While sending your friends memes on the internet might be the most popular form of communication in 2022, this trait – sharing for sharings sake – was thought to be a social behavior unique to the human race. Now, researchers have discovered that same behavior in wild chimpanzees.
Footage of an adult female chimpanzee called Fiona showing a leaf to her mother, Sutherland, has been captured by researchers from the universities of York and Warwick. This footage was filmed in Kibale Forest in Uganda. This social behavior leads the team to suggest that chimpanzees are able to share experiences with each other and, using gestures, make a comment on the things around them.
Human children begin using this behavior within the first year of their lives but chimpanzees have never been observed doing the same until now. These moments are known as referential gestures and up until this point have always been in a manner to request something, rather than just for the sake of sharing.
“We observed an adult chimpanzee showing her mother a leaf she had been grooming, not because she wanted her to do anything with the leaf, but most likely because she simply wanted her to also look at the leaf,” said lead author of the study, Dr Claudia Wilke from the Department of Psychology at the University of York, in a statement.
Chimpanzees are highly social and are known to engage in leaf grooming behavior whereby they pluck leaves from nearby trees and groom them with their mouths or fingers. The reasons for this are unclear but could be related to ectoparasites they have removed during the grooming process.
The team looked at 84 instances of similar events to rule out other possible reasons for the behavior, including playing. They concluded that the leaf was not given to Sutherland to eat as this species of plant does not form part of the chimpanzee diet in this area. The team now plan to look at other chimpanzees to see if they engage in the behavior and explore this in relation to human social cognition.
“Our observations raise new questions about why humans share experiences more often than our closest living relatives and whether engaging in this behavior at a higher frequency than other species can still explain the evolution of cognitive functions underpinning human social behavior,” said co-author, Professor Slocombe from the University of York.
The paper is published in PNAS.