A sweeping new study published in the journal Science says that chimpanzee’s complex cultures – including the use of tools and other behaviors – are being lost as human disturbance expands into previously wild areas.

The ten-year study, led by the Max Planck Institute for Evolutionary Biology and the German Centre for Integrative Biodiversity Research, spanned 46 locations 15 countries providing the most complete description of chimpanzee culture to date. WCS, Lincoln Park Zoo, and more than 20 other organizations are co-authors.

Results show the number of behavioral repertoires documented across chimpanzee communities decline with increasing human disturbance suggesting unique cultures of social groups are disappearing just as we expand our knowledge of the breadth of chimpanzee tool-use across equatorial Africa.

Apart from humans, wild chimpanzees show the most diverse and complex tool-using repertoires of all large primates. Early studies by Jane Goodall at Gombe in East Africa and Christophe Boesch in the Tai Forest of West Africa showed that tool technologies differed between populations in ways that were unrelated to ecological factors.

More recently, field studies at sites in Central Africa have built on this knowledge and have discovered some of the most diverse and complex tool behavior ever documented. WCS and Lincoln Park Zoo researchers have conducted long-term research on a remote chimpanzee population in the Goualougo Triangle – a near pristine wilderness in Nouabale-Ndoki National Park Republic of Congo – documenting uses of multiple tool sets of different types of tools to harvest insects.

Said David Morgan of the Goualougo Triangle Ape Project and Lincoln Park Zoo: “It is often said that as we come to appreciate other societies’ cultures, the more likely we are to make conscious decisions to coexist in harmony. Having now been shown to be responsible for their decline, it is our species responsibility to change attitudes and policies that influence the fate of chimpanzees and their cultures before they disappear.”

Emma Stokes, WCS’s Central Africa Director said: “We risk destroying these forests before even discovering what secrets they hold. These findings reinforce the broader values of intact forests for climate and biodiversity.”

Deforestation, habitat degradation, poaching and disease are the main factors driving the disappearance of not only these diverse behaviors but chimpanzee themselves.

Increasing human encroachment and resource extraction in the form of selective logging across Africa are major drivers of such change. From 2000-2013, mechanized logging resulted in the loss of 77 percent of the intact forests across the continent.

Associated road expansion has exposed once isolated chimpanzee populations to new environmental risks. Nowhere in central Africa is the situation more concerning than in northern Republic of Congo which harbors 33 percent of Western Equatorial Africa’s closed canopy forest estate and 43 percent of remaining endangered central chimpanzee (Pan troglodytes troglodytes), according to recent study by the WCS. Roughly 27,000 km2 (10,424 square miles) forest are currently leased for logging surrounding the Nouabale-Ndoki National Park of the Tri-National de la Sangha (TNS) landscape – a (UNESCO) World Heritage site. 

The authors of the study say the findings underscore the need for expanding conservation policies. There is a place for cultural stewardship to play a role in increasing chimpanzee survival prospects, particularly in certified logging concessions like those bordering the Nouabale-Ndoki National Park.

The Forest Stewardship Council (FSC) requires adherence to practices that include protecting biological, environmental service, social and cultural values that are significant or critically important. “Sacred forests” and cultural heritage attributes such as particular trees are often conserved for local communities. Many of the same species valued by local indigenous communities are also important resources for chimpanzees, western lowland gorillas, and elephants. 

Long-term examination of chimpanzee material culture in the Goualougo Triangle study area shows a more holistic approach to identifying, managing, and monitoring these particular tree species is likely to deliver benefits not only to humans, but also the wildlife in the region.