In a 400,000-year-old hearth, hints of humans taming fire earlier than thought

“This is a 400,000-year-old site where we have the earliest evidence of fires, not just in Britain or Europe, but anywhere else in the world,” said Nick Ashton, one of the study’s authors and a curator at the British Museum. Ashton added that this pushes back the first solid evidence of fire by human ancestors by about 350,000 years.

Researchers aren’t sure why these human ancestors used fire — perhaps to roast game, carve tools, or share stories by firelight.

When exactly human ancestors evolved the ability to use fire is a key question that could help unravel some mysteries of human evolution and behavior.

One theory is that the ability to make fire led to an increase in the brain size of human ancestors during evolution, because cooking increases calorie intake by making it easier to digest. Another idea is that controlling fire could also have helped create a gathering space at night, which could have increased human sociality and caused cognitive evolution.

“We know that during this period brain size was increasing to its current levels,” said Chris Stringer, head of human evolution research at the Natural History Museum in London and another author of the Nature study. “Our brains are energy expensive. They use about 20 percent of our body’s energy. So having the use of fire, having the ability to make fire, is going to help release nutrition from food, which will help fuel that brain, keep it functioning. And in effect, you know, will allow the evolution of a bigger brain.”

Stringer said this discovery does not represent the beginning of humans’ ability to make fire, but simply the first example that researchers have confidence in. There are other earlier suggestions that human ancestors used fire in present-day South Africa, Israel, and Kenya, but these examples are subject to debate and interpretation.

Archaeologically, it is difficult to unravel what was a forest fire or whether humans started the fire they used.

“The question is, are they collecting it from natural sources or are they just transporting it and preserving it? Or are they making it up? On the surface, it’s a very compelling case that groups knew how to make fire,” said Dennis Sandgathe, a lecturer in the archeology department at Simon Fraser University in Canada, who was not involved in the research.

In this new Nature study, researchers highlight the presence of sediments containing fire residue, the presence of stone tools like fire-cracked flint axes, and two small fragments of iron pyrite that, according to geological analysis, are extremely rare and were likely brought to the site by humans to make fire.

Other outside researchers were less convinced.

In an email, Wil Roebroeks, professor emeritus of Paleolithic archeology at Leiden University in the Netherlands, wrote that much of the evidence here is “circumstantial.”

Roebrokes noted that more recent Neanderthal sites, dated to around 50,000 years ago, featured flint tools that showed signs of wear indicating they had been struck by pyrite to produce sparks – a “smoking weapon” of human fire production. But that is not the case here.

“The authors have done an excellent job in their analysis of the Barnham data, but they appear to be stretching the evidence by claiming that this constitutes the ‘first evidence of fire,'” Roebroeks wrote.

For human ancestors, fire would become essential for staying warm, getting food, warding off predators, and melting resin into glue, among other uses.

But Sandgathe said it was important to realize that the development of firemaking was not a linear process, but a dispersed process that had fits and starts. There is evidence that groups of human ancestors learned to make fire and then lost the ability or stopped using it for cultural reasons.

“We have to be careful not to take a single example of something … and just project it as an indication that from this point on, everyone is lighting fires,” Sandgathe said, adding that he has reviewed studies of nearly 100 modern hunter-gatherer groups whose lifestyles have been documented in detail by observers. Some groups did not have the ability to make fire.

“The best guess is that fire-making was discovered by several groups in different regions over time, then lost, rediscovered and lost. I’m sure it’s a very complicated story.”