Subsequent experiments showed the chimps understood the concept of cooking. These involved using a "cooking device" - a plastic tub with a false bottom that contained a piece of pre-cooked food.
The researchers would place aidentical piece of raw food into the tub, shake it, open the false bottom and present the chimp with the cooked food. To a watching chimp, it looked as if the tub was transforming the food from raw to cooked.
Chimps that had seen this done, were given a piece of raw potato and offered the choice of placing it in the "cooking device", putting it in similar tub that didn't do any "cooking", or eating it immediately. Many of the animals tried to "cook" their food, the Royal Society journal Proceedings B reports.
Researcher Dr Alexandra Rosati said: "The first time one of the chimps did this, I was amazed. I really had not anticipated it. When one of them did it, we thought maybe this one chimp is a genius but eventually about half of them did it."
Further experiments showed the chimps to try to "cook" carrots - but not a vegetable-sized piece of wood. They were even willing to carry food across their cage and wait to "cook" it. Two saved nearly every piece of raw food they were given, to "cook" later.
The results suggest many of the mental skills needed to cook emerged early in human evolution, before our ancestors split from chimps.
And rather than learning to control fire to provide a source of light and heat, the driving force may have been the desire to cook.
Rosati said: "Why would our ancestors be motivated to control fire? I think cooking might give you a reason."
- Daily Mail