OUR earliest ancestors gave up hunting-gathering and took to a settled life up to 400,000 years earlier than previously thought, according to controversial research.
The accepted time scale of humans' evolution is being challenged by an archeologist who claims to have found evidence that Homo erectus - mankind's early ancestor, who migrated from Africa to Asia and Europe - began living in settled communities long before the accepted time of 10,000 years ago.
The point at which settlement took place is the first critical stage in humanity's cultural development.
Helmut Ziegert, of the Institute of Archeology at Hamburg University, said evidence could be found at excavated sites in north and east Africa, in the remains of stone huts and tools created by upright man for fishing and butchery.
Professor Ziegert claimed the thousands of blades, scrapers, hand axes and other tools found at sites such as Budrinna, on the shore of an extinct lake in southwest Libya, and at Melka Konture, along the River Awash in Ethiopia, provided evidence of organised societies.
He believes such sites show small communities of 40 or 50 people, with abundant water resources to exploit for constant harvests.
The implications for our knowledge of human evolution - and of our intellectual and social beginnings - were profound and a "staggering shift", he said.
Professor Ziegert used potassium argon isotopic dating, stratigraphy and tool typology to compile his evidence. He will publish his findings this month in Minerva, the archeology journal.
The news divided scholarly opinion. "This research is nothing less than a quantum leap in our understanding of Man's intellectual and social history," said Sean Kingsley, an archeologist and the managing editor of Minerva.
"For archeology, it's as radical as finding life on Mars.
"As a veteran of over 81 archeological surveys and excavations ... Ziegert is nothing if not scientifically cautious, which makes the current revelation all the more exciting."
Others were far from convinced.
Paul Bahn, an archeologist who specialises in the paleolithic period, believes that Homo erectus was quite advanced and capable of building durable structures, occasionally coming together in large groups, but he remains to be convinced about settlements.
"Homo erectus could have been there for a few days," he said. "He wouldn't have carried the tools around. Inevitably, they accumulate. If hunter-gatherers found no cave or rock shelter, it makes sense that they might have built a shelter for a few days ... The fact they're made out of stone doesn't mean they were permanent settlements."
Homo erectus lived from about 1.6 million to 200,000 years ago, ranging widely from Africa and Asia to parts of Europe. Most of the anatomical differences between Homo erectus and Homo sapiens relate to the skull and teeth, with the former having a jutting browridge, a wide nose and large teeth.
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