WASHINGTON: Chimpanzees have the cognitive abilities required for cooking, which were believed to be limited to humans, and the primates even choose to hoard raw vegetables if they know they will have the chance to 'cook' them later on, according to a new research.
Scientists found that chimpanzees prefer the taste of cooked food, can defer gratification while waiting for it and choose to hoard raw vegetables if they know they will have the chance to eat cooked vegetables later on.
The transition to cooked food is widely viewed as an important evolutionary milestone because it would have allowed our primitive forebears to expand their diet and extract far more calories, reducing the amount of time required for foraging and chewing.
While various animals have been shown to have a preference for cooked vegetables and meats, which are softer and easier to digest, the intellectual abilities required to make the leap to preparing cooked food had been thought to be limited to humans.
"What's 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," said Felix Warneken, a psychologist at Harvard University and co-author of the study.
In a series of experiments at the Jane Goodall Institute's Tchimpounga Chimpanzee Sanctuary in the Democratic Republic of Congo, wild-born chimpanzees were given the opportunity to prepare food using a 'cooking device'.
This was a plastic lunchbox with a false bottom, which researchers used to "transform" raw sweet potato placed inside by the chimpanzees into a cooked slice of a similar size.
Overall, the apes chose cooked potato nearly 90 per cent of the time when they were given a choice and they were nearly as keen when they had to wait one minute while it was "cooked" by the researcher (who shook the plastic box ten times).
The chimps continued to opt for the cooked option 60 per cent of the time when they had to carry the food some distance in order to place it in the "oven".
Around half the chimps chose to hoard raw potato - setting aside up to 28 slices - when they knew they would be presented with the option of cooking it later on, 'The Guardian' reported.
"Usually chimpanzees just eat what they can get right away and would never give up edible food, so it was remarkable to see that," Warneken said.
The researchers said that if the ability to cook emerged early on in our evolution, this may even have been the motivation for harnessing fire in the first place, possibly after humans had first got a taste for food prepared opportunistically on natural fires.
"The evidence from our cognitive studies suggests that, even before controlling fire, early hominins understood its benefits and could reason about the outcomes of putting food on fire," said Alexandra Rosati, the study's co-author and an evolutionary biologist at Yale University.