They dined on raw meat, huddled in the cold, and slept fitfully in the dark, fearing the approach of large predators. But eventually, early humans reached a crucial turning point: They learned to make fire. Kindling and controlling a small blaze, they cooked their dinners, socialized around warm hearths, and frightened off large, menacing carnivores. Now, a new study suggests that humankind tamed the flame at least 200,000 years earlier than previously thought.

"I think this research establishes as well as possible that by 1 million years ago, early humans were able to control fire," says one of the paper's authors, archaeologist Michael Chazan of the University of Toronto in Canada.

The new evidence comes from a site known as Wonderwerk Cave in South Africa. Back in the 1980s, a now-retired South African archaeologist, Peter Beaumont, found what appeared to be wood ash and charcoal in a layer of sediment dated to 1.7 million years ago. But early claims for fire are often controversial because it is difficult to distinguish between natural fires and those set by humans. The most widely accepted previous claim came from the site of Gesher Benot Ya'aqov in Israel, where archaeologists found traces of what appeared to be fire dating to 790,000 ago.

Other researchers challenged Beaumont's finding. The ash and burnt bits, critics suggested, could have blown into the cave from a forest fire or resulted from the spontaneous combustion of bat guano--an event that is rare but has been documented elsewhere. So when Chazan and his team began working at Wonderwerk Cave, they took a new look at the evidence.