The sooty mangabey (Cercocebus atys) is a medium‑sized Old World monkey belonging to the family Cercopithecidae. Endemic to the Upper Guinean forest block of West Africa, its range extends across southern Côte d’Ivoire, Liberia, Guinea, Sierra Leone and western Ghana. It inhabits primary and secondary tropical rainforests, swamp forests and forest‑edge habitats, often favoring dense canopy and lianas where it can move agilely. The species displays a uniformly dark, sooty‑gray pelage with a bare, pinkish face and a distinctive white beard on the chin. Adult males are larger than females, weighing up to 9 kg and measuring about 55 cm in head‑body length, while females are slightly smaller. Sooty mangabeys are diurnal and highly social, forming large multimale‑multifemale troops that can exceed 30 individuals. Their vocal repertoire includes loud “coughs” and “whoops” used for cohesion and predator alerts. The IUCN classifies the species as Vulnerable, with an estimated total population of 150,000–200,000 mature individuals, declining due to habitat loss and hunting. Conservation actions focus on habitat protection, anti‑poaching patrols, and community‑based education programs.

Sooty mangabeys live in cohesive troops that typically consist of several adult males, multiple adult females, sub‑adults and juveniles. Troop size varies from 10 to over 30 individuals, depending on food availability and forest structure. Within the group, females maintain strong matrilineal bonds, grooming each other frequently, while males compete for dominance and access to estrous females. The species is diurnal, spending the early morning foraging in the lower to mid‑canopy and resting in shaded tree crowns during the hottest hours. Home ranges average 10–15 km², with overlapping territories among neighboring troops that are defended through vocal displays and occasional chase. Communication relies on a rich vocal repertoire—sharp “coughs” signal predator presence, while softer “purrs” and “coos” facilitate social bonding. Visual signals such as facial expressions and body postures also play a crucial role in maintaining hierarchy and coordinating group movements.

The sooty mangabey is an omnivorous forager with a strong preference for fruit, seeds, and insects. Fruit constitutes roughly 50 % of its diet during the peak fruiting season, especially figs (Ficus spp.), drupes, and small berries. When fruit is scarce, the monkey supplements intake with leaves, bark, and a variety of arthropods such as termites, beetles, and caterpillars, which can account for up to 30 % of protein intake. In coastal swamp forests, they also consume mollusks and small vertebrates opportunistically. Daily food intake averages 1.5–2 kg of material, obtained through a combination of hand‑picking, probing bark crevices, and using cheek pouches to transport food to safe feeding sites. Their dentition—sharp incisors and robust molars—facilitates both fruit pulp extraction and insect exoskeleton crushing. Seasonal fluctuations in food availability drive ranging behavior, with troops expanding their home range during lean periods to locate alternative food sources.

Females reach sexual maturity at 4–5 years, males at 5–6 years, although dominant breeding males are often older. The breeding season is not strictly seasonal, but conceptions peak during the rainy months when fruit abundance is highest. Gestation lasts 165–170 days, after which a single infant is born, weighing about 300 g. Newborns are carried ventrally for the first 2–3 weeks before transitioning to riding on the mother’s back. Infants are weaned at 12–18 months but remain in the natal troop for several years, learning foraging techniques and social cues. Females typically give birth every 2–3 years, and interbirth intervals are influenced by food availability and female rank. High maternal investment, prolonged lactation, and alloparental care—where older siblings and other troop members assist in infant protection—enhance juvenile survival in the dense forest environment.

The IUCN lists the sooty mangabey as Vulnerable, with an estimated decline of 30 % over the past three generations. Primary threats include rapid deforestation for timber extraction, cocoa and oil‑palm plantations, and expanding human settlements, which fragment the continuous forest habitat essential for large troop cohesion. Hunting for bushmeat remains a significant pressure, especially in Liberia and Côte d’Ivoire, where the species is targeted for its meat and occasionally captured for the illegal pet trade. Fragmented populations suffer reduced genetic diversity, increasing susceptibility to disease; indeed, the species is a natural reservoir for the simian immunodeficiency virus (SIV) that can cross‑species transmit to humans. Conservation measures focus on establishing and enforcing protected areas such as Taï National Park, promoting community‑based forest management, and conducting anti‑poaching patrols. Ongoing research monitors population trends, while education programs aim to reduce bushmeat consumption. Current estimates suggest 150,000–200,000 mature individuals remain, but continued habitat loss could push the species toward Endangered status within the next decade.

• The sooty mangabey is one of the few primate species known to naturally carry SIV, the precursor of HIV‑2.
• It has a distinctive white beard on its chin that contrasts with its dark facial skin.
• Troops can include more than 30 individuals, making them among the largest social groups of African monkeys.
• Unlike many mangabeys, it prefers dense, low‑light forest understory rather than open savanna.
• It uses cheek pouches to store up to 30 % of its daily food intake while foraging.