Evidence from an ancient Chinese cave has cast doubt on prevailing theories about the taming of fire by human ancestors, suggesting that the epochal achievement occurred much later than scientists have long believed. The findings, if confirmed, could rewrite 60 years of anthropology textbooks and reshape the modern view of Homo erectus, the presumed ancestor of today's humans who was believed to have used fire to sustain migration into the colder regions of Europe and Asia.Zhoukoudian cave, near Beijing, is widely considered to be the site of the world's oldest known campfire, based on charred animal bones, antlers and other artifacts from an apparent H. erectus settlement dating back nearly 500,000 years. But a new, more sophisticated analysis of cave soils turned up no traces of wood ash or other telltale signs that fire was ever used there, an international team of five researchers reports in today's issue of the journal Science.
"In a sense, we spoil the story," lead author Steve Weiner of the Weizmann Institute of Science in Rehovot, Israel, tells the journal. Mastery of fire was the critical achievement that enabled early hominids to vanquish cold and darkness and expand their range into temperate and even glacial lands of the north. With the Zhoukoudian site now in question, the consensus date for the first purposeful use of fire moves forward by at least 100,000 years. Moreover, Weiner and his colleagues suggest that the famous Zhoukoudian cave was never used as a dwelling -- a startling contradiction to what generations of anthropologists have been taught since the site first was discovered 70 years ago.
"In U.S. textbooks, this was the cave home of Homo erectus," said Rick Potts, an anthropologist at Washington's National Museum of Natural History who has visited the site. "Now it turns out it may not have even been a home."
Early human ancestors already had moved into parts of Northern Europe by 300,000 years ago, the approximate date of a encampment near Vertesszollos, Hungary, where archaeologists found charred bones arranged in a radial pattern, suggesting a campfire. That site is between 200,000 and 400,000 years old and would become the best confirmed site for the earliest use of fire. The site is believed to have been occupied by either Homo heidelbergensis or Neanderthals, both of which emerged after H. erectus. Other, more controversial claims have placed the "discovery" of fire as far back as 1.8 million years ago.
Weiner and his colleagues used a variety of instruments to study sediments and other materials from the Chinese cave in what was described as the first systematic investigation of Zhoukoudian since its original excavation in the 1920s and '30s. The earlier digs uncovered a treasure-trove of artifacts and fossilized bones, including some of best-preserved remains of an H. erectus specimen ever found.
"Peking Man," as the fossils were dubbed, disappeared amid confusion during the Japanese invasion of China. But the blackened and tool-scarred animal bones continued to be cited as proof of the fire-making ability of H. erectus, a creature who appeared similar to modern humans in many ways but had a thicker skull, a prominent eyebrow ridge and a smaller brain.
The new analysis confirmed that some of the animal bones in the cave had indeed been burned. But finding no ash or ash remnants, the researchers concluded there is "no direct evidence for in situ fire" in the cave. The vivid red and yellow clays, once interpreted as evidence that the cave was the site of a hearth used for heating or baking, actually were fine sediments deposited by a shallow pond that once covered the cave floor, the researchers concluded.
The mysterious charred bones and other artifacts were "only suggestive" of burning by humans but in fact were probably "somehow burned by natural forces" and possibly were washed into the cave by rainwater or were carried in, Weiner writes. Other scientists are more cautious in interpreting the results. The international team was not able to sample material from all parts of the cave, some scientists point out. And the lack of a hearth in Zhoukoudian doesn't rule out the possibility that fires were in use elsewhere.
Potts notes that the animal bones from Zhoukoudian show signs of a prolonged, intense burn more typical of a hearth than a wildfire. "It is still possible that early humans burned them," he said. "But the absence of a hearth is the absence of a smoking gun."
(Source: The Washington Post / by Joby Warrick - July 10 1998)
