Orangutans adapt their vocabulary to the social environment, like humans

A team of researchers has shown that wild orangutans do not have a fixed language, but they use different vocal registers and adapt them to the social group with which they live or communicate.

According to an article from the University of Warwick (England), published today in the journal Nature Ecology & Evolutionsocial interaction shapes and transforms the “vocabulary” of apes, just as it happens with humans.

This finding not only demonstrates that wild orangutans have different “vocal personalities”, but, according to its authors, draws a direct parallel between our development and that of our evolutionary ancestors.

To do the study, Warwick Psychology Department researcher Adriano R. Lameira and his team, recorded the calls of about seventy apes from six populations of orangutans from the swamps and jungles from Borneo and Sumatra in Southeast Asia, the largest sample ever analyzed in a study of the vocal behavior of great apes.

These orangutan populations differed in their population density, from groups that socialized intensely to those that were more dispersed.

In those of high density, the orangutans used a great variety of original calls and tried a multitude of sound variants that they constantly modified or abandoned, while the specimens of the more dispersed populations and with lower density opted for more established and conventional calls.

Although the more dispersed groups did not experiment with such a large number of novel sounds, when they introduced a new call variant they retained it, and thus their call repertoire was richer than that of orangutans in high-density populations, which continually discarded new variants of calls.

If orangutan call communication is socially shaped, it is likely to be the case for our direct and extinct ape ancestors as well, the authors say.

Language, affected by social influence

The study suggests that social influence – although predictably modest at first, before the emergence of a fully functioning primitive language – could have steadily increased, eventually giving rise to the myriad ways in which language is determined by those around us.

“Great apes, both in the wild and in captivity, are finally helping us solve one of the oldest puzzles in science: the origin and evolution of language”comments R. Lameira.

“We can now begin to envision a gradual path that probably led to the rise of the talking ape, us, rather than having to attribute our unique verbal abilities and advanced cognition to divine intervention or chance genetics,” he explains.

The researcher is convinced that orangutans can offer “many more clues in the life of our closest living relatives”although for this it is necessary to “guarantee their protection and conservation in nature”.

“Each population that disappears will take with it irretrievable glimpses of the evolutionary history of our species,” he warns. (I)