We have identified well over a hundred different gestures used by chimpanzees, more than enough to reveal the primates use nonverbal communication much like we do. But it's what the chimps are saying with their hands that's truly fascinating.
Dr. Anna Roberts of the UK's Stirling University spent months in Uganda studying the hand gestures used by chimpanzees to communicate with each other. She identified about 20 to 30 gestures that dealt with concepts from nursing and feeding to fighting and aggression, plus a bunch to do with sex. While these findings aren't exactly new — other researchers have identified over a hundred such gestures in chimps and other primates over the past few years — what sets this new data apart is how so many of the chimps' gestures resemble those of humans.
Dr. Roberts found that at least a third of the chimps' gestures were similar to those of humans and meant broadly the same thing. Chimps will use what we would recognize as a begging gesture to get others to give them food, they clap their hands together when excited, and when they want another chimp to approach them, they make what we would instantly recognize as a beckoning gesture.
It's enough to suggest that these gestures are not simply evolutionary coincidence, that they actually share a common origin with the similar signs used by humans. And, of course, the only way that could work is if these gestures date all the way back to the evolutionary common ancestor of humans and chimpanzees, which lived at least six million years ago. Dr. Roberts explains in a statement from the University of Stirling:
"Chimpanzees use these gestures intentionally to elicit a desired response from other chimpanzees and they may be the missing link between ape and human communication. We now know that these gestures must have been in the repertoire of our common ancestor and might have been the starting point for language evolution. Manual gesture in chimpanzees is controlled by the same brain structures as speech in the human brain."
And it isn't just that chimpanzees happen to move and contort their hands in ways similar to how humans do. Rather, it's that these gestures form part of a larger communication apparatus that is strikingly like how we interpret each other's nonverbal communication, as Dr. Roberts explains:
"Chimpanzees not only use similar manual gestures to humans, but the way they use these gestures is also very similar to the way humans gesture and use language. The defining way that people understand communication with others is by figuring out what someone really means by ‘mind-reading' their intentions and we have discovered that chimpanzees may have a similar ability...The ability to co-operate and learn from others paved the way for language evolution. If chimpanzees learn the precise structure of their gestures from others, this means that the fundamental cognitive skills required for language evolution are already present in our closest living relatives."