March 15, 2011

Neanderthals Controlled Fire 400,000 Years Ago

A new study shows clear evidence that our ancient human ancestors in Europe learned to control fire -- one of the most important milestones on the path to civilization -- some 400,000 years ago.

The findings are another indication that Neanderthals weren't simply dimwitted brutes, as often portrayed, and were in fact able to thrive in Europe's northern latitudes without the use of fire.  The researchers suggested that a highly active lifestyle, along with a diet high in protein, might have helped them survive the cold climates.

The scientists reviewed 141 archaeological sites across Europe, and found convincing evidence of long-term, habitual use of fire by Neanderthals beginning between 300,000 and 400,000 years ago.

Most archeologists believe the use of fire is tied to colonization outside Africa, particularly in Europe where sub-zero temperatures occur, wrote Wil Roebroeks of Leiden University in the Netherlands and Paola Villa of the University of Colorado in a paper about the findings.

However, while there is evidence of early humans living in Europe a million years ago, the researchers found no clear evidence of regular use of fire before 400,000 years ago.

"Until now, many scientists have thought Neanderthals had some fires but did not have continuous use of fire," said Villa.

"We were not expecting to find a record of so many Neanderthal sites exhibiting such good evidence of the sustained use of fire over time."

Neanderthals are believed to have evolved in Europe 400,000 to 500,000 years ago, and went extinct about 30,000 years ago.

They ranged throughout much of Europe and into Central Asia, were stockier than modern humans and even shared the same terrain for a time.  In fact, there is evidence that contemporary humans carry a small amount of Neanderthal DNA.   Modern humans began migrating out of Africa to Europe some 40,000 years ago.

Archaeologists consider the emergence of stone tool manufacturing and the control of fire as the two hallmark events in the technological evolution of early humans.  However, while scientists agree the origins of stone tools date back at least 2.5 million years in Africa, the origin of fire control has been a long and contentious debate.

Villa and Roebroeks created a database of 141 potential fireplace sites in Europe dating from 1.2 million years ago to 35,000 years ago, assigning an index of confidence to each site.  Evidence for the sustained use of fire includes the presence of charcoal, heated stone artifacts, burned bones, heated sediments, hearths and rough dates obtained from heated stone artifacts. Sites with two or more of these characteristics were considered solid evidence that the inhabitants controlled fire.

Roebroeks said the second, perhaps more surprising, major finding was that Neanderthal predecessors pushed into Europe's colder northern latitudes more than 800,000 years ago without the habitual control of fire.

Archaeologists have long believed the control of fire was necessary for migrating early humans as a way to reduce their energy loss during winters, when temperatures dropped to below freezing and resources became more scarce.

"This confirms a suspicion we had that went against the opinions of most scientists, who believed it was impossible for humans to penetrate into cold, temperate regions without fire," Villa said.

Recent evidence from an 800,000-year-old site in England known as Happisburgh indicates hominids -- likely Homo heidelbergenis, the forerunner of Neanderthals -- adapted to cold environments in the region without fire, Roebroeks said.

The simplest explanation is that there was no habitual use of fire by early humans before 400,000 years ago, indicating that fire was not an essential component of the behavior of the first occupants of Europe's northern latitudes, said Roebroeks.

"It is difficult to imagine these people occupying very cold climates without fire, yet this seems to be the case."

While the oldest traces of human presence in Europe date to more than 1 million years ago, the earliest evidence of habitual Neanderthal fire use comes from the Beeches Pit site in England dating to roughly 400,000 years ago, said Villa. The site contained scattered pieces of heated flint, evidence of burned bones at high temperatures, and individual pockets of previously heated sediments.

According to Villa, one of the most spectacular uses of fire by Neanderthals was in the production of a sticky liquid called "pitch", obtained from the bark of birch trees, that was used by Neanderthals to fit wooden shafts on stone tools.

Since the only way to create pitch from the trees is to burn bark peels in the absence of air, archaeologists surmise Neanderthals dug holes in the ground, inserted birch bark peels, lit them and covered the hole tightly with stones to block incoming air.

"This means Neanderthals were not only able to use naturally occurring adhesive gums as part of their daily lives, they were actually able to manufacture their own," Villa said.

"For those who say Neanderthals did not have elevated mental capacities, I think this is good evidence to the contrary."

Many archaeologists believe Neanderthals and other early hominids struck pieces of flint with chunks of iron pyrite to create the sparks that made fire, and may well have conserved and transported fire from site to site.

Some anthropologists have proposed that Neanderthals became extinct because their cognitive abilities were inferior, including a lack of long-term planning, said Villa.

However, the archaeological record shows Neanderthals drove herds of big game animals into dead-end ravines and ambushed them, as evidenced by repeatedly used kill sites -- a sign of long-term planning and coordination among hunters, she said.

The findings were published in Tuesday's edition of Proceedings of the National Academy of Sciences. 


Image Caption: A new study involving the University of Colorado Boulder indicates Neanderthals had achieved continuous control of fire by roughly 400,000 years ago. Credit: JPL/NASA


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