraging for food in the early morning, often before the sun comes up. At the San Diego Zoo the mangabeys are offered leaf eater biscuits, assorted fruits (such as apples, grapes, melons), vegetables (green beans, corn, eggplant), and greens (cabbage, lettuce, kale). Enrichment treats can include raisins, popcorn, and peanuts.
Like so many other rain forest inhabitants, all mangabey species are endangered. Along with other large primates such as chimpanzees and gorillas, they are among the first of the larger mammals to disappear from forests close to human settlements. People continue to destroy mangabey habitat by logging the trees in their forest homes and hunting the monkeys illegally for bushmeat. And because mangabeys are such fruit lovers, they tend to raid fruit plantations and are often killed as pests.
The Association of Zoos and Aquariums (AZA) has developed a Species Survival Plan (SSP) for mangabeys. The SSP is set up to help mangabeys in the wild and works with various zoos to help them care for these primates. The San Diego Zoo is one of only a handful of zoos that exhibits both golden-bellied mangabeys and black mangabeys and is involved in the SSP effort to protect these forest monkeys from extinction.