A chance find in the Rift Valley of northwest Kenya sheds new light on the history of our species.
Archaeologists have discovered stone tools created by our ancestors 3.3 million years ago – considerably older than the 2.6 million year old Oldowan stone tools that were previously the oldest stone tools ever found. The discovery at the Lomekwi 3 site near Lake Turkana was led by Sonia Harmand at Stony Brook University in New York and has been reported in the journal Nature.
Until recently it was generally thought that our ancestors only became sufficiently intelligent to make complex stone tools with the emergence of Homo habilus – a name that translates as ‘the handy man’ – who lived in Africa around the same time as Oldowan tools appear in the archaeological record.
The new discovery overturns that idea. The tools were created when ape-like species such as Kenyanthropus platytops and Australopithecus afarensis – of which the fossil Lucy was a member – are known to have roamed this part of Africa.
The newly discovered tools are certainly more primitive than the Oldowan stone tools that appeared 700,000 years later.
But whoever made the Lomekwi tools apparently had more brainpower than today’s chimps. Aside from humans, chimps are the only species known to use stone tools, using one rock to crack open a nut placed on another rock. But chimps do not deliberately crack rocks together to create cutting tools.
Around 1.7 million years ago, Oldowan tools began to be replaced by Acheulean blades, which were created by means of a more sophisticated flaking technique which was further refined over time.
The chances are the Lomekwi 3 tools will not turn out to be the first stone tools our ancestors created. In 2009, researchers at Dikika, Ethiopia, dug up 3.4 million-year-old animal bones bearing cut marks that seem to have been created by somebody using a sharp-edged stone to trim flesh from bone and perhaps crush bones to get at the marrow inside.
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