Bonobos and humans may have more in common than we think.
A new Israeli study has found that the endangered bonobo (a type of chimpanzee) is capable of making and using tools to solve problems. And while individual apes in captivity have been known to use basic tools, this study shows that they can also make more advanced tools and that this capacity is more prevalent than previously believed.
In an effort to better understand how ancient humans (also called hominins) came to be the earliest tool users in the Paleolithic era, about 2 million years ago, the research team studied a group of male and female bonobos. The results were surprising.
For the study, led by University of Haifa researcher Itai Roffman, the team observed how two populations of captive and semi-captive bonobos in Germany and the US responded to a series of food extraction challenges that were set up. For one challenge, the researchers would show the bonobos that food was buried under rocks at an open field site, and then place natural materials like deer antlers, sticks, and stone tools nearby for potential use. “These were effectively used as mattocks, daggers, levers and shovels,” according to the study, which was recently published in the American Journal of Physical Anthropology.
In a different challenge, the researchers hid food in the cavities of dry long bones to see how the bonobos would extract it. One bonobo was seen bisecting a bone by striking it successively with an angular hammer stone.
“She jabbed at me with her spear”
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Especially remarkable was how a few bonobos modified short and long branches to serve specific purposes. One bonobo fashioned spears from long branches with her teeth. “She jabbed at me with her spear to prevent me from writing my notes and to bar me from going to different sites. If I didn’t dodge, I could have gotten hurt,” Roffman tells NoCamels. “But it’s remarkable, because this kind of behavior has been regarded as a uniquely early human trait until now.”
Of the 15 bonobos studied, seven made use of tools. “My main excitement was not about the fact that they were using tools, but rather about the complexity of the tool use,” Roffman says. “It surprised me that the bonobos were using the same strategies and same sequences of action with the tools that early hominins did in similar contexts to achieve the mission of extracting food.”
A handful of scientists, however, have criticized the study, pointing out that the behavior of animals in captivity differs from that of their counterparts in the wild; mainly, that captive bonobos have more time to experiment with tools in a secure environment. Roffman plans to respond to this criticism with new data that he has accumulated from his field study on wild chimpanzees in West Africa. He declined to further comment until the new data is published.
Rebuilding the cultural traditions of apes
Will apes take over the world in a few years? Probably not. Yet, Roffman believes his study carries important ethical implications. “Hopefully, this study will show that zoos are not suitable for chimpanzees and bonobos – our sister species,” Roffman says. “At least they should be kept in semi-captivity, open spaces with natural raw materials where they can rebuild their cultural traditions and express their potential, which resembles that of early hominins.”
In the future, Roffman hopes to establish cultural rehabilitation sanctuaries in Israel and in Africa to rethink the way apes are kept in captivity.