Early human ancestors during the Old Stone Age were pickier about the rocks they used for making tools than previously known, according to research published last week.

The discovery of the rocks used to make tools lends credence to earlier research findings in the same excavation site – Nyayanga in the Homa Peninsula in western Kenya – that the nationwide uniquely Kenyan love for nyama choma (fire or charcoal-roasted meat) is more than 2.9 years.

“Along the shores of Africa’s Lake Victoria in Kenya roughly 2.9 million years ago, early human ancestors used some of the oldest stone tools ever found to butcher hippos and pound plant material, according to new research led by an international team of scientists, including Dr Peter Ditchfield of the Research Laboratory of Archaeology and the History of Art (RLAHA),” findings by School of Archaeology University of Oxford, show.

In a report carried by Associated Press says that not only did these early people make tools, they had a mental picture of where suitable raw materials were located and planned ahead to use them, travelling long distances. By around 2.6 million years ago, early humans had developed a method of pounding rocks together to chip off sharp flakes that could be used as blades for butchering meat.

This allowed them to feast on large animals like hippos that gathered near a freshwater spring at the Nyayanga archaeological site in Kenya.

The earlier study published in February 2023 in the journal Science, says the findings present “what are likely to be the oldest examples of a hugely important stone-age innovation known to scientists as the Oldowan toolkit, as well as the oldest evidence of hominins consuming very large animals.”

It says, “The site featured at least three individual hippos. Two of these incomplete skeletons included bones that showed signs of butchery. The team found a deep cut mark on one hippo’s rib fragment and a series of four short, parallel cuts on the shin bone of another. They also found antelope bones that showed evidence of hominins slicing away flesh with stone flakes or of having been crushed by hammer stones to extract marrow.”

“But hippo skin is really tough” – and not all rocks were suitable for creating blades sharp enough to pierce hippo skin, said co-author Thomas Plummer, a paleoanthropologist at Queens College of the City University of New York.

Co-author Emma Finestone of the Cleveland Museum of Natural History added: “When we think about stone tools, not every rock is equal in terms of the quality of tools.”

At the Nyayanga site, researchers found durable blades made of quartzite, a rock material that they traced to streambeds and other locations around 8 miles (13 kilometres) away. The new research appears in the journal Science Advances.

“This suggests they’ve got a mental map of where different resources are distributed across the landscape,” said co-author Rick Potts of the Smithsonian’s Human Origins Programme.

Previously, researchers had assumed the stones may have been found within just a mile or so of the freshwater spring site.

The new study shows that “these early humans were thinking ahead. This is probably the earliest time we have in the archaeological record an indication of that behaviour,” Eric Delson, a paleoanthropologist at the American Museum of Natural History, who was not involved in the research, said.

The University of Oxford research findings say oldest previously known example of early human ancestors transporting raw materials for tool-making was about 600,000 years later than the Nyayanga site. Researchers said it’s unclear who these early toolmakers were – whether members of the Homo genus or a related but extinct branch of the family tree, such as Paranthropus.

Homo sapiens did not arise until much later, around 300,000 years ago. But the knack for seeking out the best raw materials to make simple technology dates back nearly three million years.

“We today are a species that’s still technology-dependent – using tools to spread around the world and adapt to different environments,” Finestone said in a report cited by Associated Press.

According to University of Oxford researchers, “Using a combination of dating techniques, including the rate of decay of radioactive elements, reversals of Earth’s magnetic field and the presence of certain fossil animals whose timing in the fossil record is well established, the research team was able to date the items recovered from Nyayanga to between 2.58 and 3 million years old.”

It adds that excavations at the site, “named Nyayanga and located on the Homa Peninsula in western Kenya, also produced a pair of massive molars belonging to the human species’ close evolutionary relative Paranthropus. The teeth are the oldest fossilised Paranthropus remains yet found and their presence at a site loaded with stone tools raises intriguing questions about which human ancestor made those tools, said Rick Potts, senior author of the study and the National Museum of Natural History’s Peter Buck Chair of Human Origins.”

“The discovery of teeth from the muscular-jawed Paranthropus alongside these stone tools,” it says further, “begs the question of whether it might have been that lineage rather than the Homo genus that was the architect of the earliest Oldowan stone tools, or perhaps even that multiple lineages were making these tools at roughly the same time.”

• A Tell Media report