A team of scientists led by Dr Sonia Harmand of Stony Brook University has unearthed the earliest tools ever found – dated at 3.3 million years old.
A stone tool during the process of excavation at the Lomekwi 3 site in Kenya. Image credit: MPK-WTAP.
The artifacts were found at the archaeological site Lomekwi 3 on the western shore of Lake Turkana in northern Kenya.
They show that at least one group of ancient hominin started intentionally ‘knapping’ stones to make sharp tools long before previously thought.
“These tools shed light on an unexpected and previously unknown period of hominin behavior, and can tell us a lot about cognitive development in our ancestors that we can’t understand from fossils alone. Our finding disproves the long-standing assumption that Homo habilis was the first tool maker,” said Dr Harmand, lead author of a paper published in Nature.
In the 1930s, scientists Louis and Mary Leakey unearthed early stone artifacts at Olduvai Gorge in Tanzania and named them the Oldowan tool culture.
In the 1960s they found hominin fossils – in association with those tools – and assigned them to a new species, Homo habilis (handy man).
“Conventional wisdom in human evolutionary studies since has supposed that the origins of knapping stone tools was linked to the emergence of the genus Homo, and this technological development was tied to climate change and the spread of savannah grasslands,” said co-author Dr Jason Lewis of Stony Brook University. “The premise was that our lineage alone took the cognitive leap of hitting stones together to strike off sharp flakes, and that this was the foundation of our evolutionary success.”
The newly-discovered tools are much larger than later Oldowan tools. “And we can see from the scars left on them when they were being made that the techniques used were more rudimentary, requiring holding the stone in two hands or resting the stone on an anvil when hitting it with a hammerstone,” Dr Harmand said.
“Some of the gestures involved are reminiscent of those used by chimpanzees when they use stones to break open nuts.”
The study of the Lomekwi 3 artifacts suggest they could represent a transitional technological stage – a missing link – between the pounding-oriented stone tool use of a more ancestral hominin and the flaking-oriented knapping of later, Oldowan toolmakers.
“I have no doubt that these aren’t the very first tools that hominins made,” Dr Harmand said.
“They show that the knappers already had an understanding of how stones can be intentionally broken, beyond what the first hominin who accidentally hit two stones together and produced a sharp flake would have had. I think there are older, even more primitive artifacts out there.”
“The Lomekwi 3 stone tools join cut-mark evidence from Dikika in pushing the origins of stone cutting tools back to almost 3.5 million years ago. This raises new questions about the differences between stone tools made by earlier hominins and those by recent humans. The really interesting scientific question is, What pushed early hominins to make stone tools at that place and at that point in time? What were they doing with the tools?” said Prof John Shea of Stony Brook University, who was not involved in the study.
“The capabilities of our ancestors – and the environmental forces – leading to early stone technology are a great scientific mystery. The modified stones from Lomekwi begin to lift the veil on that mystery, at an earlier time than expected. Researchers have thought there must be some way of flaking stone that preceded the simplest tools known until now. Dr Harmand’s team shows us just what this even simpler altering of rocks looked like before technology became a fundamental part of early human behavior,” said Dr Rick Potts of Smithsonian Institution.
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Harmand, S. et al. 3.3 Million-Year-Old Stone Tools from Lomekwi 3, West Turkana, Kenya. Nature, published online May 21, 2015
