SOOTY MANGABEY
Cercocebus atys
Geographic Distribution and Habitat
The sooty mangabey (Cercocebus atys), also known as the white-crowned or white-collared mangabey, is a mostly terrestrial Old World monkey. Its distribution once ranged from the Casamance River in Senegal to the Sassandra/Nzo River system. Today, the species’ range is restricted to the west coast of Africa in Sierra Leone, Liberia, and the western Ivory Coast where these foraging monkeys can be found walking along the forest floor gathering fruits and seeds. Sooty mangabeys are considered to be mostly extinct in Senegal, Guinea-Bissau, and parts of Guinea.
West Africa’s tropical high forest is the species’ primary habitat, but sooty mangabeys also live in primary, secondary, flooded, dry, gallery, and mangrove forests; they've also been known to venture onto farmland in Ghana. Although sooty mangabeys spend the majority of their time on the ground, they will climb trees to avoid or escape predators.
The sooty mangabey (Cercocebus atys), also known as the white-crowned or white-collared mangabey, is a mostly terrestrial Old World monkey. Its distribution once ranged from the Casamance River in Senegal to the Sassandra/Nzo River system. Today, the species’ range is restricted to the west coast of Africa in Sierra Leone, Liberia, and the western Ivory Coast where these foraging monkeys can be found walking along the forest floor gathering fruits and seeds. Sooty mangabeys are considered to be mostly extinct in Senegal, Guinea-Bissau, and parts of Guinea.
West Africa’s tropical high forest is the species’ primary habitat, but sooty mangabeys also live in primary, secondary, flooded, dry, gallery, and mangrove forests; they've also been known to venture onto farmland in Ghana. Although sooty mangabeys spend the majority of their time on the ground, they will climb trees to avoid or escape predators.
Sooty mangabey geographic range. Map credit: Chermundy and IUCN
Size, Weight, and Lifespan Sooty mangabeys are medium-sized monkeys and sexually dimorphic, with males measuring 18 to 26 in (47 to 67 cm) in length and weighing about 5 to 26 lb (7 to 12 kg), and females being slightly smaller, measuring 17 to 24 in (45 to 60 cm) and weighing 10 to 15 lb (4.5 to 7 kg). A male is about as heavy as a dachshund dog, and a female sooty mangabey weighs about as much as the average house cat. Male sooty mangabeys have longer canine teeth than females. Both sexes have long tails,16 to 31 in (40 to 60 cm), that help them with balance when running, playing, or foraging. As is typical of Old World monkeys, sooty mangabeys’ tails are not prehensile; that is, their tails are incapable of grasping objects. Sooty mangabeys live to be 18 years old in the wild. Appearance Imagine the soot that covers someone after cleaning a chimney or the ashes left in your fire pit when you go camping; this is the color of the sooty mangabey. Sooty mangabeys are cloaked in dark, ash-gray fur; the fur on their underside is a lighter, smoky-gray color. Their hands, feet, and ears are dark gray or black. The skin on the sooty mangabey’s hairless face is either a salmon color or a mottled gray, and their long muzzle is dark. Light-colored whiskers extend from the monkey’s cheeks, adding contrast to the dark fur framing the face. Bright, white eyelids suggest an expression of surprise. Sooty mangabeys make use of their bright eyelids, raising and lowering them, to communicate with others. 
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What Does It Mean?Gallery forest:
A forest that serves as a corridor along rivers or wetlands and projects into landscapes that are otherwise sparsely treed, such as savannas, grasslands, or deserts. Mangrove forest: A mangrove refers to two different things: a tidal swamp ecosystem found in tropical deltas, estuaries, lagoons or islands, and the characteristic tree species populating this ecosystem. Mangrove trees have developed unique adaptations to the harsh conditions of coastal environments. Phylogeny: Evolutionary history of a related group of organisms. Primary forest: Also termed old-growth forest, virgin forest, or primeval forest—a forest that has attained great age without significant disturbance and thereby exhibits unique ecological features and might be classified as a climax community, an ecological community in which populations of plants or animals remain stable and exist in balance with each other and their environment. Secondary forest: A forest that has regrown after a major disturbance, such as fire or timber harvest, but has not yet reached the mature state of primary forest. Sexually dimorphic: When males and females have different characteristics (size, color, etc.) other than their reproductive organs. Terrestrial: Living on the ground. |
Diet
Sooty Mangabeys are omnivores; that is, they eat both plants and animals. Fruits and seeds comprise the greater part of their diet, with insects comprising a much smaller portion. Grass, fungi, small invertebrates, and dinner delicacies like tadpoles plucked from shallow ponds round out their menu.
Strong, powerful jaws and large incisor teeth enable sooty mangabeys to eat hard objects that many other animals cannot eat, including nuts with hard kernels and palm nuts, both the flesh and kernels. This natural adaptation helps ensure the species’ viability.
Due to the size difference in their incisor teeth, male and female sooty mangabeys have different dietary preferences, or proclivities. With his larger incisor teeth, the male sooty mangabey eats more hard nuts, seeds, and crunchy invertebrates. The female, with her daintier incisor teeth, prefers to eat softer seeds and fruits.
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Fun FactsSooty mangabeys help anthropologists develop hypotheses on human eating and foraging behaviors, because these monkeys are phylogenetically closely related to humans. Natural carriers of the simian immunodeficiency virus (SIV-1), which is similar to human immunodeficiency virus (HIV-2) in humans, sooty mangabeys do not become ill from the virus. Sooty mangabeys, like humans, the nine-banded armadillo (Dasypus novemcinctus), the common chimpanzee (Pan troglodytes), and the rhesus macaque (Macaca mulatta), can contract and spread leprosy. Sooty mangabey are incredibly effective at spotting predators. Mothers have been observed grooming their infants with a stone, but researchers are unsure why. This may be an example of tool use. Sooty mangabeys remember the locations of fallen fruit and can determine whether or not a tree is producing fruit. |
Daily Life and Group Dynamics
Sooty mangabeys are diurnal, meaning that they are active during daylight hours. Most of their day is spent on the ground foraging for food. They cover their territory by moving quadrupedally, that is, on all fours. Their time spent in trees is limited and is restricted to the forest understory, where they climb or leap. Sooty mangabeys spend a large amount of their day resting and interacting socially with members of their group.
Group size can range from 15 to more than 100 individuals, typically with more males than females. These monkeys are always within 3 ft (1 m) of another group member, and they huddle even closer during severe weather.
The social structure of a group is dominated by a male hierarchy, with an alpha male at the top, followed by the other males in the group, followed by an alpha female, followed by the other females in the group.
An alpha male may attempt to copulate with all the females of a group. Males with higher status, or ranking, mate more frequently. During copulation, males can be aggressive and sometimes slap the females.
Males might leave their group for months at a time to interact with other females in nearby groups. These wandering males have been known to commit infanticide; they deliberately kill the infants of an established group with the goal of taking over the group and siring their own offspring. Females remain with their natal (birth) group. Despite male aggression toward females and infants, sooty mangabeys display some of the lowest rates of aggression and combative behavior among primates.
Sooty mangabeys have been observed in mixed groups with other primate species. Researchers believe that these mixed groups offer added protection against arboreal and terrestrial predators. Diana monkeys (Cercopithecus diana) and red colobus monkeys (Piliocolobus badius), who are mostly arboreal (tree-dwelling), will risk feeding closer to the ground, knowing that the sooty mangabey’s loud alarm calls will alert them to potential danger.
Communication
Sooty mangabeys are vocal monkeys. Grunts, twitters, screams, growls, and alarm calls are used to communicate. Grunts are more often elicited by males; these low-frequency vocalizations typically accompany foraging activities. Twitters, which can be either soft- or sharp-sounding and have up to 23 syllables, are used by adult females or by juveniles who are interacting socially. Screams are more common to adult females, usually sounded in response to male aggression. Growls accompany aggressive behavior.
Alarm calls warn group members of potential predator threats. They use unique alarm calls to identify each predator type. For example, one call identifies a leopard, while another identifies a Gaboon viper, and another still identifies a threat from above, like an eagle. Different calls enable the group group members to determine how best to seek out safety either above or below the predator’s location.A female sooty mangabey is able to recognize an alarm call elicited from a member of her own group, so she can potentially protect her young from an attack by a wandering male from an outside group.
Sooty mangabeys use facial expressions to communicate. When raising their bright white eyelids, they are threatening another monkey. Other expressions—such as when these monkeys “grin” and stick out their tongues—are less understood by researchers.
Sooty mangabeys are vocal monkeys. Grunts, twitters, screams, growls, and alarm calls are used to communicate. Grunts are more often elicited by males; these low-frequency vocalizations typically accompany foraging activities. Twitters, which can be either soft- or sharp-sounding and have up to 23 syllables, are used by adult females or by juveniles who are interacting socially. Screams are more common to adult females, usually sounded in response to male aggression. Growls accompany aggressive behavior.
Alarm calls warn group members of potential predator threats. They use unique alarm calls to identify each predator type. For example, one call identifies a leopard, while another identifies a Gaboon viper, and another still identifies a threat from above, like an eagle. Different calls enable the group group members to determine how best to seek out safety either above or below the predator’s location.A female sooty mangabey is able to recognize an alarm call elicited from a member of her own group, so she can potentially protect her young from an attack by a wandering male from an outside group.
Sooty mangabeys use facial expressions to communicate. When raising their bright white eyelids, they are threatening another monkey. Other expressions—such as when these monkeys “grin” and stick out their tongues—are less understood by researchers.
Reproduction and Family
Sooty mangabeys have a promiscuous breeding system: both males and females have multiple partners. Mating season begins in May and ends in September in the wild, but births can occur year-round.
Males become sexually active at about 1 year old, but they are not considered sexually mature (capable of siring offspring) until 4 years old. They copulate more often as adolescents, prior to achieving sexual maturity.
Females are considered sexually mature (capable of conceiving) at about 2.5 to 3 years old. They present themselves to the males to initiate copulation. Unlike other promiscuous breeding systems, female sooty mangabeys are not aggressive toward one another. A single infant is born after a gestation period of 167 days. The time between births is typically 14 to 16 months.
Once an infant is born, the mother carries him or her on her ventral side (stomach); after a few months, she carries the baby on her back. From 2 to 7 months, the mother is the child's primary caregiver. However, if a threat presents itself, males might carry the youngster to offer greater protection. Once the child is older, aunts and siblings help groom the youngster.
Should a child die within the first 6 months of its life, the mother immediately goes back into estrus. This condition gets the attention not only of dominant males within her group, but also from wandering males. Older and higher-ranking males of the female’s group do their best to protect her and the group’s surviving infants from wandering males, but they are not always successful.
Ecological Role
Because of their tendency to take one bite of a fruit before tossing it to the ground, sooty mangabeys might mistakenly be thought of as wasteful. But they are actually helping to maintain the health of their ecosystem. Their discarded fruit, along with the seeds distributed through their feces, are essential in helping to regenerate plant life throughout the sooty mangabey’s habitat.
Because of their tendency to take one bite of a fruit before tossing it to the ground, sooty mangabeys might mistakenly be thought of as wasteful. But they are actually helping to maintain the health of their ecosystem. Their discarded fruit, along with the seeds distributed through their feces, are essential in helping to regenerate plant life throughout the sooty mangabey’s habitat.
Conservation Status and Threats
The sooty mangabey is classified as Near Threatened by the International Union on Conservation of Nature (IUCN, 2016). Its subspecies, the white-naped mangabey (Cercocebus lunulatus), is already classified as Endangered.
Human activity poses a significant threat to the sooty mangabey, through habitat loss and hunting. The original size of the sooty mangabey’s habitat has been reduced by over 90%, transformed into agricultural tracts of land. Forests are becoming smaller and fragmented, causing sooty mangabeys to forage for food in these agricultural areas where farmers regard the monkeys as crop pests. Because sooty mangabeys are terrestrial, they are easily caught in traps set by the farmers. The monkeys are also hunted and killed for their meat.
Sooty mangabeys and other primates are studied in Taï National Park, which is located in the Ivory Coast and borders Liberia. Research shows that the rate of hunting is double the species’ reproductive rate to naturally sustain the species, which has already suffered a 25% decline in population.
Conservation Efforts
Taï National Park, one of the last primary forests in West Africa, is home to a wild study site of the sooty mangabey.
The sooty mangabey is classified as Near Threatened by the International Union on Conservation of Nature (IUCN, 2016). Its subspecies, the white-naped mangabey (Cercocebus lunulatus), is already classified as Endangered.
Human activity poses a significant threat to the sooty mangabey, through habitat loss and hunting. The original size of the sooty mangabey’s habitat has been reduced by over 90%, transformed into agricultural tracts of land. Forests are becoming smaller and fragmented, causing sooty mangabeys to forage for food in these agricultural areas where farmers regard the monkeys as crop pests. Because sooty mangabeys are terrestrial, they are easily caught in traps set by the farmers. The monkeys are also hunted and killed for their meat.
Sooty mangabeys and other primates are studied in Taï National Park, which is located in the Ivory Coast and borders Liberia. Research shows that the rate of hunting is double the species’ reproductive rate to naturally sustain the species, which has already suffered a 25% decline in population.
Conservation Efforts
Taï National Park, one of the last primary forests in West Africa, is home to a wild study site of the sooty mangabey.
Video and photos courtesy of ARKive.org
References:
- http://pin.primate.wisc.edu/factsheets/entry/sooty_mangabey
- http://animaldiversity.org/accounts/Cercocebus_atys/
- http://www.arkive.org/sooty-mangabey/cercocebus-atys/video-00.html
- https://en.wikipedia.org/wiki/Sooty_mangabey
- http://www.learnersdictionary.com
- http://www.encyclopedia.com/science/news-wires-white-papers-and-books/seed-dispersal
- http://www.fao.org/home/en/
- http://www.biology-online.org/dictionary
- https://www.merriam-webster.com/dictionary
Written by Laura Fern, December 2017
