Sign up for CNN's Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more.
(CNN)The discovery of 330 stone artifacts in Kenya that date back 2.9 million years is throwing light on a key question in human evolution — who first used stone tools?
Scientists unearthed hammerstones, cores and flakes, and the bones of butchered hippos and two teeth belonging to an ancient humanlike ape known as Paranthropus, from eroded slopes along the shore of Kenya's Lake Victoria at a site called Nyayanga on the Homa Peninsula.
The discovery of a Paranthropus upper and low molar at Nyayanga has undermined the assumption that only humans could make these types of tools.
"While some species of nonhuman primates produce technologies that assist in foraging, humans are uniquely dependent on technology for survival. But the evolutionary origins of this reliance on technology for survival is shrouded in mystery," said Tom Plummer, a professor of anthropology at Queens College, City University of New York, and coauthor of the research.
The most ancient known stone tools are thought to be 3.3 million years old and were discovered at a site called Lomekwi 3, also in Kenya. However, the stone tools unearthed at Nyayanga were more sophisticated than the rudimentary ones found at Lomekwi 3 and belong to a style that had been closely linked to the emergence of the Homo genus that includes our own species, Homo sapiens.
This is the Nyayanga site in July 2014 before excavation. The tan and reddish brown sediments are where Oldowan tools and fossils were unearthed.
Systematically, rather than haphazardly, produced, the stone implements would have allowed ancient hominins to cut through the thick skin of large animals, slice off pieces of meat and break open bones for marrow, as well as mash plant material to make it more palatable, Plummer explained. Hominins were once a diverse group of humans and humanlike apes.
Study coauthor Rick Potts, a paleoanthropologist and Peter Buck Chair of Human Origins at the Smithsonian National Museum of Natural History in Washington, DC, described the tool kit as "the first simple food-processor."
"The sharp-edged flakes could cut as effectively than a lion's set of teeth, and the hammerstones could crush as effectively as an elephant's molars — and thus all of possible foods of the savanna woodlands/grasslands were opened up to processing with this new set of teeth outside of the body," he said via email.
Flakes of stone like this could cut through animal skin.
Prior to this new study, published in the journal Science on Thursday, the earliest known appearance of this style of tools was in the Afar Triangle of Ethiopia around 2.6 million years ago. The tool kit, which archaeologists call Oldowan, after Olduvai Gorge in Tanzania, where artifacts in this style were first found, was a technological breakthrough that humans carried with them widely across Africa and into Asia, enduring for around 1 million years.
"The difference is not exactly like how the iPhone changed how we use phones. I think it's more like how writing changed communication," Potts said via email.
The presence of the Paranthropus molars, however, has suggested that members of the Homo genus weren't the only primates to harness this technological advancement.
"The close association of Oldowan tools, with butchered carcasses and Paranthropus might mean that tool use was more widespread in the hominin family than we ever thought," said John McNabb, a professor of archaeology at the University of Southhampton in the United Kingdom. McNabb was not involved in the research.
Who made the tools?
Paranthropus had a large face, giant jaw and huge teeth that were much bigger than those that belonged to the earliest species of human such as Homo habilis, which had been most closely associated with the emergence of the Oldowan tool kit.