A bonobo eats food in Lola ya Bonobo in the suburbs of Kinshasa, capital of the Democratic Republic of Congo (DR Congo), Aug. 23, 2010. (Xinhua/Liu Chan)
A study published Tuesday in American journal PLOS Biology showed that two closely related great ape species, the bonobo and chimpanzee, used gestures that share the same meaning.
Researchers from the Universities of York, St Andrews, and Kyoto observed various behaviors such as a bonobo presenting its arm in front of a second bonobo and the second bonobo would respond by climbing onto the first bonobo's back.
If the first bonobo then stopped gesturing, it suggested the reaction from the second bonobo was the correct one. From this the researchers were able to infer that this single gesture meant "climb on me."
Taken over many observations, researchers were able to systematically define the sets of meanings of 33 bonobo gesture types and compare them to gesture meanings already known for chimpanzees.
It appears that many gesture meanings are shared by both species, which were separated approximately 1 to 2 million years ago, and perhaps may have also been shared by the last common ancestor of those apes and human beings.
Kirsty Graham, research associate at the University of York's Department of Psychology, said: "The overlap in gesture meanings between bonobos and chimpanzees is quite substantial and may indicate that the gestures are biologically inherited."
"We are also starting to examine whether humans share any of these great ape gestures and understand the gesture meanings," Graham said.
