Researchers find 3 million-year-old tools in Kenya, showing the development of human ancestors

On a peninsula of the lake in East Africa, archaeologists have found clues about a society that lived there more than 3 million years ago.

Kenya’s Homa Peninsula is part of East Africa’s Rift Valley, a part of the world often called “the cradle of humanity.” Many of the oldest clues about the first days of humanity were preserved under the fertile and human soil of the valley, including the remains of “Lucy”, a ancient human relative who lived more than 3 million years ago.

Tom Plummer and his team are the latest to make discoveries in the area, working at a site on the peninsula called Nyanga. The team found flakes, or small knives, at the dig site. Blades are believed to be some of the first tools ever used on Earth – and even after more than 3 million years, they still have a sharp edge.

Plummer, an archaeologist at the City University of New York, said the blades were made by hammering a stone against each other. The knives were used to peel and cut fruits and vegetables, and to cut the meat of prey such as hippos, Plummer said. The meat was then weighed between the stones to tenderize. The knife and stones are known as the Oldowan toolkit, and likely set the stage for further technological advancement.

“I think Oldowan technology is probably the most important technological innovation that has ever happened in human history,” Plummer told “CBS Saturday Morning.”

“It allowed (pre-human ancestors) access to a wide range of foods that they never had access to before.”

Plummer said the new diet would have fueled the body and brain growth, starting a “feedback cycle” that created more sophisticated beings that “started doing more with technology.” A similar, even older, cutting tool was also found in Kenya, but that technology apparently died out, so Plummer believes that this tool is the one that can be credited for those developments.

“I think it all starts with the Oldowan,” Plummer said.

Who made the tools is another surprise. Along with the tools, Plummer’s team found the tooth of a paranthropus, an early hominin that is not a direct ancestor of humans. This suggests that the first tool-making is not a human legacy, but an idea that the ancestors of humanity copied, then used to dominate other hominins, who eventually died out.

Rick Potts, director of the Smithsonian’s Human Origins Program and head of research on the peninsula, said the discovery may it helps frame human existence on the planet.

“We’re the last bipeds standing, as I call it,” Potts said. “All those other ways of life have become extinct. And so it gives us a lot to think about, and draws attention to the fragility of life, even in our journey through time.”

The search for pre-human history

The search for these first artifacts has the look and intrigue of an “Indiana Jones” movie. Finding splintered rocks that showed evidence of being used as tools was one thing, but the archeology team found cut marks on animal bones that confirmed how knives were used.

Blasto Onyango, a local archaeological legend who helped uncover the Turkana Boy, the most complete hominin skeleton ever discovered, said his impressive find took “four or five years” to find. As time passed, he and other archaeologists found “different parts of the” skeleton, slowly but surely working to uncover the remains of a child who lived more than a million and a half years ago.

Paleontological researcher Rose Nyaboke said the kind of painstaking, slow research is what makes an archaeological dig’s day’s work. Sometimes, she and other researchers find small pieces of bone, but they have to leave those fragments where they were found.

“We don’t just pick something. It has to have paleontological significance,” explained Nyaboke. “We say ‘Sorry.’ We can’t pick you up today.”

The bones that matter are those that can lend context to the area, such as pig teeth. Pigs evolved so quickly their skeletons help date the surrounding area. The site is too old for carbon dating, and the ancient volcanic ash that preserved the artifacts makes other dating methods too difficult to use. The area had been largely abandoned by researchers after artifacts from the Homa Peninsula led to inaccurate claims about human origins. Despite everything, Potts began digging on the peninsula nearly 40 years ago.

“We have found a place that is difficult to date, but we have not left, because science takes persistence,” said Potts.

That persistence has been rewarded with discoveries like Plummer’s. New technologies have made the sites easier to date, and new discoveries in East Africa have refined researchers’ understanding of human roots. Researchers knew that modern homo sapiens emerged in Africa about 300,000 years ago, but it wasn’t until recently that they realized that their hominin ancestors started walking on two legs at least 6 million years ago .

“Some of the things that we thought happened in a very short period of time, in the last one million years, are now spread out over a period of 6 million years,” Potts said. “This includes making tools.”