Wild chimpanzees appear to learn from each other and then – just like humans – improve these techniques from one generation to the next.

In particular, young females that migrate between groups bring with them their cultural knowledge, and groups may combine new techniques with existing ones to improve their foraging. Such “cumulative culture” means that some chimpanzee communities become more technologically advanced over time – albeit very slowly, he says. Andrew Whiten at the University of St Andrews, UK.

“If chimpanzees have cultural knowledge that the community they move into doesn’t have, they can pass it on – the same way they pass on their genes,” he says. “And then that culture builds from there.”

Scientists already knew that chimpanzees were capable of using tools in sophisticated ways and passing this knowledge on to their offspring. But compared to humans’ rapid technological development, it seems that chimpanzees are not progressing on previous innovations, Whiten says. The fact that chimpanzees’ tools are often made from biodegradable plants makes it difficult for scientists to track their cultural evolution.

Cassandra Gunasekaram at the University of Zurich in Switzerland suspected she might be able to apply genetic analysis to the puzzle. While male chimpanzees stay in their home region, young females leave their home community to find mates elsewhere. She wondered if these women had brought their skills with them to their new groups.

To find out, she and her colleagues acquired data on 240 chimpanzees representing the four subspecies, which were previously collected by other research groups across 35 study sites in Africa. The data included precise information on what tools, if any, each of the animals used, as well as their genetic connections over the past 15,000 years. “Genetics gives us a kind of time machine for how culture was passed down to chimpanzees in the past,” Whiten says. “It’s quite a revelation that we can have this new knowledge.”

Some chimpanzees used complex combinations of tools, for example a drilling stick and a fishing brush made by pulling a plant stem between their teeth, to hunt termites. Researchers found that chimpanzees with the most advanced tools were three to five times more likely to share the same DNA as those who used simple tools or no tools at all, even if they lived thousands of miles away . And advanced tool use was also more strongly associated with female migration compared to simple or no tool use.

“Our interpretation is that these complex tool sets were actually invented perhaps building on an earlier simpler form, and therefore must depend on transmission by women in the communities that developed them. initially invented to every other community along the way,” Blanchir explains.

“This shows that complex tools would rely on social exchanges between groups, which is very surprising and exciting,” says Gunasekaram.

Thibaud Gruber at the University of Geneva is not surprised by the results, but says the definition of complex behavior is questionable. “Having worked with chimpanzees for 20 years, I would say that the use of sticks itself is complex,” he says.

Her own team, for example, discovered what they call cumulative culture in chimpanzees, which makes sponges from moss instead of leaves – which is not more complex, but works more efficiently to absorb mineral-rich water from clay pits. “It’s not about being more complex, it’s just about having a technique that builds on an already established technique,” ​​he says.

Cumulative cultivation is still significantly slower in chimpanzees than in humans, likely due to their different cognitive abilities and lack of speech, Gunasekaram says. Additionally, chimpanzees interact much less with others than humans, giving them fewer opportunities to share their culture.