Orangutans that hang out with other monkeys sound more original than those that are not as social.
It shows a new study by an English research group that investigated wild orangutans' communication.
- This connection indicates that the sounds of the orangutans are not congenital but are influenced by social factors.
There is another similarity between monkeys and humans, says Gabriela-Alina Sauciuc who is a researcher in cognitive science at Lund University.
Dialects in the monkeys
Researchers have studied monkeys on the islands of Borneo and Sumatra in Southeast Asia and listened to their so-called "kiss squeak" sounds.
The sound is similar to a kiss sound and is used as a warning signal or as a way for the monkeys to signal irritation and frustration.
Gabriela-Alina Sauciuc herself has studied orangutans and their behaviors.
- It was known that there were local variations in the sounds of the orangutans, that they could have dialects.
But this study indicates that the population density, in other words how many orangutans stay regularly in an area, can affect the monkeys' sounds, says Gabriela-Alina Sauciuc.
Social networks
Unlike chimpanzees and many other monkeys that live in flocks, orangutans live alone or in pairs.
Although they do not spend close time with each other, they often live in the same area as other orangutans.
The monkeys communicate and interact when they encounter each other and form social networks in the areas they live in. Sumatra orangutans live in larger social networks than the borneo orangutans and the new study shows that the sumatra orangutans' "kiss squeak" sounds vary more between individuals than among the borneo orangutans.
- What can happen in societies with higher population density is that an individual associates with several other individuals and is exposed to a larger number of variants of sounds.
It affects learning if you have several sounds to learn and can explain the trend of originality among sumatra orangutans, says Gabriela-Alina Sauciuc.
Man's speech ability
Mingling with other orangutans is thus important for the orangutans' language ability, just as social contexts affect the way people communicate.
Gabriela-Alina Sauciuc explains that the new information about human apes' communication can help us get a better picture of human evolution.
- If one finds any similarities between monkeys and humans, one can conclude that a certain trait has existed for a very long time during our evolution.
Then you can try to reconstruct how the language ability has developed, says Gabriela-Alina Sauciuc.