The oldest collection of prehistoric bone tools from Olduvai Gorge, mass-produced by hominins during the transition from Oldowan to Acheulean
Prehistoric bone tool ‘factory’ hints at early development of abstract reasoning in human ancestors
The oldest collection of mass-produced prehistoric bone tools reveal that human ancestors were likely capable of more advanced abstract reasoning one million years earlier than thought, finds a new study involving researchers at UCL and CSIC – Spanish National Research Council.
The paper, published in Nature, describes a collection of 27 now-fossilised bones that had been shaped into hand tools 1.5 million years ago by human ancestors.
It’s the earliest substantial collection of tools made from bone ever found, revealing that they were being systematically produced one million years earlier than archaeologists once thought.
Early human ancestors known as hominins (human ancestors who could walk upright) 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 toolmaking out of bones before about 500,000 years ago.
The hominins who shaped the recently-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 toolmaking, 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.
Co-author Dr Renata F. Peters (UCL Archaeology) said: “The tools show evidence that their creators carefully worked the bones, chipping off flakes to create useful shapes. 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.”
Lead author Dr Ignacio de la Torre of the CSIC-Spanish National Research Council added: “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.
“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 were discovered in Olduvai Gorge in Tanzania, a site renowned for its long history of important archaeological discoveries revealing the origins of humans.
The researchers found 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 tools originate from a time in prehistory where early hominin cultures were undergoing one of the first ever technological transitions.
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 this 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 characterised by the use of more intricate handaxes that were carefully shaped by knapping – allowing the production of tools through more standardised 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 artefacts, though it’s known that, at the time, our human ancestor Homo erectus and another hominin species known as Paranthropus boisei were inhabitants of the region.
Because these tools were such an unexpected discovery, the researchers hope that their findings will prompt archaeologists to re-examine bone discoveries around the world in case other evidence of bone tools has been missed.
This research was supported by the European Research Council (ERC).
Press release from University College London – UCL.
New discoveries reveal systematic Production of bone tools 1.5 million years ago
Before this discovery, led by a CSIC team, it was thought that the systematic use of bone tools happened a million years later.
Evolutionary keys
Eastern Africa contains the earliest evidences of tool use and production among the first Genus Homo ancestors. The best known is the Oldowan culture, named after the stone artefacts first discovered at Olduvai Gorge. The Oldowan spanned between 2.6 and 1.5 million years ago, and is characterised by the production of stone sharp flakes through striking two rocks against each other. This relatively simple technology led to a new culture emerging 1.7 million years ago, i.e., the Acheulean, that lasted until 150k years ago.
The Acheulean technology is well known by the conspicuous presence of handaxes, which are large, robust, often pointed and almond-shaped stone artefacts, and whose production requires remarkable technical ability.
“Prior to our discovery, the technological transition from the Oldowan to the Acheulean was limited to the study of stone tools”, points out Ignacio de la Torre, scientist at the CSIC- Instituto de Historia and co-director of the OGAP project.
For hundreds of thousand years, early humans had seen the animals they co-existed with at the African savannahs either as a hazard, for there is evidence that often humans were preys to felids and large birds–; as competitors, for our ancestors rivalled with hyenas and vultures to access carcasses hunted by large felids; or as a source of proteins, which our ancestors obtained mostly from bone marrow in prey leftovers abandoned by carnivores.
Our results demonstrate that at the transition between the Oldowan and the early Acheulean, East African hominins developed an original cultural innovation that entailed a transfer and adaptation of knapping skills from stone to bone.
Press release from the Spanish National Research Council – CSIC.
New findings reveal systematic production of bone tools 1.5 million years ago
Before this discovery in the Olduvai Gorge (Tanzania), in which CENIEH is involved, it was thought that hominins only manufactured bone instruments sporadically. This practice may have impacted the development of more complex cognitive patterns and the standardization of a new set of behaviors among early humans.
Alfonso Benito Calvo, a researcher at the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) is part of an international team led by the Consejo Superior de Investigaciones Científicas (CSIC), which has just published a paper in the journal Nature on the Olduvai Gorge (Tanzania), which reveals that the production of bone tools 1.5 million years ago was methodical and systematized.
This research is a milestone in the archaeology of human origins because before discovering this set of bone tools in the excavations of the T69 Complex site of Olduvai, it was thought that the manufacture of this type of instrument was practically unknown among our most remote ancestors.
“This discovery suggests that the first humans significantly expanded their technological options, which until then were limited to the production of stone tools, and in turn, this indicates advances in the cognitive abilities and mental structures of these hominins (hominids with bipedal locomotion), who knew how to incorporate technical innovations, adapting their stoneworking techniques to working with bone remains,” explains Ignacio De la Torre, CSIC researcher at the Instituto de Historia and co-director of the excavation.
CENIEH geologist Alfonso Benito Calvo was responsible for the geological analysis of the site, mapping and analyzing each layer of sediment, as well as applying various statistical studies to decipher the processes that led to the accumulation and preservation of such an abundant and spectacular archaeological site.
“The site was formed on the eastern bank of Olduvai Paleo-Lake, where heavy rains caused a flood that inundated the lakeside plain. As the flood waters slowed down, they deposited their suspended sediment, burying the entire archaeological complex,” says Alfonso Benito.
Stone tools, the key to an evolution
In East Africa, there is the oldest evidence of the use of tools by the first ancestors of the Homo genus. The most famous is the Oldowan culture, named after the artifacts found in the Olduvai Gorge. The Oldowans lived between 2.5 and 1.5 million years ago. This relatively simple technology gave rise about 1.7 million years ago to a new culture: the Acheulean (which lasted until 150,000 years ago). Until this discovery, the transition from the Oldowan to the Acheulean culture was known almost exclusively through stone artifacts.
“Our discovery indicates that, from the beginning of the Acheulean, the period in which the T69 Complex in the Olduvai Gorge was formed and in which it is evident that humans already had primary access to meat resources, animals were no longer only a source of danger, competition or proteins, but also a source of raw materials with which to make tools,” says De la Torre.
The results of this study demonstrate that, during the transition from Oldowan to Acheulean technology, East African hominins developed a cultural innovation that involved the transfer and adaptation of carving skills from stone to bone.
“By producing technologically and morphologically standardized bone tools, early Acheulean carvers developed technological repertoires that were previously thought to have appeared routinely more than 1 million years ago,” says De la Torre. “This innovation could have had a significant impact on the behavioral and adaptive potential of early humans, including improvements in their cognitive abilities, technological development and the acquisition of raw materials,” he adds.
The OGAP Project
The Olduvai Gorge Archaeology Project (OGAP) is led by Ignacio de la Torre (researcher at the Instituto de Historia and head of the Laboratorio de Arqueología del Pleistoceno, CSIC) and Jackson Njau (Indiana University, USA), and has partners from several institutions in Spain, including CENIEH (in addition to UAB and ICREA) and other countries (United Kingdom, France, Germany, USA, Canada and Tanzania).
Since 2010, OGAP has organized 19 excavation campaigns in Olduvai, many of them investigating the transition between the Oldowan and the Acheulean, a transition that is largely linked to the study of Homo habilis and its evolutionary successor, Homo erectus. Between 2015 and 2022, OGAP researchers dedicated a significant portion of their efforts to excavating the T69 Complex, discovering, restoring and analyzing the bone tools written about in Nature.
The scale and intensity of OGAP’s fieldwork have been made possible by two grants from the European Research Council awarded to De la Torre, ORACEAF (Starting Grants, 2012-2016) and BICAEHFID (Advanced Grants, 2019-2026); and, above all, thanks to the support of the Tanzanian authorities and local partners, especially the Maasai communities around Olduvai, who work closely with OGAP researchers in the discovery and study of the paleoanthropological treasures of the Olduvai Gorge, which is recognized as a UNESCO World Heritage Site.
Bibliographic information:
de la Torre, I., Doyon, L., Benito-Calvo, A. et al. Systematic bone tool production at 1.5 million years ago, Nature (2025), DOI: https://doi.org/10.1038/s41586-025-08652-5
Press release from Centro Nacional de Investigación sobre la Evolución Humana – CENIEH
