Our cousins chimps and bonobos use similar sign languages
Posted in 28/02/2018
Chimp gestures are relatively-well understood (Photo: St. Andrews University)
Kirsty Graham, of the University of York, UK, and her team determined the meaning of 33 different gestures made by bonobos, and compared them with those made by chimpanzees.
The two species diverged from each other at least a million years ago, but the team found that the their gestures are more similar than would be expected by chance. “Bonobos and chimpanzees share not only the physical form of the gestures, but also many gesture meanings,” they say.
This may suggest that primate gestures are at least partially determined by biology. The team plans to investigate whether humans also share some of these gestures.
Read my body language
While chimpanzee gestures have been well studied, less is known about those of bonobos. The team determined the meaning of each of the gestures by observing the reactions they produced in other individuals.
For example, an arm extended in front of another bonobo was found to mean “climb on me”. As in chimpanzees, bonobos ask each other to start grooming by loudly scratching their arms. Like chimps, these primates stroke their mouths to tell each other to go get an object.
Chimpanzees and bonobos do not normally encounter each other in the wild. Bonobos are well-known for displaying compassion and empathy, and the importance of sex in their society.
The bonobo gesture to suggest sex – standing on two legs – was unique to their species, and not shared by chimpanzees.