Chimps share tools when tasks gets tough

Wild chimpanzees are more likely to share termite gathering tools with novices when the task involves greater complexity, according to a study published in the journal Proceedings of the National Academy of Sciences.

This tool sharing, known to be an important teaching method in chimps and humans, could offer insights into the growth of hominin tool technologies, a hallmark of human evolution, the authors suggest.

It’s commonly thought that non-human primates learn tool skills by watching others and then practising by themselves, notes first author Stephanie Musgrave from the University of Miami, US.

However, this study suggests social learning could vary according to how challenging the task is, providing new insights into cultural skill transfer of primates that share a common ancestor with humans.

“First, chimpanzee populations may vary not only the complexity of their tool behaviours but in the social mechanisms that support these behaviours,” Musgrave says.

“Second, the capacity for helping in chimpanzees may be both more robust and more flexible than previously appreciated.”

The researchers, in collaboration with the Wildlife Conservation Society, Lincoln Park Zoo and the Jane Goodall Institute, observed two populations of wild chimpanzees (Pan troglodytes) sharing tools for gathering termites – a popular, nutrient-rich snack.

Chimps are one of the most innovative group of tool users in the animal kingdom but there are regional differences in the complexity of their instruments for harvesting the tasty insects.

Residents of Gombe, Tanzania, use probes fashioned from various plant materials to gather termites from their complex nests beneath the ground; they stick the tool in, pull it out, and gobble up the insects that have clung onto it. 

Resourceful chimps from Goualougo, Republic of Congo, have created a more complex range of customised tools with brush-like tips that snare a bigger feast.

The researchers compared tool sharing between the two groups using standardised methods, holding constant other influences on helping behaviour such as intrinsic motivation and opportunity for request.

They found the rate of tool transfer was three times higher at Goualougo, and mums were far more likely to give one to their offspring when asked.

The differences suggest that teaching may be related to the complexity of learning to make tools, says co-author Crickette Sanz from Washington University, US.

“An increased role for this type of social learning may thus be an important component of the transmission of complex tool traditions over generations,” she adds.

Technological innovation in humans is attributed to skill-sharing through mechanisms such as teaching and imitation. This study could shed light on the evolutionary origins of these prosocial behaviours, says Musgrave.

“Our research shows that the human propensity to assist others in acquiring complex skills may build at least in part upon capacities that we share with our closest living relative.”

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