Chimpanzees have a more elaborate and diversified material culture than any other non-human primate.
Their behavior varies in tropical Africa in a way that does not always correspond to ecology: for example, only chimpanzees in West Africa, but no other, use stone and wood hammers to crack nuts. in a number of populations, despite the great availability of hammers and hammers. appropriate nuts throughout the range of the species.
An understanding of the extent of this behavioral diversity is crucial to help researchers understand the likely emerging traditions of our own hominid ancestors.
Previously, several large-scale behavioral patterns in chimpanzees have been documented, including the use of clubs to pound hives in ruins in Central Africa and long tools for picking up algae at several sites in Africa. Where is. A team of researchers from MPI-EVA and the University of Warsaw now presents a detailed description of a new "behavioral domain" in Oriental chimpanzees (Pan troglodytes schweinfurthii) of the Bili-Uéré region, northern DR Congo. This set of behaviors covers at least 50,000 km² and possibly extends over an even larger area. "Over a 12-year period, we documented chimpanzee tools and artifacts in 20 areas of investigation and collected data on droppings, resting food, and sleeping nests," he said. principal author Thurston C. Hicks, visiting scholar at MPI-EVA and associate professor. at the Faculty of Liberal Arts of the University of Warsaw. "We describe a new toolkit for chimpanzees: long probes used to harvest epigeic ants (Dorylusspp.), short probes used to extract ponerine ants and arboreal nests from stingless bees, fine dip sticks for D. kohliand large dig sticks used to access the underground nests of meliponin. "
In addition, researchers are documenting expanded percussion technology associated with food processing: in addition to pounding hard-shelled fruit against substrates (seen in other chimpanzee populations), Uéré also crush two kinds of termite mounds, Cubitermes sp. and Thoracotermes macrothorax, a resource that chimpanzees in most other areas do not know. These chimpanzees, on the other hand, do not seem to exploit the common termite Macrotermes muelleri, for which chimpanzees fish on several other long-term research sites. "We have also documented tentative evidence of snail and giant tortoise snail pests against substrates, two new food resources for chimpanzees. Finally, nesting behavior on the ground is common throughout the region, "says Hicks.
Despite a general similarity of behavior on both sides of a major river (Uele) and in two very different types of habitats (mosaic of savannah and tropical forests in the north and tropical rainforests in the south), the team research has the behavior of chimpanzees, including different encounter rates for tools of the epigee driver ant, a lack of honey digging tools to the south; and long ant probes and fruit grinding sites north of the Uele River.
"Today, we can feel that we have already discovered everything there is to discover. What a nice surprise then to find a new behavioral kingdom for chimpanzees! It just shows that not everything has been traced yet and that we still have a lot to learn about the natural world, "says co-author Hjalmar Kühl, MPI-EVA ecologist and iDiv research center.
"In today's overdeveloped world, opportunities such as studying a large culture of intact, non-human great apes, interconnected over tens of thousands of kilometers of forest, are extremely rare," says Hicks. "We need such natural laboratories to understand how material culture is spreading among healthy and flourishing hominid populations. Without this, it may be difficult to envision the innovations made by our own ancestors in the forests of Africa millions of years ago.
Christophe Boesch, director of the MPI-EVA's Primatology Department and co-author of the study, said: "It's great to have found these fascinating behavior traits in this population. We simply hope that the many threats they face will not erase these chimpanzees as we learn more about their uniqueness. "
MAX PLANCK INSTITUTE OF EVOLUTIONARY ANTHROPOLOGY
Header Image – Drawing of an Oriental Chimpanzee (Pan troglodytes schweinfurthii) of the Bili-Uéré region in northern DR Congo. Credit: Cleve Hicks