Homo erectus - The world's first cook?

New research suggests that early hominids of the species Homo erectus, which lived between 1.8 and 1.5 million years ago, may have cooked and processed their food in the same way that we do.

Humans have much smaller molar teeth than other primates of comparable body size, and also spend much less time eating. Scientists at Harvard University calculated that, based on their body mass and calorie requirements, if humans behaved like all other primates we would expect them to spend 48% of their time feeding. In reality for the average human this is just under 5%.

Primatologist Zarin Machanda and her colleagues suggest these differences between humans and other primates exist because humans cook and process their food before eating it. 

"When you cook food it becomes softer, you can chew it more easily, and you can actually get more calories out of it than if you eat it raw," said Dr Machanda, "Cooking is an important human behaviour....what we did in this paper is try to look at when, and how quickly, this trait evolved."

The team conducted a comparative analysis of body mass, molar size, skull and jaw characteristics along with genetic data for modern humans, primates and several extinct human ancestor species.

In addition to Homo sapiens, two other hominid species were found to have small molars that could not be explained solely by the patterns of body mass or jaw evolution alone: Homo neanderthalis and the more ancient Homo erectus. This indicates that early hominids underwent a dramatic dietary shift which the researchers propose could have been driven by the ability to cook.

Cooking may have helped our ancestors survive and enabled the hominid lineage to persist throughout evolutionary history.  "Energy is a currency that animals work with, so the more calories you have the more energy you have and if you can increase energy that could give you an evolutionary advantage," said Dr Machanda. "We think that's why every modern human culture cooks its food."

The research was published this week in the journal PNAS. 

Click to hear the full interview with Dr. Zarin Machanda