- The Congo rainforest is home to one of Africa’s least-known and most threatened monkeys: the golden-bellied mangabey.
- Golden-bellied mangabeys form extraordinarily large troops of dozens of individuals, and field observations reveal a complex social structure reminiscent of that of humans.
- The species faces significant threats from habitat loss, hunting and illegal trade, with experts pushing for stronger legal protections, including an upgrade from CITES Appendix II to Appendix I listing.
- Conservation efforts are slowly gaining momentum, with priorities including law reform in the Democratic Republic of Congo, upgrading the CITES listing, and conducting comprehensive surveys to better understand the species’ distribution and ecology.
Deep in the Congo rainforest, Edward McLester witnessed a spectacle few scientists have seen: a troop of golden-bellied mangabeys (Cercocebus chrysogaster) causing a ruckus, their vibrant underbellies flashing through the understory.
“Walking through the forest dozens of kilometers from the nearest person and surrounded by 70-odd large monkeys on the ground all screaming and whooping and heading in the same direction was an incomparable experience,” McLester, a conservation biologist at the University of Southampton in the U.K., told Mongabay.
Golden-bellied mangabeys are one of Africa’s least-known and most threatened monkeys. As their name suggests, these monkeys sport a striking golden-yellow to orange-gold belly, a feature unique among mangabeys. Adults typically weigh between 8 and 15 kilograms (18 and 33 pounds), with males being larger than females.
In 2020, and McLester and his team set out to conduct one of the first detailed studies of these primates in the wild at the LuiKotale study site in the buffer zone of Salonga National Park, in the Democratic Republic of Congo. Although outside the official protected area, the four villages that inhabit the area have committed to not hunt south of the Lokoro River to protect the bonobos (Pan paniscus) and other animals there.
Golden-bellied mangabeys form extraordinarily large troops of dozens of individuals. McLester’s observations reveal a complex social structure reminiscent of humans.
“Once one is familiar with individuals, you can see many of the same relationships and quirks we do in humans,” he said. “The mangabeys’ social lives are filled with drama.”
He said that while individuals form friendships, they also irritate each other by snatching food, accidentally stepping on tails, and insisting on trying to groom newborn infants (which annoys the mom). They make up by grooming and playing.
Despite these individual conflicts, the community bands together when faced with external challenges. McLester observed the mangabeys working together to hide from predators and gang up on dangerous snakes like Gaboon vipers (Bitis gabonica).
Their personalities also shone through, McLester said: “While the groups were habituated [accustomed to human presence], some of the older females simply didn’t like me no matter how long I spent with the group and would chirp with irritation when I came close.”
One of the most threatened monkeys
The golden-bellied mangabey is classified as endangered on the IUCN Red List. McLester estimated there are between 10,000 and 30,000 individuals left in the wild, although he called that estimate “very rough.”
In September 2020, Zimbabwean officials made one of the largest known confiscations of illegally traded primates in Africa. They seized 25 juvenile monkeys being smuggled from the DRC to South Africa, including a dozen golden-bellied mangabeys.
The confiscated mangabeys found a new home at the JACK Primate Rehabilitation Centre in the DRC. The center is currently caring for 14 golden-bellied mangabeys, the largest population in captivity in the world.
“Creating a new protected area for them and reducing the illegal wildlife trafficking on the babies and, of course, bushmeat trade and consumption is a major issue!” Franck Chantereau, who runs JACK, told Mongabay in a text message.
The species faces significant threats from habitat loss, hunting for bushmeat, and the exotic pet trade. To combat these threats, conservationists are pushing for stronger protections both internationally and within the DRC.
Currently, the golden-bellied mangabey is listed under the Appendix II of CITES, the global convention on the wildlife trade, which means regulated international trade with proper permits is allowed. However, experts say this is insufficient protection.
“For the golden-bellied mangabey, Appendix II listing is woefully deficient,” John Hart, scientific director of the DRC-based Lukuru Wildlife Research Foundation, told Mongabay. “The endangered status of this species requires Appendix I” — under which trade is prohibited or highly regulated — “and a major effort to halt all hunting of the species in its range.”
Héritier Mpo, who runs APPACOL-PRN, a nonprofit fighting wildlife crime in the DRC, agreed. “They are endemic in the DRC and are systematically targeted by illicit trafficking,” he said, emphasizing the need for protection at both national and international levels.
However, Hart said that while the illegal international trade is a concern, the bigger threat is local. “The big threat is uncontrolled hunting for bushmeat trade in Congo,” he said. To address this, Hart suggested that provincial administrations issue edicts making commerce in golden-bellied mangabeys illegal, followed by public awareness campaigns and enforcement actions.
Conservation efforts are gaining momentum, albeit slowly. McLester outlined the main priorities as “reforming the law in Congo, upgrading the CITES listing, and more surveys to get baseline ecological and distribution data.” Work is underway on all these fronts, including a proposal to upgrade the species to CITES Appendix I and plans for comprehensive surveys.
“In my opinion, a top priority is a coordinated national survey with boots on the ground,” Jo Myers Thompson, president of the Lukuru Wildlife Research Foundation, told Mongabay. Researchers are also planning genetic surveys to understand the distinctiveness of eastern and western subpopulations, which could inform tailored conservation measures.
Meanwhile, it’s safe to assume that these golden primates will continue to be hunted, captured, and pushed from their homes until adequate protections are established.
“This is one of Africa’s least-known primates and, potentially, one of Africa’s most unique primates,” McLester said. “It would be a real shame to lose this fascinating, charismatic species before we even get a chance to understand it.”
Banner image of a subadult golden-bellied mangabey in the wild. Photo courtesy of Edward McLester / Max Planck Institute of Animal Behavior.
Liz Kimbrough is a staff writer for Mongabay and holds a Ph.D. in ecology and evolutionary biology from Tulane University, where she studied the microbiomes of trees. View more of her reporting here.
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