Africa’s largest monkey, the mandrill, Mandrillus sphinx, is being forced out of its home within a national park due to hunting pressure, new research has revealed.

Researchers from the University of Bristol Veterinary School, in collaboration with Bristol Zoological Society and partners in Equatorial Guinea, have uncovered alarming evidence that hunting pressure is dramatically reducing the safe habitat available to mandrills inside Monte Alén National Park, one of Central Africa’s most important rainforest strongholds.

Mandrills, the world’s largest and most colourful monkey species, are listed as Vulnerable by the IUCN and face growing threats from habitat loss and hunting. Despite their crucial role as seed dispersers and indicators of forest health, the species remain poorly studied across much of their range. This new study reveals that even protected areas are failing to offer full refuge.

Using 35 camera traps deployed by Bristol Zoological Society’s Equatorial Guinea Conservation Programme, researchers monitored mandrill presence across the park and the impact of environmental and human influences on their movements.

Across 10,800 camera-trap days, researchers recorded 79 mandrill detections across Monte Alén National Park, and the results were stark. The research revealed that mandrills were far less likely to be present near hunting camps, even within the protected national park. This suggests that hunting pressure is actively reducing the amount of safe habitat available to the species, forcing mandrills to retreat into less disturbed areas.

The study, published in American Journal of Primatology, also found that mandrills were more likely to occupy areas close to rivers, highlighting the importance of riparian habitats for drinking, feeding, and escaping the heat.

Tim Bray, co-author and Conservation Programme Manager at Bristol Zoological Society, said: “This research shows very clearly that hunting pressure is affecting mandrill habitat, even inside a protected area like the national park. If we want mandrills to survive in Monte Alén, we need to protect the places that matter the most for the species and work with communities to reduce pressure on wildlife. Access to water is essential, but hunting pressure can quickly make an area uninhabitable for the species.”

Mandrills focused their activity on a smaller number of high-quality sites during the wet seasons, probably following seasonal food sources. During the dry seasons, they spread more evenly across the landscape. This suggests that mandrills have the ability to adapt to changing conditions, but only in areas with limited human impact.

The results emphasise the pressing need for targeted conservation actions to safeguard essential habitats, particularly areas near rivers, as well as addressing the socio-economic drivers of hunting.

Tania Guzman Santillan, the study’s lead author, who undertook the study as part of her Master’s in Global Wildlife Health and Conservation at Bristol Veterinary School in conjunction with conservationists at Bristol Zoological Society, added: “The persistence of mandrills in Monte Alén will depend on conserving critical habitats, reducing hunting pressure, and helping communities find alternative livelihoods. Without this combined approach, even the largest monkey in Africa could become extinct in a region that was supposed to protect them.”

The University of Bristol’s MSc in Global Wildlife Health and Conservation is a unique programme, taught in collaboration with Bristol Zoological Society, and includes practical experience, field trips, and mentoring from global experts. This study highlights the importance of applied wildlife research and monitoring, as well as the value of training conservation scientists through programmes like this, where hands-on research directly supports the protection of threatened species.