buried millions of years ago in Kenya are perhaps the oldest example of the technological prowess of our ancestors. The tools recently discovered on the Homa Peninsula in Lake Victoria are now the earliest known examples of Oldowan technology — stretching its known start date back as much as 400,000 years.
The Oldowan Toolkit
“[Oldowan] is a true benchmark for our technology,” says paleontologist Rick Potts, director of the Human Origins Program at the Smithsonian National Museum of Natural History in Washington, D.C., and co-author of the new study, published in Science.
“Oldavian toolkit” is a term anthropologists use to describe a distinct technology that existed millions of years ago Homo sapiens ever walked the Earth. These tools usually involve very controlled rock flaking.
Striking one stone against another, ancient hominins broken off in sharp, thin pieces, leaving a sharp-edged stone behind that would be good for cutting or scraping. Grids can also be used as sewing materials and other things.
The name of the technology comes from the Olduvai Gorge in Tanzania, where archaeologists found bones and tools of ancient hominins during several excavations beginning in 1910. Some of these bones date back to about 2.1 million years ago.
Since then, tools that fall into this categorization have been found widely in Africa and even in Europe and East Asia.
Mining at Nyayanga
The Nyayanga excavation site, where the stone tools were found, is a lush, tropical site with deep ravines. As these gullies erode, extremely old layers of dirt and sediment—and sometimes ancient fossils and tools—are exposed.
Potts, who has been exploring the area since 1985, says “this is an area ripe for big discoveries.”
More recently, he and his study co-authors found that the 330 stone tools they found at Nyayanga date back between 2.58 million and 3 million years. This is hundreds of thousands of years older than the previous oldest known set of Oldowan tools, which were found in Ethiopia.
“We’re seeing a real sea change in terms of our understanding,” says Potts.
The site also revealed 1,776 animal fossils, including those of at least three hippos and antelope. The bones of two of the hippos show signs of slaughter, including a rib cut and four parallel scars on the shin; some of the antelope bones show abrasion.
A separate analysis the researchers performed on stone flakes found in the area indicated that they were likely used to scrape, cut and strike animals and plants. “The surprising discovery is that this ancient technology was used for more than just cutting up animals,” says Potts.
It remains unclear, however, whether these ancient tool users killed the animals themselves before butchering, or whether humans simply scavenged carcasses.
Whose tools are they?
Likewise, the question of who made these tools in the first place is not entirely clear – although there are a few suspects.
Researchers have long assumed that tool use is limited to Homo genus The oldest known fossil depicting this is a 2.8-million-year-old jawbone known as LD 350-1 found in Ethiopia. This timeline lines up pretty well with the Nyayanga toolkit.
Read more: When did Homo sapiens first appear?
But perhaps even more compelling is the evidence found inside Nyayanga itself, in the form of two molars that the team identified as belonging to Paranthropus. This genus is a close relative of Homo genus, but some researchers speculate that because of its powerful jaws, Paranthropus they would not need tools to help break down their food.
“It was basically a chewing machine in its own right,” Potts says of their jaws, though he believes the debate is ripe for re-examination based on these latest findings.
Finally, a third possible hominin discovered around this time is Australopithecus. The most famous of these, Lucy, died in Ethiopia and dates to approximately 3.2 million years ago, while the most recent Australopithecus the specimens date back to about 2.9 million years ago.
Read more: The Death of Lucy: What Killed the Most Famous Fossil
Each of these three hominins may have used the stone tools found at Nyayanga. But until more bones are found, it’s hard to say definitively.