In yet another experiment that adds to the ever-mounting evidence that humans aren’t special at all, scientists at the University of Haifa in Israel have observed bonobos making stone tools on par with those made by early humans.
Bonobos, along with chimpanzees, are human’s closest living relatives. Those two apes make up the genus Pan, while humans are in the genus Homo. Chimpanzees are known tool-users, but bonobos aren’t known for this. However, in captivity, they have been known to bash some rocks together. Two of the bonobos in this current study — Kanzi and Pan-Banisha – were taught to make stone tools in the 1990s, but it looks like Kanzi has been doing his homework because he proved to be a brilliant problem solver. According to Phys.org:
The researchers challenged Kanzi and Pan-Banisha to break wooden logs and to dig underground, tests similar to tasks the apes might have to carry out to get food in the wild. To break the logs — an act similar at cracking open bones to get at marrow — the scientists not only saw these apes use rocks as hammers or projectiles to smash their targets, but also observed them either rotating stone flakes to serve as drills or use the flakes as scrapers, axes or wedges to attack slits, the weakest areas of the log. To root into hard soil, these bonobos used both unmodified rocks and a variety of handmade stone tools as shovels.
Both bonobos used tools, but Kanzi’s are different. They aren’t just any tools. These are tools that have the hallmarks of the tool categories of early Homo: wedges and choppers, and scrapers and drills. The last common ancestor of humans and bonobos may have had this capability, which means the use of stone tools would predate Homo. This is significant. This new observation further questions when Homo culture began. It questions where we fit in the tree of life.
Researchers were quick to point out that Kanzi, the breakout star of this experiment, is no ordinary bonobo. He was raised around humans and has had constant interactions with people. The researchers studied five other bonobos and none of them created stone tools, although there were a few wooden tools or unmodified rocks used as hammers. Even Pan-Banisha only used a few stone tools for digging.
So it’s hard to say what significance this has on bonobo intelligence as a group. Since both Kanzi and Pan-Banisha were taught to make tools in captivity, it’s unclear whether these tools would be seen in the wild, but the potential is there. It’s likely that our early ancestors had the mental capacity to make stone tools. It’s an exciting new chapter in the story of our evolutionary family tree. You can watch a video of this remarkable ape and his stone tools via The Guardian.
Image credit: Alaina Abplanalp Photography