White-Naped Mangabey, Cercocebus lunulatus
WHITE-NAPED MANGABEY
Cercocebus lunulatus
Geographic Distribution and Habitat
The white-naped mangabey (Cercocebus lunulatus), also known as the white-collared or white-crowned mangabey, is native to the West African countries of Côte d’Ivoire and Ghana, and possibly a small area in Burkina Faso. White-naped mangabeys were first discovered in Burkina Faso in 2006, and by 2014, they were already believed to be extirpated (made locally extinct) or close to it. Their range is now patchy and significantly smaller than it has been historically, particularly in Ghana. While white-naped mangabeys used to roam throughout much of the country, scientists believe they are now restricted to just two protected areas within Ghana—Cape Three Points Forest Reserve and the Ankasa-Tano Community Forest. One of the most important areas for the species is the Tanoé swamp forest in Côte d’Ivoire, where groups of up to 300 individuals have been reported. White-naped mangabeys make their homes in primary and secondary gallery and swamp forests in the Upper Guinean rain forests of West Africa, a biodiversity hotspot. Primary forests are those that are very old, as they have been relatively undisturbed for a long period of time. Secondary forests are younger, as they have regrown after a significant disturbance, like a timber harvest or fire. Gallery forests are those that are situated along rivers and wetlands, while swamp forests grow in waterlogged areas.
White-naped mangabeys have previously been considered a subspecies of the sooty mangabey (C. atys). In 2016, the International Union for Conservation of Nature declared them to be their own species. Confusingly, sooty mangabeys are also sometimes referred to as “white-collared mangabeys,” which is an alternative name for the white-naped mangabey. Even more confusingly, both sooty mangabeys (C. atys) and white-naped mangabeys (C. lunulatus) were previously considered subspecies of the collared mangabey (C. torquatus). If this is too much to keep track of, just remember that white-naped mangabeys don’t care what they’re called or where they fall in a taxonomic tree. As of the time of this writing, scientists consider white-naped mangabeys to be their own species—related to, but separate from, sooty mangabeys and collared mangabeys.
Because white-naped mangabeys have only recently been elevated to full species status, much of their life history and behavior information was learned from research that considered them a subspecies of sooty mangabeys. In all likelihood, their behavior is similar to their cousins, but scientists won’t know all of their differences until they’ve been comprehensively studied as their own species, which may be years down the line—years we may not have to spare.
Size, Weight, and Lifespan
White-naped mangabeys weigh between 11 and 20 lbs (5–9 kg) for females and 19 and 30 lbs (8.5–14 kg) for males. Female head and body length ranges from 16–24 inches (40–60 cm), and male length ranges from 19–26 inches (47–67 cm). Their tails are 16–32 inches (40–80 cm) long. In the wild, they live to an average age of about 18 years, while in captivity they live an average of 27 years.
Appearance
White-naped mangabeys are a soft brown-gray over most of their body except for the undersides. Their belly, their neck, and the insides of their arms and legs are a creamy white. The white on their neck creeps around towards their nape in the shape of a half-moon. Their hair is quite long, and it flares out at their cheeks, giving them their alternate name of “white-collared mangabeys.” Their face is bald and features two large, closely spaced eyes. White-naped mangabeys are distinguished from sooty mangabeys by a whorl of hair on the top of their head, a darker face, and the white patch on the napes of their necks. White-naped mangabeys have very long arms and legs and a tail, which they use to agilely navigate their environment. Male white-naped mangabeys are bigger than females, with longer canine teeth.
Diet
White-naped mangabeys are frugivores, or fruit-eaters, and consume fruits and nuts primarily. They supplement this diet with stems, roots, grass, seeds, fungus, and invertebrates. They are well evolved to this lifestyle: they have extremely powerful jaws that can easily crack tough casings around fruits and nuts. Males and females actually have slightly different diets: males consume more of the very tough nuts and seeds, while females focus more on softer fruits.
Behavior and Lifestyle
White-naped mangabeys are mostly terrestrial, meaning that they spend most of their time on the ground, although they climb trees to escape predators. They are quadrupedal—they use all four of their limbs to get around. They spend most of their day, about 75% of it, looking for or eating food, and the rest of their time is spent moving, resting, and socializing. When resting, they prefer to sit on something like fallen branches or a dead tree, rather than sitting directly on the ground. Like almost all primates, white-naped mangabeys are highly social, and they are virtually always within just a few feet (about a meter) from their group mates.
Like many other frugivorous primates, white-naped mangabeys are considered to be particularly intelligent. They need to have excellent spatial memory to recall which trees are fruiting and where they are. They can visually determine whether a tree is fruiting, and can remember where fruit has fallen so they can later retrieve it. There is even evidence that they can remember particular trees that tend to bear more fruit than others.
You may have heard of primates using tools like sticks and stones to break open nuts or dig for termites, well mangabeys have been observed using stones to, of all things, clean their baby’s eyelashes!
As of 2019, there have only been two white-naped mangabeys photographed in the wild in Ghana, a country where they had once been relatively widespread.
White-naped mangabeys live in multi-male multi-female groups ranging in size from 15 all the way up to 100 individuals. Males are typically more aggressive than females, who are more often submissive and on the receiving end of antagonistic behaviors. Males and females each have their own dominance hierarchy, with all males over the age of about five years ranking above all females. Females are born into their rank, which is close to their mother’s rank, and it remains relatively stable for their whole life. Males, on the other hand, are born with a rank similar to their mother’s, but it will change drastically throughout their life. When they are about four years old and their large canine teeth grow in, their rank increases dramatically. They are in a contest with other males for the rest of their life, in a fight to become the alpha male.
The highest-ranking male has the most success at mating. Males are aggressive with each other and are sometimes aggressive to females as well. That said, most aggression among white-naped mangabeys doesn’t actually do harm—bites are usually light, and don’t inflict damage. Females are usually peaceful with one another, although exceptions to this have been observed. Sometimes non-resident males attack a female and her offspring. The male or males that mated with her previously—and thus may be the father of her baby—fiercely defend the female and her offspring against such attacks. Thus, it is to the female’s benefit to mate with multiple males, even if only one can father her baby because she will have many protectors for her and her offspring.
White-naped mangabeys make a variety of sounds. Grunts are commonly heard, usually from males while foraging for food. Twitters are heard from females and juveniles during social interactions. Screams are emitted by females and juveniles during antagonistic interactions. What scientists have deemed “whoop gobbles” are long calls by males that are used for contacting other groups. White-naped mangabeys also use alarm calls when they see a predator. It’s believed that they use different calls for different types of predators.
Body language and facial expressions are also likely very important forms of communication for white-naped mangabeys, but unfortunately, scientists do not understand them very well. Eyelid raising is believed to be threatening, and a grin with a protruded tongue is commonly seen, but researchers are not clear on what purpose it serves.
White-naped mangabeys are polygynandrous—meaning that both females and males have multiple partners. The breeding season lasts from May to September, with a peak in July and August. Females have obvious outward signs of fertility in the form of genital swellings. When she is receptive, a female presents herself to a male partner to breed. Her pregnancy lasts about five and a half months, after which she gives birth to a single baby. On average, she will give birth again 13 to 16 months later.
The baby begins his life being carried on his mother’s stomach for a few months, after which he clings to her back. He is given intense attention for about the first seven months of his life. After this point, he is less needy and is given more general attention from his mother. He will continue to nurse until he is about 10 months of age. His mother has help in child rearing—his aunts actually groom him more than his own mother does! His older siblings also groom any juvenile that they’re related to.
Males start displaying sexual behaviors, such as mounting, at as young as one year of age, but they are not physically mature until the age of about five or six. In fact, juvenile males mount females more often than fully mature males do! Females become sexually mature at the age of about three years, and they give birth for the first time about a year later.
As frugivores, white-naped mangabeys likely serve an important role as seed dispersers in their habitat. They are likely predated upon by eagles, leopards, and even chimpanzees. They are known for their high levels of spatial awareness—it is extremely difficult for a predator to sneak up on a group of white-naped mangabeys.
The International Union for Conservation of Nature lists the white-naped mangabey as Endangered (IUCN, 2019), appearing on the IUCN’s Red List of Threatened Species. Their population is in rapid decline, especially in Ghana. It is believed that in the last 27 years, their population has declined by at least half, although it may have been even more than this. The major threats against white-naped mangabeys are habitat loss and hunting pressure.
Hunting is one of the main threats against white-naped mangabeys. They are hunted both for local consumption as well as for the bushmeat trade. They are also sometimes killed as crop pests. Habitat loss is another significant threat. Habitat is lost due to clearing for agriculture and rubber plantations, charcoal production, firewood, and forest fires. In some protected areas—though that term is used rather loosely, in this case—entire forests have been converted to plantations and white-naped mangabeys have been completely extirpated, or made locally extinct, from the area. Exacerbating this are the impacts from climate change. The three countries that make up the white-naped mangabeys’ home range, Côte d’Ivoire, Ghana, and Burkina Faso, contribute very little to global greenhouse gas emissions, yet are subject to significant impacts from the changing climate. The home range of white-naped mangabeys is experiencing significantly warmer annual temperatures, a longer dry season, and more erratic rainfall. Droughts are also expected to become more common. These changes will have innumerable and, in many ways, unpredictable impacts on the ecology of the region. It will add untold stress to a species that has only recently been recognized as a species and has already lost half of its population.
White-naped mangabeys are listed in Appendix II of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival. They are listed in Class B of the African Convention on the Conservation of Nature and Natural Resources, an important legal framework in Africa for natural resource conservation.
They are found in a number of protected areas, including Comoé National Park and the Tanoe-Ehy Community Forest in Côte d’Ivoire and Atewa Forest Reserve in Ghana. They were formerly protected by Bia National Park, Krokosua Hills Forest Reserve, and the Mamre Forest Reserve in western Ghana, although they have since been extirpated in these areas.
- Galat, G., & A. Galat-Luong. 2006. Hope for the survival of the Critically Endangered white-naped mangabey Cercocebus atys lunulatus: A new primate species for Burkina Faso. Oryx, 40(3): 355-357. doi:10.1017/S0030605306000986
- Ginn, L., K. Nekaris. 2014. The First Survey of the Conservation Status of Primates in Southern Burkina Faso, West Africa. Primate Conservation, 28:129-138
- Nolan R. et al. 2019. Camera Traps Confirm the Presence of the White-naped Mangabey Cercocebus lunulatus in Cape Three Points Forest Reserve,Western Ghana. Primate Conservation, 33.
- https://www.iucnredlist.org/species/4206/92247733
- https://www.zoobarcelona.cat/en/animals/whitenaped-mangabey
- https://animaldiversity.org/accounts/Cercocebus_atys/
- https://primate.wisc.edu/primate-info-net/pin-factsheets/pin-factsheet-sooty-mangabey/
- https://www.worldbank.org/en/country/cotedivoire/publication/cote-d-ivoire-economic-update-so-tomorrow-never-dies-key-messages
Written by K. Clare Quinlan, March 2023