Chimpanzees not only love their sweet potatoes roasted and hot, they also have the brainpower needed to cook food, new research has found.
The findings suggest that cooking abilities emerged early in human evolution, and that aside from control of fire, chimps may possess all the requisite cognitive skills to engage in cooking.
"What is particularly interesting about cooking is it's something we all do, but it involves a number of capacities that, even without the context of cooking, are thought to be uniquely human. That is why we wanted to study this in chimpanzees," explained Felix Warneken from Harvard University.
To get at those questions, the researchers travelled to the Jane Goodall Institute's Tchimpounga Chimpanzee Sanctuary in Republic of Congo in the summer of 2011.
They conducted a series of experiments using wild-born chimpanzees to test whether they were capable of making the mental leaps necessary for cooking.
Their first tests were dedicated to replicating the results of other studies: demonstrating that chimps preferred sweet potato that had been "cooked" - placed in a hot pan, without butter or oil, for one minute - to raw.
Next, he researchers presented chimps with two devices - a "cooking device" that turned raw into cooked slices and a control device that left it unchanged.
Nearly every chimp reliably picked the cooking device, suggesting they quickly understood the transformation that was at work.
The researchers also found that a number of chimps, when given a raw piece of potato, chose to essentially cook it by placing it in the "cooking device" and receiving a cooked piece of food in return.
"The first time one of the chimps did this, I was just amazed," study co-author Alexandra Rosati from Yale University said.
"I really had not anticipated it. When one of them did it, we thought maybe this one chimp is just a genius, but eventually about half of them did it," Rosati pointed out.
The study was published in the journal Proceedings of the Royal Society B.
