Early humans likely used naturally sharp rocks before making their own tools, a new hypothesis suggests, potentially pushing the origin of stone technology back millions of years.
The development of sharp stone tools over three million years ago enabled early humans to more effectively access both animal and plant food sources. This advancement played a crucial role in the growth of the human brain and set humanity on a technological path that continues today. But how did the process of making these tools, known as “knapping,” begin?
A new hypothesis about the origins of stone tool technology has been proposed by researchers from the Cleveland Museum of Natural History. Dr. Emma Finestone, Associate Curator and the Robert J. and Linnet E. Fritz Endowed Chair of Human Origins, along with research associates Dr. Michelle R. Bebber and Dr. Metin I. Eren, who are also professors at Kent State University, led a team of 24 scientists to publish their findings in the journal Archaeometry.
Rethinking the “Eureka!” Moment
“I don’t think it was a ‘Eureka!’ moment whereby hominins first made a sharp stone flake by intention or by accident and then went to look for something to cut,” says Eren. “There is no reason to produce sharp stone tools unless the need to cut is already in place.”
The new hypothesis proposes that for a substantial amount of time before early humans made their own stone tools they first used and relied on naturally sharp rocks produced via natural geological processes like rocks being knocked together in a stream bed or biological processes like animal trampling of rocks. However, previous research suggested naturally sharp rocks that could have been used as cutting tools – called ‘naturaliths’ – are rare in nature.
Not so, says the new research. Through fieldwork around the world and an extensive survey of scientific literature, Finestone, Bebber, Eren, and their colleagues show that sharp rocks are endlessly produced in a wide range of settings and thus may occur on the landscape in far greater numbers than archaeologists currently understand or acknowledge.
“In some cases, sharp rocks are produced by Mother Nature in the hundreds, thousands, or more” says Bebber who observed one such locality during her fieldwork in Oman. “It is quite astonishing… natural knives were likely readily available to our hominin ancestors.”
Early Access to Natural Tools
And Finestone’s field research in Kenya shows that early hominin food processing sites often occur near naturally occurring sources of stone. “A hominin could have picked up and used a naturally sharp rock to process a carcass or plant material that might have been difficult to access using just their hands and teeth,” says Finestone.
Only after using naturally sharp rocks to cut would there have been selective pressure for early humans to start knapping their own stone tools at will. For example, one potential motivation for knapping would be to solve the problem of limited supply and how to acquire sharp stone flakes in contexts where naturaliths were not present. Or perhaps knapping was a way to improve upon mother nature’s invention by producing stone flakes with desired characteristics, rather than spend time and energy searching for naturaliths that possessed them.
“This is the most parsimonious hypothesis for the origin of hominin stone technology to date,” says Eren. “But parsimony is not necessarily correct – archaeologists now need to test our hypothesis and search for naturalith use by hominins between 3 and 6 million years ago. It is an exciting prospect… if hominins are using naturally sharp rocks as knives, then the archaeological record is going to get a whole lot older.”
Reference: “What can lithics tell us about hominin technology’s ‘primordial soup’? An origin of stone knapping via the emulation of Mother Nature” by Metin I. Eren, Stephen J. Lycett, Michelle R. Bebber, Alastair Key, Briggs Buchanan, Emma Finestone, Joseph Benson, Rebecca Biermann Gürbüz, Adela Cebeiro, Roman Garba, Anne Grunow, C. Owen Lovejoy, Danielle MacDonald, Erica Maletic, G. Logan Miller, Joseph D. Ortiz, Jonathan Paige, Justin Pargeter, Tomos Proffitt, Mary Ann Raghanti, Teal Riley, Jeffrey I. Rose, David M. Singer and Robert S. Walker, 15 March 2025, Archaeometry.
DOI: 10.1111/arcm.13075
The study was funded by Kent State University.
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14 Comments
“However, previous research suggested naturally sharp rocks that could have been used as cutting tools – called ‘naturaliths’ – are rare in nature.”
While ‘naturaliths’ may exist, a stream bed is not a good place to find them. They are more likely to be found at the base of cliffs where a fall would cause them to shatter. The observation of it happening would have certainly led to primitive people trying to mimic the process by smashing two cobbles together.
Why is it so hard to believe that ancient man was not stupid? No, they did not make Electeic Cars. But they did survive and thrive. I fear that our “science” of early man is too influenced by traditions that have no real proof other than someone wants to believe that they are at the top of the evolutionary ladder. For far too long these “men” have controlled who says what, who goes where, who gets what grant, who … The very best of us can only really guess at what was. Yes it is interesting. But unless it cures cancer, it is nothing more than just interesting. Knowing where we came from does not make peace in the Ukraine. Understanding how early man skinned dear hides does not help my grandmother with her dementia. Let’s put our best minds and great resources to work on those things, before another COVID break out occures and extinguishes the light of mankind.
Yes yes yes !! Thanks Dr. Thomas!
This is where tax dollars are being spent. Neanderthals are named from the Neander Valley in Germany. The neanderthals, along with many other tribes, had inbreeding thus causing genetic problems. Everybody, excluding a lot of African tribes, have neanderthal DNA especially east Asians and people from the Middle East that travelled to the Americas and are called native Americans. Regular people, not something that evolved. I mean this can get real stupid, like it was theorized that the pyramids were built by aliens. We are just going in circles. Professing themselves wise they became fools.
Just to make a correction about Native Americans. Their ancestors would have travelled from east Asia and are not from the Middle East. Their closest relatives would have come from Siberia.
And to add even more correction, the inbreeding and crossbreeding percentage of Neanderthal (and Denisovan) genome matareial *is* evolution, as are regular people.
And to add even more correction, the in-breeding and cross-breeding percentage of Neanderthal (and Denisovan) genome material *is* evolution, as are regular people.
Your conspiracy theory lacks evidence. And what you say on science, or society in general, is manifestly wrong since e.g. evolutionary science is used in medicine to e.g. extrapolate virus evolution to improve our vaccines
To Joel Calandra – the solutions you asked for require understanding that comes from the outside of the practical problem you want addressed. For example to fight cancer you need to understand we are made of cells, how DNA regulates their growth, what causes them fail to control the growth, and many other facts of biology, you would never think about without non-cancer biology. Using money to address problems would be extremely inefficient (slow) and costly. Do you really think that a few million scientists are stupid and you know better?
Of course they did! It’s just silly to think that someone who found a sharp stone wouldn’t have used it to help them live.
Wow, the same hypothesis we reached as high school students hunting arrowheads in the 1970s. Good work Kent State…
I put forth the same theory in 1968 when I was 10. I was trying to knapp some rocks down in Anza-Borrego and doing a bad job of it, when I tipped backwards and cut my arm on a really sharp natural rock. Thats when it hit me. Early hominids used whatever they could find that fit the bill. It was only later that they saw how rocks fractured that they began to smash rocks on the ground to get a useful tool, and much later, knapping their own.
одно другому совсем не мешает в условиях скудной пищи любые трубчатые кости животных неплохое дополнение, разбивая целыми камнями могли получать и осколки. Мне думается что человеками они стали когда начали прикидывать куда осколки применить, бросать все и бежать за новым камнем , человеку несвойственно. Хороший каменный топор получается если рукоятку расщепив примотать свежей кожурой от кустарников, и слегка нагреть на огне, можно дерево срубить не расшатается, кожи и веревки не держат, наконечники для стрел лучше костяные. были.
We share percussion stone tool use with chimps and bonobos, and that has AFAIK been considered the expected and found start.
They supposed hypothesis is too vaguely outlined to analyze.