dem bones Prehistoric bone tool cache suggests advanced reasoning in early hominins Tools "show evidence that their creators carefully worked the bones, chipping off flakes to create useful shapes." Jennifer Ouellette Mar 6, 2025 1:14 pm | 1 An elephant humerus that has been knapped into a tool. Credit: CSIC An elephant humerus that has been knapped into a tool. Credit: CSIC Story textSizeSmallStandardLargeWidth *StandardWideLinksStandardOrange* Subscribers only Learn moreOlduvai Gorge in northern Tanzania boasts sediment layers dating back to about 1.8 million years ago. Those layers contain simple stone tools that marked one of the earliest recorded technological transitions. Now, researchers have uncovered a substantial cache of prehistoric bone tools in the same region dating back 1.5 million years. It's the oldest collection of mass-produced bone tools yet known, according to a new paper published in the journal Nature. And while it's still unclear which hominin species crafted the tools, the discovery suggests that our early human ancestors had some advanced reasoning skills a good million years earlier than previously thought.The tools show evidence that their creators carefully worked the bones, chipping off flakes to create useful shapes," said co-author Renata F. Peters, an archaeologist at University College London. "We were excited to find these bone tools from such an early timeframe. It means that human ancestors were capable of transferring skills from stone to bone, a level of complex cognition that we havent seen elsewhere for another million years.As previously reported, species on the hominin family tree have made and used stone tools for about 2.6 million years. For instance, Homo habilis was an early member of our genus who walked upright and had a mixture of human and ape-like features. Starting around 1.2 million years ago, a later hominin species called Homo erectus made more complex stone tools, like hand axes.Olduwan tools are mostly sharp flakes and very basic tools for chopping, scraping, and pounding. Theyre much less complex and precise than the tools made by later hominins, like Neanderthals, who chipped small flakes off carefully prepared stone cores. Geochemical analysis of the tools at Ewass Oldupa suggests that hominins there gathered some of their quartzite locally and ventured up to 12 kilometers (7.5 miles) away for the rest. They seemed to choose different materialsin some cases, as specific as choosing slightly different types of quartzite from different outcropsfor particular tools.A 2020 study also suggested that the earliest toolmakers in our family tree knew enough to choose their materials wisely. Granted,H. habilis didnt carefully measure how much force it took to cut a limb off a freshly killed antelope and then draft plans for a more efficient blade. But it seems that they noticed which materials made sharper blades and which ones offered a trade-off between sharpness and durability and then applied that knowledge to making tools. That's no small cognitive feat.A prehistoric bone tool factory Credit: CSIC Bone tools shaped by knapping, however, were much rarer until about 500,000 years ago, according to Peters and her fellow authors, making it challenging to identify consistent behaviors in the making and use of such tools. That is now changing with the discovery of a bone tool collection at the T69 Complex at Olduvai Gorge, specifically seven trenches excavated between 2015 and 2022. In addition to over 10,000 stone tools, there were abundant fish, crocodile, and hippopotamus remains, as well as those of elephants and rhinoceroses.Among all the fossils and bone fragments, the authors identified 27 specimens that were clearly bone tools, evidenced by signs of intentional flake removal, shaping, and modification of bone edges to produce an elongated shape. The authors acknowledge that other non-intentional factors can cause such flaking, particularly the gnawing of carnivores. But carnivores made up less than 1 percent of the identified animal remains at the site and the 27 specimens did not show clear signs of such gnawing.It seems the hominins who made the bone tools carefully selected the bones of large mammals, most commonly elephant and hippopotamus. "Precise anatomical knowledge and understanding of bone morphology are suggested by preference given to thick limb bones and the application of recurrent flaking procedures," the authors wrote. These large, heavy bone tools may have been later replaced by larger stone tools, which might explain why they became so rare after the emergence of systemically produced lithic hand axes.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 co-author Ignacio de la Torre of the CSIC-Spanish National Research Council. At the same time, this expansion of technological potential indicates advances in the cognitive abilities and mental structures of these hominins, who knew how to incorporate technical innovations by adapting their knowledge of stone work to the manipulation of bone remains.Nature, 2025. DOI: 10.1038/s41586-025-08652-5 (About DOIs).Jennifer OuelletteSenior WriterJennifer OuelletteSenior Writer Jennifer is a senior writer at Ars Technica with a particular focus on where science meets culture, covering everything from physics and related interdisciplinary topics to her favorite films and TV series. Jennifer lives in Baltimore with her spouse, physicist Sean M. Carroll, and their two cats, Ariel and Caliban. 1 Comments