13:09 21 August 2012 by Hannah Krakauer
Kanzi the bonobo continues to impress. Not content with learning sign language or making up “words” for things like banana or juice, he now seems capable of making stone tools on a par with the efforts of early humans.
Even a human could manage this (Image: Elizabeth Rubert-Pugh (Great Ape Trust of Iowa/Bonobo Hope Sanctuary))
Eviatar Nevo of the University of Haifa in Israel and his colleagues sealed food inside a log to mimic marrow locked inside long bones, and watched Kanzi, a 30-year-old male bonobo chimp, try to extract it. While a companion bonobo attempted the problem a handful of times, and succeeded only by smashing the log on the ground, Kanzi took a longer and arguably more sophisticated approach.
Both had been taught to knap flint flakes in the 1990s, holding a stone core in one hand and using another as a hammer. Kanzi used the tools he created to come at the log in a variety of ways: inserting sticks into seams in the log, throwing projectiles at it, and employing stone flints as choppers, drills, and scrapers. In the end, he got food out of 24 logs, while his companion managed just two.
Perhaps most remarkable about the tools Kanzi created is their resemblance to early hominid tools. Both bonobos made and used tools to obtain food – either by extracting it from logs or by digging it out of the ground. But only Kanzi’s met the criteria for both tool groups made by early Homo: wedges and choppers, and scrapers and drills.
Do Kanzi’s skills translate to all bonobos? It’s hard to say. The abilities of animals like Alex the parrot, who could purportedly count to six, and Betty the crow, who crafted a hook out of wire, sometimes prompt claims about the intelligence of an entire species. But since these animals are raised in unusual environments where they frequently interact with humans, their cases may be too singular to extrapolate their talents to their brethren.
The findings will fuel the ongoing debate over whether stone tools mark the beginning of modern human culture, or predate our Homo genus. They appear to suggest the latter – though critics will point out that Kanzi and his companion were taught how to make the tools. Whether the behaviour could arise in nature is unclear.
Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1212855109