An international research team led by archaeologists from Spain and the United States discovered ancient tools made from animal bones at the oldest known residence of humanity in East Africa, Tanzania. While tools made from animal bones have been found before, this is the first time tools systematically made in a uniform manner and size have been excavated in large quantities.
A joint excavation team led by the Historical Research Institute under the Spanish National Research Council (CSIC), the University of Indiana in the United States, and University College London announced in the international journal Nature that they found evidence of systematic tool-making from animal bones by hominins living in the Olduvai Gorge in northern Tanzania 1.5 million years ago, utilizing stone-flaking technology.
Humans, called 'Homo faber' or 'tool-making humans,' possess the unique ability to create tools unlike other animal species. It is estimated that 6 million years ago, human ancestors were much closer to monkeys, crushing nuts with stones or catching termites with sticks. Archaeologists discovered the first stone tools 3.3 million years ago. At that time, human ancestors shaped tools by striking a stone against another stone to create comfortable forms. It is estimated that these stone tools were primarily produced from 2.7 million to 1.5 million years ago. Bone tools appeared much later, between 500,000 to 250,000 years ago in Europe.
In 2018, the research team excavated the T69 site in the Olduvai Gorge, Tanzania, discovering a hand axe made from elephant limb bones and 27 tools made from hippopotamus limb bones. These bone tools were found to have been made 1 million years earlier than those reported in other regions. The elephant bones used as materials measured 22 to 38 cm in length and 8 to 15 cm in width, while the hippopotamus bones, which were used to create slightly smaller tools, measured 18 to 30 cm in length and 6 to 8 cm in width.
The tools showed signs of having been sharped using stone flakes. According to the research team, the hominins who crafted these bone tools likely inhabited the area at that time. They discovered an elephant carcass and cut one of its massive limbs. Then they broke the bone fragments to create sharp edges. The research team believes tools makers at the time applied the same expertise accumulated from previous stone tool-making processes. The technology used for striking stones was likely beneficial for carving the hard and sturdy large bones of large animals.
It appears that the tool makers acted with considerable caution and adherence to certain principles when crafting tools. They handled the bones carefully, leaving evidence of efforts to break fragments in order to create useful shapes. Signs of systematic attempts to produce bone tools are also apparent. The research team observed that creating sharp edges likely required relatively sophisticated techniques for splitting small fragments. They noted, “It is likely that as hominins began making bone tools, they developed abstract reasoning skills, including the ability to identify patterns, make connections, and think critically.”
The tools made from animal bones were discovered during excavation surveys conducted in the Olduvai Gorge from 2015 to 2022. The research team had previously carried out field surveys in the region between 2010 and 2011, during which they found hominin teeth at the surface and conducted intensive investigations in the area. While digging in the gorge, the researchers discovered thousands of fossils of hippopotamuses, crocodiles, and fish. These animals are estimated to have lived in nearby ponds or lakes about 1.5 million years ago. They found cut marks on hippopotamus bones along with over 10,000 stone tools, followed by various tools made from hippopotamus and elephant bones.
This region has been referred to as the 'cradle of humanity' due to discoveries of various hominin bones dating back from about 2 million to 20,000 years ago, including Homo habilis, Homo erectus, and Homo sapiens. Additionally, various artifacts, including stone tools made by human ancestors, have been found in concentration. The Oldowan stone tool culture that originated in the Olduvai Gorge led to the more sophisticated Acheulean stone tool culture.
Early human ancestors who practiced hunting and gathering likely made and used tools from animal bones. In some areas inhabited by hominins, it is presumed they began making tools from bones obtained from animal carcasses due to a scarcity of stones. However, because animal bones are organic and decompose easily, it has been difficult to find traces of them.
There have been previous instances of bone tools discovered in some isolated settlements in Europe and Asia, but the research team and experts believe that the 27 animal bone tools reported from the Olduvai Gorge suggest the possibility of mass production, which sets them apart from those in other regions. The bone tools found in the Olduvai Gorge are more rudimentary compared to those made in Europe 400,000 years later. However, the research team assessed that they were likely more suitable for tougher tasks.
The research team stated that they do not currently know exactly who made these tools. While only bone tools were found in the gorge, no hominin remains that could suggest manufacturers or users were discovered. Previous studies indicate that Homo erectus and a type of hominin called Paranthropus boisei likely inhabited the area, making them the probable creators and users. The researchers added that it is still unclear for what purpose these tools were used, but it is highly likely that the human ancestors used them to dismantle animal carcasses for food and to create new tools.
Research on the tools used by early human ancestors has primarily focused on stone tools. Dr. Ignacio de la Torre, who led the current study from the Historical Research Institute of the Spanish National Research Council, mentioned that he had not expected human ancestors to have made bone tools until recently. This study suggests that tool-making was gradually becoming an important aspect of life for human ancestors.
Dr. de la Torre noted, “The brains of the hominins at that time were already sophisticated enough that they could do more than merely conjure images of specific tools from nearby stones.” He added that it is likely that other bone tools are waiting for archaeologists in other ancient sites across Africa. Jackson Nyao, an associate professor at the University of Indiana and co-author of the study, stated, “The discovery of tools made from animal bones sheds new light on the previously little-known bone tool technology of hominins.”
References
Nature(2025), DOI : https://doi.org/10.1038/s41586-025-08652-5