A discovery at Tanzania's Olduvai Gorge pushes back the timeline of early human tool-making by nearly a million years, according to a study published in Nature. A team of archaeologists led by Ignacio de la Torre from the Spanish National Research Council (CSIC) in Madrid unearthed 27 standardized bone tools, mostly from hippopotamuses and elephants, indicating systematic production. The tools, dating back 1.5 million years, suggest that early humans were using animal bones to make cutting implements, an advancement in tool-making.
The bone tools measure up to around 16 inches (40 centimeters), with the largest being a sharp blade made from the humerus of an elephant. Sixteen out of the 27 tools could be linked to specific animal species, including elephants and hippos, as reported by Science News. The tools were likely made by breaking off the thick ends of leg bones and using a stone to knock off flakes from the remaining bone shaft, similar to the process used in creating stone tools.
"It has always been thought that the Acheulean was characterized, almost exclusively, by the invention of stone hand axes, and our discovery shows that the innovations of this period also include the beginning of systematic work in bone," said Ignacio de la Torre, according to El Confidencial. This discovery evidences a "qualitative leap in the cognitive abilities" of Homo erectus, who were systematically making bone tools alongside stone implements.
The T69 Complex faunal assemblage at Olduvai Gorge had been visited and excavated seven times between 2015 and 2022. Archaeologists found lithic tools and remains of animals consumed by humans, including more than 10,000 stone tools and numerous bone tools shaped on-site from hippopotamus bones, as reported by Reuters. No ancient human fossils were found at the site, but the researchers suspect that Homo erectus was responsible for the butchering of the animals whose bones were used for tools.
"This discovery leads us to assume that early humans significantly expanded their technological options, which until then were limited to the production of stone tools and now allowed new raw materials to be incorporated into the repertoire of potential artifacts," said de la Torre, according to CNN. The uniform selection of large and heavy leg bones from specific animals and the consistent pattern of alteration makes it clear that early humans deliberately chose and carved these bones, reflecting a practiced methodology and strategy.
The discovery pushes back the date for ancient bone tool use by around one million years, revealing that hominins had "rather more complex tool kits than previously we thought," according to Popular Science. Previously, evidence of widespread toolmaking from bones was scant, with the first evidence of systematic production only recognized in Europe around 400,000 years ago. Bone tools are less commonly found because bone usually decays over time, and how many more bone tools were deposited but decomposed in the interim can only be guessed.
Renata Peters, a study co-author and archaeologist at University College London, said, "It means that human ancestors were capable of transferring skills from stone to bone, a level of complex cognition that we haven't seen elsewhere for another million years". The addition of bone implements reflects a recognition that animals can provide a source not only of meat but also of raw materials. "The tools, mainly made from bones freshly collected from carcasses, shed new light on the almost unknown world of early hominin bone technology," said de la Torre.
Olduvai Gorge, often referred to as the Cradle of Humankind, has advanced our understanding of early human life and tool use, with evidence of systematic bone tool production by hominids. The Acheulean culture, which emerged around 1.7 million years ago, is well known for its hand axes and almond-shaped stone artifacts, representing an innovation in tool-making. This discovery reveals that ancient humans had a greater comprehension of toolmaking, suggesting greater cognitive abilities than previously believed, and may change the understanding of when they started using crafted bone as tools.
The article was written with the assistance of a news analysis system.