Israeli scientists have discovered evidence of the earliest known use of fire by humans. The remains of burned seeds, wood, and flint near an Israeli lake shore appear to be leftovers from campfires that blazed almost 800,000 years ago.

Sitting around a crackling campfire is one of the oldest human activities. But no one knows how old.

The earliest accepted date for human control of fire has been 250,000 years ago based on foolproof evidence of well-preserved hearths in cave sites. But researchers from Hebrew and Bar-Ilan Universities in Israel have found signs of controlled burning more than three times that old, from about 790,000 years ago.

"What we actually found is the earliest evidence for the use of fire," explained Hebrew University archaeologist Naama Goren-Inbar. She and her colleagues report in the journal Science that the evidence they found consists of tiny pieces of burned flint and the charcoal remains of six types of wood, including olive, barley, and grape well preserved by water-logged layers of soil near an Israeli lake.

"The combination of the two types of evidence is very important because this was rarely ever demonstrated elsewhere," she added. "We were able to demonstrate that this burning is not a natural fire, but this is [caused by] human involvement."

Ms. Goren-Inbar's Hebrew University co-researcher, Nira Alperson, says the evidence that the fire was not natural is strong. They found the burned flint in clusters, suggesting locations where people had regular fires.

"If a natural fire would have occurred, we would expect the distribution of burnt items to be random, to be spread all over the site. We would also expect to have a much larger frequency of burned items," she said.

The Israeli researchers say the fire users were not modern humans, but possibly any of three different species that lived before us.

University of Colorado archaeologist Paola Villa says if their claim is substantiated, it might help explain how early humans were able to migrate and adapt to cold climates.

"This paper is important because it is the first evidence of fire at a very early time outside Africa more or less at the time when humans were expanding into Europe," she explained.

Ms. Villa says the burden is now on archaeologists to find examples of controlled fire in Europe around this time. She points out that there is evidence of early human settlements in England about 500,000 years ago, but no signs of any manmade fires there.

"Until now, European archaeologists have not concentrated enough on this topic, so it is about time they start looking harder for this kind of evidence, because if humans did not have fire and yet they colonized these fairly cold countries, then it is a surprise and it means that humans were more adaptable than we thought they were," she said.

If human use of fire is at least 790,000-years-old, might it be even older? No one can say for certain without the scientific evidence.

But Nira Alperson of Hebrew University says it is important to determine when humans first controlled fire because it helped provide an enormous advantage over other species. In her view, use of fire is one thing that separates us from animals, perhaps even more so than language.

"If we look at language, we can see species that have certain degrees of communication. Fire is one thing that man was able to control and domesticate," she said.