CAMBRIDGE, Mass., June 3 (UPI) -- Chimpanzees understand the idea of placing raw food into a device, waiting a few minutes, and then receiving a more delicious piece of cooked food, according to a new study.
Harvard University researchers gave wild-born chimpanzees at the Jane Goodall Institute's Tchimpounga Chimpanzee Sanctuary in the Republic of Congo a "cooking device" that turned raw sweet potato into cooked sweet potato, and another device that did nothing. The chimpanzees figured out which was which, and when given the choice nearly every chimp decided to eat the cooked food.
The device was not actually cooking food; researchers were merely replacing the raw potatoes with cooked potatoes after about a minute.
But the real test came when the chimps were given a raw potato, and the option to place it in the cooking device. Animals are known to have lower self control when in possession of food, and researchers believed the chimps would simply eat the potatoes raw. Instead, about half the chimps chose to put their raw potatoes in the cooking device.
Further testing showed the chimpanzees also have a willingness to carry food over a distance -- from one side of an enclosure to the other -- in order to cook it.
The chimps were then given a raw potato and a piece of wood, and only put the potatoes in the cooker, demonstrating they understood the process was a transformation, and not simply a trade.
Researchers say the study demonstrates an important step before humans discovered how to control fire.
"It is an important question when cooking emerged in human evolution," said Felix Warneken, the John L. Loeb Associate Professor of the Social Sciences at Harvard, in a press release. "We thought one way to get at this question is to investigate whether chimpanzees, in principle, have the critical cognitive capacities for cooking. If our closest evolutionary relative possesses these skills, it suggests that once early humans were able to use and control fire they could also use it for cooking."
The study is published in Proceedings of the Royal Society B.