Nov. 27 () –
Some of the most advanced behaviors seen in chimpanzees They may have been passed down and perfected over generations.
This is suggested by a new multidisciplinary study led by the University of Zurich on these animals, known for their remarkable intelligence and use of tools, aimed at analyzing whether their cultures also evolve over time, like human cultures.
In recent decades, scientists have clearly demonstrated that chimpanzees, like humans, pass on complex cultures, such as tool use, from generation to generation. But human culture has become much more sophisticated, from the Stone Age to the Space Age, as new advances have been incorporated. Chimpanzee cultures have not changed in the same way, suggesting that only humans have the remarkable ability to build more sophisticated cultures over time.
However, scientists who study chimpanzees in the wild have questioned this, suggesting that some of chimpanzees’ more complex technologies, in which they use multiple tools in sequence to extract hidden food sources, were probably built on prior knowledge. over time.
“As most chimpanzee tools, such as sticks and stems, are perishable, there are few records of their history that confirm this hypothesis, unlike human cases such as the evolution of the wheel or computer technology,” he says. in a statement lead author Cassandra Gunasekaram from the Department of Evolutionary Anthropology at the University of Zurich.
For the new study, a team of anthropologists, primatologists, physicists and geneticists from universities and research institutions in Zurich, St. Andrews, Barcelona, Cambridge, Konstanz and Vienna joined forces to trace genetic links between chimpanzee populations across thousands of years. of years, using new discoveries in genetics to uncover key pieces of chimpanzee cultural history.
The authors collected information on markers of genetic similarity (genetic evidence of links between different chimpanzee groups), as well as a variety of foraging behaviors previously reported to have been culturally learned, from a total of 35 chimpanzee study sites. throughout Africa. They grouped these behaviors into those that did not require tools; More complex behaviors that require simple tools, such as using a sponge to scoop water from a hole in a tree, and more complex behaviors that depend on a set of tools.
“As an example of this toolkit, chimpanzees in the Congo region first use a strong stick to dig a deep tunnel through hard soil to reach an underground termite nest,” explains Gunasekaram. “Next, they make a ‘fishing’ probe by pulling a long stem of a plant between their teeth to form a brush-like tip, pressing it into a point and deftly threading it through the tunnel they have made. “Then they take it out and nibble on the termites that defend themselves and have bitten it.”
“We have made the surprising discovery that it is chimpanzees’ most complex technologies – the use of entire ‘tool sets’ – that are most strongly linked between now distant populations,” says corresponding author Andrea Migliano, professor of evolutionary anthropology. at UZH. “This is exactly what would be predicted if these more advanced technologies had been rarely invented and if they had been even less likely to be reinvented, and therefore, “it would have been more likely that they would have been transmitted between groups.”
In chimpanzees, it is sexually maturing females, rather than males, who migrate to new communities to avoid inbreeding. In this way, genes spread between neighboring groups and then to more distant ones over years, centuries and millennia. The authors of the study discovered that these would be the same female migrations which They could spread any new cultural advances to communities that lacked them.
The study also showed that when both complex toolkits and their simpler versions (i.e. mainly toolkit components) are found at different study sites, genetic markers indicate that the sites were connected in the past by female migrations.
This suggests that the complex versions were built cumulatively by adding or modifying the simple ones. “These groundbreaking discoveries provide a new way to demonstrate that chimpanzees have a cumulative culture, albeit at an early stage of development,” adds Migliano.
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