Paleoanthropologists have documented a bone tool assemblage from a single horizon dated to 1.5 million years ago at Olduvai Gorge in Tanzania. These bone tools precede other evidence of systematic bone tool production by more than 1 million years and sheds new light on the almost unknown world of early hominin bone technology.

Early hominins had already been making tools out of stone in some capacity for at least a million years, but there’s been scant evidence of widespread tool-making out of bones before about 500,000 years ago.

The hominins who shaped the newly-discovered bone tools did so in a manner similar to how they made tools out of stone, by chipping away small flakes to create sharp edges — a process called knapping.

This transfer of techniques from one medium to another shows that the hominins who made the bone tools had an advanced understanding of tool-making, and that they could adapt their techniques to different materials, a significant intellectual leap.

It could indicate that human ancestors at that time possessed a greater level of cognitive skills and brain development than scientists thought.

“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 Dr. Ignacio de la Torre, a researcher at 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.”

“The tools show evidence that their creators carefully worked the bones, chipping off flakes to create useful shapes,” said Dr. Renata Peters, a researcher 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 haven’t seen elsewhere for another million years.”

The 1.5-million-year-old bone tools were discovered at the T69 Complex site in the Frida Leakey Korongo West Gully at Olduvai Gorge, in northern Tanzania, a site renowned for its long history of important archaeological discoveries revealing the origins of humans.

The study authors discovered a collection of 27 bones that had been shaped into tools at the site. The bones mostly came from large mammals, mostly elephants and hippos.

The tools are exclusively made from the animals’ limb bones, as these are the most dense and strong.

The very earliest stone tools come from the Oldowan age which stretched from about 2.7 million years ago to 1.5 million years ago. It employs a simple method for making stone tools, by chipping one or a few flakes off a stone core using a hammerstone.

The bone tools reported in the current study were from the time that the ancient human ancestors were progressing into the Acheulean age which began as far back as about 1.7 million years ago.

The Acheulean technology is best characterized by the use of more intricate handaxes that were carefully shaped by knapping — allowing the production of tools through more standardized means.

The bone tools show that these more advanced techniques were carried over and adopted for use on bones as well, something previously unseen in the fossil record for another million years, much later into the Acheulean age.

Prior to this find, bones shaped into tools had only been identified sporadically in rare, isolated instances in the fossil record and never in a manner that implied that human ancestors were systematically producing them.

Though it’s unclear precisely what the tools were used for, because of their overall shape, size and sharp edges, it’s likely that they may have been employed to process animal carcasses for food.

It’s also unclear which species of human ancestor crafted the tools.

No hominin remains were found alongside the collection of bone artifacts, though it’s known that, at the time, Homo erectus and Paranthropus boisei were inhabitants of the region.

“Because these tools were such an unexpected discovery, we hope that our findings will prompt archaeologists to re-examine bone discoveries around the world in case other evidence of bone tools has been missed,” the researchers said.

Their paper appears today in the journal Nature.

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I. de la Torre et al. Systematic bone tool production at 1.5 million years ago. Nature, published online March 5, 2025; doi: 10.1038/s41586-025-08652-5