Social mixing shapes and transforms the “vocabulary” of apes, just as it does in humans, a new study from the University of Warwick has found. Scientists have found that, unlike a fixed repertoire of instinctive, automated calls, wild orangutans show evidence of distinct “vocal personalities” that are shaped by the social groups in which they live and communicate.
Living alongside orangutan communities in the low forests and swamps of Borneo and Sumatra in Southeast Asia, the researchers recorded the calls of about 70 individual monkeys in six populations. These populations naturally differed in density, ranging from groups that socialized intensely to more dispersed groups.
In high-density populations, monkeys communicated using a wide variety of original calls, continually trying out many new sound variants that were often modified or even abandoned altogether.
In contrast, orangutans living in sparser, low-density populations showed a preference for more established conventional calls. Although these groups do not experiment with so many new sounds, when they introduce new call variants they tend to retain them, making their repertoire richer than that of monkeys living in high-density populations. .
These results suggest that communication was also socially shaped in the case of our direct, extinct ape-like ancestors. This kind of social influence – though modest at first, before the rise of fully operational languages – could then have steadily increased, eventually leading to the variety of ways in which human language is determined by those around us.
“Great apes, both in the wild and in captivity, are finally helping us solve one of science’s oldest puzzles – the origin and evolution of language,” said the lead author. the study, Dr Adriano Lameira, assistant professor of psychology at the University of Warwick. “We can now begin to design a gradual path that likely led to the rise of the talking monkey, us, instead of having to attribute our unique verbal skills and advanced cognition to divine intervention or a random genetic jackpot.”
“Many more clues await us in the lives of our closest living relatives, as long as we manage to ensure their protection and preservation in the wild. Each population that disappears will take with it irrecoverable glimpses of the evolutionary history of our species,” Professor Lameira concluded.
The study is published in the journal Nature ecology and evolution.
By Andrei Ionescu, Terre.com Personal editor