Two orangutans in captivity have sown that they can use stone tools. But they can’t make them.
The observation is important because these orangutan cousins live in the trees, and rarely encounter rocks and stones. The pair of relatives, who live in the Ktistiansand Zoo in the south of Norway, were given a box by researchers. The box contained a piece of fruit The box was tied up with a rope. The orangutans were also given several stones. The stones were chosen because in theory it was possible to sharpen them to make them more cutting, so they could cut the rope and get at the fruit.
Though this task seemed too complex for our orangutans, they used the rocks to hit the box, a behavior the researchers judged as “interesting,” because it was not something they would do in the wild. Better, when researchers gave them stones that were already edged for cutting, one of the orangutans used theirs to cut the rope and open the box to get at the fruit. It was the first observation of that behavior in an orangutan.
Did they imitate the humans they’re in contact with at the zoo, or would they have done the same thing in nature with a sharp stone? The answer remains cloudy, but it brings us back millions of years, when some of our ancestors would have realized that they could use stones, and even improve their shape.
Orangutans and our ancestors diverged 13 million years ago.
For a link to the original article: https://www.sciencepresse.qc.ca/actualite/2022/02/21/orang-outan-peut-apprendre-decouper
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