Chimp Chef Wanna-Be's Reveal Origin of Cooking

It doesn't take much coaxing to get a chimp to pull out a pot or pan and cook, finds a new study.

Chimpanzees not only prefer cooked foods versus those that are raw, but they also can cook, and elect to do so, when presented with easy-to-operate devices, new research finds.

The surprising findings, outlined in a study in the journal Proceedings of the Royal Society B, demonstrate that our closest evolutionary relatives have nearly all of the inherent skills necessary to accomplish basic cooking. This, in turn, suggests that the skills were present in the common ancestor of chimps and humans.

But don't expect a chimp-hosted cooking show anytime soon.

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"There are some ethical issues with providing the chimpanzees access to actual fire -- given the danger," co-author Alexandra Rosati of Yale University's Department of Psychology told Discovery News. She explained that the cooking devices used in the study were chosen and presented with chimp safety in mind.

The study, co-authored by Felix Warneken of Harvard University's Department of Psychology, actually consisted of nine different experiments. In the first, chimps were presented with a raw or cooked sweet potato at room temperature, to see which type they preferred. The vast majority went for the cooked potato.

Experiment 2 determined that chimps have patience when waiting for cooked food, while experiments 3 and 4 found that chimpanzees choose to cook their own food when presented with simple cooking devices that they figured out how to operate. Experiment 5 replicated that discovery.

Experiment 6 determined that their rudimentary cooking skills generalize to other foods–in this case, carrots. Experiment 7 found that they selectively can cook edible items (the chimps cooked raw potato slices versus inedible wood chips that they were given).

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The final experiments demonstrated that chimps will transport food in order to cook it, and that they will save their food for future cooking. All of these skills represent fundamental psychological abilities necessary to engage in cooking. The common ancestor of chimps and humans therefore likely possessed these very same skills.

Humans, however, are the only primates known to control fire of their own volition. Our ancestors, perhaps starting with Homo erectus aka "Upright Man," might have begun to cook foods around 2 million years ago, long before our species evolved.

Rosati said, "There is some evidence that Neanderthals may have cooked some food," given that bits of probable fossilized cooked items have been found between Neanderthal teeth.

In terms of what compels any individual to want cooked food in the first place, Rosati said that at least one prior study concluded "that both the taste of the cooked food as well as its softer texture may make it more appealing."

Warneken added that other studies have found "that cooking allows animals to extract more energy from food than when it is raw."

He continued, "Given that brains are an energetically expensive tissue -- and humans have brains that are both relatively and absolutely larger than other primates -- the shift to a cooked diet may have been a critical factor in the evolution of larger brains in the human lineage."

Then there is the question: which came first, a change in the human diet that led to a desire to cook certain foods, or the ability to cook, which might have led to a change in diet?

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The researchers said that the answer remains unknown for now, but it's possible that discovering edible starchy raw tubers, which "are fairly undesirable when raw," prompted our ancestors to cook them.

Primatologist Richard Wrangham of Harvard University's Center for the Environment, told Discovery News, "I am as impressed at the authors' ingenuity in devising these experiments and carrying them out so convincingly as I am at the results."

He added, "I hope that this study continues to encourage archaeologists to find new ways to test the prediction that I favor, which is that hominins (early humans) began using fire around 2 million years ago or earlier, well before the current earliest strong evidence at 1 million years ago."

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