Our prehistoric human ancestors relied on deliberately modified and sharpened stone tools as early as 3.3 million years ago. The selection of rock type depended on how easily the material could be flaked to the desired shape and form.
The resulting product proved invaluable for everyday tasks. Sharp-edged rock fragments were manufactured to suit various needs, including hunting and food processing.
The Stone Age period lasted from about 3.3 million years ago until the emergence of metalworking technologies. Throughout this time, diverse tool-making traditions flourished. Among them is the Oldowan tradition, one of the earliest technological systems created by our early ancestors. The tools are not shaped to have “fancy looks”. Still, they represent a huge step in human evolution. They show that our ancestors had begun modifying nature intentionally, creating tools with a purpose rather than just relying on naturally sharp stones.
Evidence from Homa Peninsula on the Kenyan side of Lake Victoria and Koobi Fora, Kenya’s Lake Turkana, places the origins of the Oldowan between 2.6 million and 2.9 million years ago at these sites. For nearly a million years, this technology stayed within Africa, becoming a key part of how early humans survived.
Over time, the knowledge of how to produce and use stone tools spread. By about 2 million years ago, Oldowan toolmaking had spread across north Africa and southern Africa. It eventually extended into Europe and Asia as our ancestors expanded their geographic range.
Although these tools appear basic, their manufacture required skill, planning, and a thorough understanding of stone fracture mechanics. Hominins made sharp flakes by striking rocks against other rocks to break them. The resulting sharp edges could then be used for butchering animals, processing plants, and breaking bones for marrow.
Until recently, the oldest known evidence of tool use found on the eastern shore of Lake Turkana, in Kenya, was dated to around 2 million years ago. The region is one of the world’s richest areas for early human fossils and archaeological remains, yet it lacked a secure, long-term sequence of early Oldowan occupation.
That picture has now changed dramatically.
We are researchers who study ancient life and landscapes, and we have now documented some of the oldest evidence yet of Oldowan tools. They are 2.75 million years old and come from East Turkana, at a site called Namorotukunan in Kenya. They are nearly 700,000 years older than other Oldowan sites from this part of Lake Turkana (and older than Oldowan tools from the Afar, Ethiopia, by about 150,000 years).
At this site, there were three distinct archaeological horizons (layers of sediment that record separate events of tool making activities), spanning 300,000 years. But throughout this long period, during which the climate and landscape changed, our hominin ancestors continued to make and use the same kind of tools. Our findings tell us something about their ability to make choices that enabled them to adapt, survive and evolve.
A landscape in constant transition
Today, the Turkana Basin experiences hot, arid to semi-arid conditions with daily average temperature of around 35°C. The vegetation cover is heterogeneous and includes bushland, shrubland and sparse grasslands with distribution influenced by seasonal drainage systems and groundwater.
Between 3 million and 2 million years ago, the region experienced major landscape transformations due to strong climatic fluctuations. Evidence from Namorotukunan shows that it shifted from a lakeshore setting to a dry semidesert, then to open savannah, and eventually became submerged again as the lake expanded. Along its banks, early human ancestors gathered stones, striking them with precision to make stone fragments, sharp enough to use as implements that allowed them to access different types of foods.
Before approximately 2.8 million years ago, the Turkana Basin had lush floodplains with abundant standing water, palm trees, and wetland vegetation. Approximately 2.75 million years ago, the region began to dry out as grasslands expanded and subsequently replaced forests. Despite this increasing aridity, early toolmakers remained in the landscape. Our ancestors took advantage of river gravels that provided good-quality stone (especially chalcedony) for manufacturing sharp-edged stone tools.
By approximately 2.58 million years ago, the climate had become even drier and more variable. Nevertheless, early humans continued to produce the same style of tools, demonstrating technological persistence despite fluctuating environmental conditions.
At about 2.44 million years ago, semi-arid conditions persisted, followed by flooding of the lake, eventually submerging the region again. However, as landscapes changed once again, toolmakers continued to return to this same region, producing Oldowan tools that remained unchanged in form.
This persistence suggests that these early humans had developed a successful survival strategy that worked across a wide range of ecological settings.
Selecting and using the best rocks
The stone tools at Namorotukunan were not made from just any rock. Nearby outcrops offered a variety of raw materials, but early humans selected the most suitable types of rock for their needs. They chose high-quality stones that break easily to produce sharper edges.
This kind of selectivity suggests an understanding of how different rocks behaved during breakage and reflects the cognitive capabilities of the early humans who made and used these stone tools.
Understanding the functional importance of these stone tools from this site is crucial to evaluating their evolutionary significance.
One clue comes from a fossilised animal bone found at the site, bearing cut marks made by sharp-edged stone tools. These marks reveal that the toolmakers were cutting animal tissues and likely accessing meat or marrow from animal carcasses.
Such evidence supports previous studies that early humans were beginning to rely more heavily on meat and marrow, a dietary shift that played a major role in human evolution. Eating meat may have provided critical calories and nutrients that fuelled the growth of larger brains. The tools might also have been used to dig for underground plant parts or process other foods.
This suggests that early hominins were experimenting with various ways of surviving in the ever-changing environment around them.
Adapting to instability
The technological continuity at the site shows that Oldowan toolmaking was more than a simple craft. It was a dependable survival strategy, one that likely became essential during dry periods, when plant foods were scarce and it was vital to eat meat and marrow.
The ability of the early toolmakers to select high-quality stone, produce sharp flakes, and return to familiar raw-material sources suggests a deep understanding of their landscapes. It allowed early hominins to survive ecological uncertainty over hundreds of generations.
This research would not have been possible without the continued support of the Daasanach community of Ileret, who welcome researchers onto their land each year, and the National Museums of Kenya, whose leadership and collaboration underpin archaeological and geological work across the Turkana Basin.
Niguss Gitaw Baraki receives funding from the Leakey Foundation and the U.S. National Science Foundation.
Dan V. Palcu Rolier’s work was supported by NWO Veni grant 212.136, FAPESP grants 2018/20733-6 and 2024/21420-2, and the PNRR C9-I8 grant 760115/23.05.2023.
David R. Braun receives funding from the U.S. National Science Foundation, The Leakey Foundation, and The PAST Foundation.
Emmanuel K. Ndiema and Rahab N. Kinyanjui do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
