Some chimpanzees use sticks to fish for termites
Manoj Shah/Getty Images
Wild chimpanzees seem to learn skills from each other and then, like humans, refine these techniques from generation to generation.
In particular, young females migrating between groups bring their own cultural knowledge with them, and groups can combine new and existing techniques to better forage. This “cumulative culture” means that some chimpanzee communities are advancing technologically over time, albeit very slowly, he says. In Andrew White at the University of St Andrews, UK.
“If chimpanzees have cultural knowledge that the community they’re moving to doesn’t have, they can pass it on, the same way they pass on genes,” he says. “And then that culture is built from there.”
Scientists knew that chimpanzees were able to use tools in sophisticated ways and pass this knowledge on to their offspring. But compared to the rapid technological development of humans, chimps didn’t seem to be improving on previous innovations, Whiten says. The fact that chimpanzee tools are made from biodegradable plants makes it difficult for scientists to follow their cultural evolution.
Cassandra Gunasekaram At the University of Zurich in Switzerland, he suspected that he would be able to apply genetic analysis to the puzzle. While male chimpanzees remain in their home range, young females leave their native communities to find mates elsewhere. She wondered if those women had brought their skill sets to the new teams.
To find out, he and his colleagues obtained data on 240 chimpanzees representing all four subspecies. previously collected by other research groups In 35 African learning centers. The data included detailed information about what, if any, tools each animal had and their genetic connections over the past 15,000 years. “Genetics gives us a kind of time machine for how culture was transmitted between chimpanzees in the past,” says Whiten. “It’s quite a revelation that we can have these new insights.”
Some chimpanzees used complex combinations of tools, such as a digging stick and a fishing brush made by pulling a plant stem between their teeth, to hunt termites. The researchers found that chimpanzees with the most advanced tool sets were three to five times more likely to share the same DNA than those with simple tools or no tools at all, even when they lived thousands of miles apart. And the use of advanced tools was also more associated with female migration compared to the use of simple or no tools.
“Our interpretation is that these complex toolkits may have been invented by building on an earlier, simpler form, and therefore must have depended on transmission by women from the communities where they were originally invented to other communities along the way,” she says. peel off
“It shows that complex tools would be based on social exchanges between groups, which is very surprising and exciting,” says Gunasekaram.
Thibaud Gruber The University of Geneva is not surprised by the results, but says the definition of complex behavior is controversial. “After 20 years of working with chimpanzees, I would say that the use of the stick itself is complex,” he says.
His team, for example, found what they called cumulative culture in chimpanzees that make sponges out of moss instead of leaves, which is no more complex, but it works more efficiently by absorbing mineral-rich water from clay deposits. “It’s not about being more complex, it’s about having a technique that builds on a previously established technique,” he says.
Accumulated culture is still significantly slower in chimpanzees compared to humans, probably because of different cognitive abilities and lack of speech, says Gunasekaram. Additionally, chimpanzees interact much less with others outside their community compared to humans, giving them less opportunity to share culture.
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