Scientists have found stone tools dating back 3.3 million years in the desert of northwestern Kenya.
The find pushes the known date of such tools back by 700,000 years. They may also challenge the idea that direct human ancestors were the first to use tools.
The stone tools mark “a new beginning to the known archaeological record,” say the authors of a paper about the discovery in the journal Nature.
“The whole site’s surprising, it just rewrites the book on a lot of things that we thought were true,” said geologist Chris Lepre of the Lamont-Doherty Earth Observatory and Rutgers University.
The researchers think the tools could have been used for breaking open nuts or tubers, bashing open dead logs to get at insects inside, or maybe something not yet thought of.
But they don’t know who made these oldest of tools.
But earlier finds suggest a possible answer. The skull of a 3.3-million-year-old hominin, Kenyanthropus platytops, was found in 1999 about one kilometre from the tool site. A K. platyops tooth and a bone from a skull were discovered a few hundred metres away and an as-yet unidentified tooth has been found about 100 metres away.
The precise family tree of modern humans is still being debated.
There is some evidence of more primitive tool use going back before the latest find. In 2009, researchers at Dikika, Ethiopia, dug up 3.39 million-year-old animal bones marked with slashes and other cut marks, evidence that someone used stones to trim flesh from bone and perhaps crush bones to get at the marrow inside.
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