Despite looking so similar – in fact it wasn’t until 1928 that scientists first realized they were separate species – bonobos and chimps differ in a number of important ways. Their societies are vastly different, as while chimps live in a male-dominated society and tend to settle conflict through aggression, bonobo males are subordinate to females and the species settles disputes through social interaction and sex.
Chimpanzees are also known to be prolific tool users, whereas bonobos only use a few. It was what drives this difference in tool use that interested Dr Kathelijne Koops from the University of Cambridge and the University of Zurich. What she found was that young chimps spend far more time playing with objects, whereas young bonobos spend this time interacting and socializing with other apes.
“Young chimpanzees spent much more time manipulating and playing with objects than young bonobos,” Kathelijne Koops, who authored the study published in Scientific Reports, told IFLScience. “The species difference in object manipulation was already apparent in very young individuals [< 1yr old], which strongly suggests that it is an intrinsic difference and not socially-facilitated.”
The difference between the two apes has always been a bit of a mystery. They look incredibly similar and share most of their genetics, and their ranges are separated only by the Congo River – yet their behaviors are strikingly disparate. Is their tool use related to the environments in which they live, or to their social interactions and chance to learn from other members of their community? Or is it something far more innate? It was these conflicting influences that Koops had to tease apart.
What she found was that they both live in incredibly similar environments, and that chimps have no extra opportunities to craft tools when compared to the bonobos. She then looked at whether chimps spend more time interacting with each other and thus increase their opportunities to learn tool-making abilities from one another. But she found that bonobos actually spend more time interacting and have more social partners than chimps.
Finally, she looked at how long the youngest members of each species spend playing with objects, not necessarily tools. She was shocked to find such a striking difference: that younger chimps are far more “object-minded” and spend far longer manipulating things compared to younger bonobos. This suggests that the difference in tool use between the species might be innate.
“Bonobos still have the ability to use tools, but they don't appear to have the same predisposition for tool use. In other words, they seem to lack the intrinsic motivation for tool use found in chimpanzees,” explained Koops. “One possibility is that there may be a trade-off between tool use motivation and social attention. This idea is supported by recent research on captive apes using eye-tracking techniques. Bonobos pay more attention to social cues, whereas chimpanzees pay more attention to the object in question.”
This discovery even has an impact on tool use within our own culture. The study suggests that manipulating tools was probably innate to the last common human/chimp/bonobo ancestor and that we ourselves are therefore predisposed to it. Koops hopes to look at different groups of chimps to see if the cultures observed in different communties are reflected in object manipulation rates and the likelihood of tool use.