In southwestern Kenya more than 2.6 million years ago, ancient humans wielded an array of stone tools—known as the Oldowan toolkit—to pound plant material and carve up large prey.

The tools were crafted from special stones collected up to eight miles away, according to new research from a team of scientists at the Smithsonian National Museum of Natural History and Queens College, led by Dr. Emma Finestone, paleoanthropologist, associate  curator of human origins, and the Robert J. and Linnet E. Fritz Endowed Chair of Human Origins at The Cleveland Museum of Natural History (CMNH).

Their findings push back the earliest known evidence of ancient humans transporting resources over long distances by some 600,000 years.

The group’s research focuses on the recently discovered Nyayanga site on Kenya’s Homa Peninsula, a fossil-rich region that juts out into the eastern margins of Lake Victoria. The site provides insights into the complex decision-making abilities of our early ancestors.

"Toolmakers were traveling much longer distances than has been previously documented in that time period," explains CMNH’s Finestone. "They were traveling over 10 kilometers to get high quality stones that are sharper and more durable than the stones that were available locally."

In a new Science Advances study, “Selective use of distant stone resources by the earliest Oldowan toolmakers,” Finestone worked with several colleagues to analyze stone tools uncovered on the Nyayanga site.

Finestone says that while the Nyayanga location offered crucial resources like water and shelter, the local rocks were unsuitable for toolmaking.

"The mountain happens to produce less suitable rocks to use as tools,” she says. “They are softer, they break apart easily if you try to use them for pounding...they'll [go] dull easily if you're using them to cut."

The tools’ limitations helped researchers understand early hominin behavior. "Nyayanga had attractive features in terms of food resources, shade, water, the other basic needs that hominins would have relied on,” Finestone explains. “But because [the site] had low quality stone tools, it provided motivation to [travel] further to acquire tools from other, more distant sources."

The implications of these findings are significant. "This is important because it shows that between 2.6 and 3 million years ago, hominins had a mental map of the landscape that incorporated not just food resources, but also stone resources," Finestone says. "This is part of a uniquely human foraging strategy where we incorporate tools into our food acquisition strategies and our daily lives in a way other animals don't."

The research also raises questions about which of our ancestors were responsible for these tools. Finestone points out that fossils found at the site belonged to Paranthropus, which is a direct offshoot of human lineage.

“They weren't expected to be tool users,” says Finestone, “because the assumption is that it was genus Homo making these tools."

However, Finestone says the sophisticated tools don’t necessarily demonstrate advanced cognitive abilities.

"I don't think traveling for stone resources requires a massive brain and really complex decision making abilities,” she says. “But it does signal that tool technology is integrated into the foraging behavior and the lifestyles of whichever hominin was making it."

These findings offer insight into the daily lives of our ancestors.

"Stone tools provide an opportunity to understand the day-to-day activities and the life of ancient hominins in a way that fossils and other lines of evidence can't quite get at," Finestone says. "Tools are able to show us what hominins were doing on a daily basis, what foods they were eating, where they were ranging, and even what decisions they were making."

The research also suggests that early tool use was far from random or opportunistic, says Finestone, adding that toolmaking was not an on-the-spot solution to a problem that arose right in front of them.

Instead, she says advanced toolmaking was something that took time and effort and was integrated into hominin foraging strategy on a much larger scale than what was previously known in this time period.

"These ancient hominins might have relied on tool technology to a much greater extent than we currently recognize,” Finestone says. “The important aspect, from my perspective, is that early toolmakers seem to have relied on technology and invested in technology in a more human-like way than what we see in other primates."