By Bruce Bower
Chimpanzees living in central Africa’s dense forests have no access to a hardware store, but that doesn’t stop them from assembling their own brand of toolkits. These apes use as many as five homemade tools in set sequences to obtain honey from beehives located at least 20 meters high in the trees, in fallen tree trunks and up to 1 meter underground, according to two new studies.
Chimps living in Gabon’s Loango National Park modify tree branches of various lengths and widths to make complex tool sets for removing honey from the hives of different bee species, anthropologist Christophe Boesch of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and his colleagues report online May 19 in the Journal of Human Evolution. In other parts of Africa, chimps use only one or two tools at a time to obtain honey from hives, crack nuts or hunt small animals.
Near Loango, in a forested region of the Congo Basin called the Goualougo Triangle, another group of chimps also makes and uses different types of tools to open beehives and gather honey, say Crickette Sanz, also of the Max Planck Institute for Evolutionary Anthropology, and David Morgan of Lincoln Park Zoo in Chicago.
Chimps across Africa have developed regional tool-using traditions in honey gathering, Sanz and Morgan propose in the June International Journal of Primatology. In central African forests, hard-to-reach hives and competition for food with nearby gorillas have elicited complex forms of tool use by chimps, the researchers contend. That proposal challenges the traditional idea that advanced behaviors among human ancestors emerged only after they left the forest for wide-open savannas. Forest-dwelling ancestors could have achieved chimplike advances in tool-making as well, in Sanz and Morgan’s view.