Evidence from Kenya shows that key stone tools in the development of early humans were made by transporting materials over long distances 600,000 years earlier than previously thought.
An array of stone tools known collectively as the Oldowan toolkit were used by human ancestors to crush plant material and butcher large carcasses like those of hippopotamuses.
An Oldowan flake that was found alongside a hippopotamus shoulder bone at a hippo butchery site excavated in Nyayanga. Credit: T.W. Plummer, Homa Peninsula Paleoanthropology Project.
Oldowan tools are the oldest evidence of stone tool industry and cultural behaviour in human history. The earliest are at least 2.6 million years old but could have been made up to 3 million years ago (mya). They came relatively soon after the very first stone tools ever made 3.3 mya.
Such was their success that they were the primary tools used by human ancestors for more than a million years, made by early hominin species Homo habilis (the ‘Handy Man’) and possibly others including Homo rudolfensis, Australopithecus garhi and Paranthropus boisei.
Scientists theorised these early human relatives relied on local resources until about 2 mya.
Geochemical analysis of 401 Oldowan tools from Kenya, published in the journal Science Advances, reveals these ancient hominins sourced higher quality stones from up to 13km away as early as 2.6 mya.
Oldowan tools made from a variety of raw materials that were sourced from over 10km away from the Nyayanga. Credit: E.M Finestone, J.S. Oliver, Homa Peninsula Paleoanthropology Project.
“People often focus on the tools themselves, but the real innovation of the Oldowan may actually be the transport of resources from one place to another,” says senior author Rick Potts, from the Smithsonian’s National Museum of Natural History in the US. “The knowledge and intent to bring stone material to rich food sources was apparently an integral part of toolmaking behaviour at the outset of the Oldowan.”
The tools were found at the Nyayanga site. Local rocks are relatively soft, meaning tools produced from them would quickly dull or shatter. So, it seems the ancient hominins strategically brought rocks long distances.
“It’s surprising because the Nyayanga assemblage is early in the Oldowan and we previously thought that longer transport distances may have been related to changes that happened in our more recent evolutionary history,” says the aptly named study lead Emma Finestone from the Cleveland Museum of Natural History, also in the US.
Nyayanga excavation site in July 2025. Tan and reddish-brown sediments are more than 2.6-million-year-old deposits where fossils and Oldowan tools are found. Credit: T.W. Plummer, Homa Peninsula Paleoanthropology Project.
The identity of the toolmakers remains a mystery. Homo habilis first emerges in the fossil record about 2.4 mya – at least 200,000 years after the tools found at the Nyayanga site were produced.
“Unless you find a hominin fossil actually holding a tool, you won’t be able to say definitively which species are making which stone tool assemblages,” Finestone says. “But I think that the research at Nyayanga suggests that there is a greater diversity of hominins making early stone tools than previously thought.”
“Humans have always relied on tools to solve adaptive challenges,” she adds. “By understanding how this relationship began, we can better see our connection to it today – especially as we face new challenges in a world shaped by technology.”