Orangutans Reveal Ability to Use Stone Tools

Anthropologists and philosophers may never agree on where along the evolutionary path we became human, but tool use probably had something to do with it. For years, scientists believed only humans used tools, but now we know tool use happens here and there in the animal kingdom. Orangutans are known for making use of what’s around them, but how close are they to the Stone Age? Turns out, maybe closer than you think. A study undertaken at Norway’s Kristiansand Zoo and the Twycross Zoo in the UK shows that untrained Orangutans can make use of stone tools.

Orangutans have been observed in the wild using simple tools like sticks to collect insects and leaves to shield them from the elements. There’s even a famous photo of an ape hanging from a tree trying (and failing) to spear fish. Discoveries like these forced us to reevaluate whether or not tool use is uniquely human. The more we look into it, the less special we are. However, orangutans have not been observed using stone tools, but the new research suggests it could just be only a matter of time.

At the Kristiansand Zoo, researchers explored the apes’ ability to use stone hammers and sharp flint flakes. A hammer is essential to making other tools by splitting apart other rocks. The animals did use the stolen hammer but not to hit other rocks — they mostly smacked the wall of their enclosure. While they could not make their own flint flakes, they did use one to cut open a silicone skin to access food.

The part of the study in England tested the orangutans’ ability to learn tool use by observation. The researchers showed the apes, among them one that goes by Molly, how to strike a rock with a hammer stone to create a flint flake. It took a while, but Molly picked up the stone and struck the right part of the flint. The impact did not produce any fragments useful as tools, but some of the small “byproduct” pieces were sharp enough to cut rope.

The researchers believe that orangutans have the ability to use simple stone tools, but for some reason, they don’t develop this skill in the wild. The main barrier to an orangutan stone age may be less what they can do and more where they live. Orangutans are mainly arboreal, and all the rocks are down at ground level. Of course, our ancestors were believed to be arboreal before we started all this walking upright nonsense. Maybe orangutans are just waiting for their moment.