Just like humans, it is socialization that shapes the vocabularies of orangutans.

A new study by researchers at the University of Warwick has found that great apes’ vocabulary changes during social interactions, and this shapes their ‘vocal personalities’. This discovery could constitute a major advance in the understanding of the evolution of language.

The study was published in the journal Nature Ecology and Evolution. It consisted in examining the social interactions of 70 orangutans belonging to six populations of Borneo and Sumatra, in Southeast Asia. Lead author Dr. Adriano R Lameira and his colleagues lived alongside the monkeys, enabling them to record calls and gather the largest sample of such voice recordings ever recorded, intended for the scientific research.

The study highlighted the palpable influence of social life in the evolution of language. In any case, this is what scientists have observed in great apes.

The effect of numbers

During the study, it was found that dense orangutan populations were home to more experimentation and vocabulary diversity. The animals used a wide range of original calls mixed with new sounds that could last or be dropped. Conversely, small populations living in a more scattered arrangement appeared to use a more restricted range of calls. Since there is less experimentation with new sounds in these groups, new noises tend to stick around once they are introduced. Thus, an individual’s complete repertoire is richer than that of a dense population that often drops new sounds.

For language to evolve, it is possible that social influence must exist as a means of agreeing on a fixed standard of communication within a population. This allows voice standards to become operational. Thus, if we could establish the exact moment when great apes began to pay attention and to be influenced by the vocalizations of other individuals, this would be a crucial step in understanding the origin of language.

Valuable information about the evolution of language

According to the authors, orangutans possess “vocal personalities”. As with humans, these can be shaped and influenced by interactions with other orangutans. These personalities then represent an intermediate stage between vocalizations and language in great apes. According to Lameira, great apes, whether in captivity or in the wild, are helping us understand the origin and evolution of language.

Unfortunately, these animals are threatened with extinction. According to the authors of the study, if we do not do more to protect our “living ancestors”, we risk losing valuable information. For Lameira, each population that disappears will take with it clues to the evolutionary history of our species.


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