If a bonobo and a chimpanzee ever crossed paths, they’d probably be able to understand each other, according to research published on Wednesday.
Although it has been known for some time that bonobos and chimps perform a number of similar gestures, this is the first time that the meaning of those gestures has been found to significantly correlate.
In the article published in PLOS Biology, the researchers hypothesise the communication similarities could be a relic from the most recent common ancestor the great apes share with humans.
Despite bonobos and chimps diverging between one and two million years ago, researcher Kirsty Graham says it isn’t surprising that the meaning of their gestures remain similar.
“Bonobos and chimpanzees still need to communicate about many of the same things, their ecology hasn’t changed a great deal,” she said.
They analysed more than 2000 individual gestures performed by bonobos, which fell into 33 gesture types, and elicited 14 different reactions from the recipient, which they called “apparently satisfactory outcomes” (ASO).
ASOs were designated when a bonobo would cease gesturing after it received a response from its intended audience.
They compared those gestures and ASOs with research previously done on chimpanzee communication.
Between 88 and 96 per cent of the gestures performed by bonobos are also used by chimpanzees.
“We now know that there is also a large overlap in the intended outcomes achieved by these shared gesture types,” they state in the paper.
A bonobo, a chimpanzee and a human walk into a bar …
Given that bonobos and chimpanzees are our closest relatives, the researchers suggest there may be similarities in our own gestures as well.
They say that more research is needed to establish whether the language was present before we split into separate species, or if it’s a case of convergent evolution after we split – where the same attributes evolve independently of one another.
“If we can now discover whether humans also share or understand these great ape gestures, those two possibilities can be resolved,” they say.
They have already begun collecting preliminary data.
“We have just finished running an online experiment where we show people videos of chimpanzee and bonobo gestures and ask them to say what the gestures mean,” Ms Graham said.
“So far our results are looking promising, but that’s all I can say for now. Watch this space.”
Of the 14 “meanings” they were able to identify from the gestures, 12 were used to initiate or develop an activity, and two were commands to stop.
The majority of meanings were focused around mating and grooming, as well as food and requests to “follow me”, “move away”, and “climb on me”.
Gorilla and orangutan gestures also similar
Their fieldwork was based in Wanda in the Democratic Republic of Congo (DRC), which they accessed via a remote airstrip and dirt tracks.
“The hardest days [were] when the bonobos decided to go to the swamp,” Ms Graham said.
“They tend to [take off] in a straight line through the forest, down a hill, across streams, into the swamp and we’d try our best to keep up with them.”
Previous studies have found that some species are able to understand information conveyed in the calls of other species.
West African Diana monkeys and Campbell’s monkeys for example, respond to each other’s warning calls and can tell the difference between crowned eagle and leopard warnings, according to a study in Proceedings of the Royal Society.
Gorillas share 60 per cent of their gestures, and orangutans 80 per cent of their gestures with chimpanzees, but it hasn’t been established yet whether the meanings conveyed by those gestures are the same, as in the case of the bonobo.