"This discovery leads us to believe that early humans expanded significantly their technological choices, which until this moment was constrained to production of stone artefacts, and now enabled incorporating new raw materials to the repertoire of potential tools", states Ignacio de la Torre, scientist at the CSIC- Instituto de Historia and co-director of the OGAP project. "Additionally, this enhancement of the technological potential hints at advances in the cognitive capacities and mental templates of these hominins (i.e., hominids with a bipedal locomotion), who understood how to transfer technical innovations from stone flaking to bone tool production".
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", de la Torre points out.
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 discovery indicates that, from the Acheulean –period in which the T69 Complex site was formed and where humans already had a primary access to meaty resources–, no longer were animals only dangerous, competitors or just foodstuff, but also a source of raw materials for producing tools", says de la Torre.
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.
"By producing technologically and morphologically standardized bone tools, early Acheulean toolmakers unravelled technological repertoires that were previously thought to have appeared routinely more than 1 million years later", states de la Torre. "This innovation may have had a significant impact on the complexification of behavioural repertoires among our ancestors, including enhancements in cognition and mental templates, artefact curation and raw material procurement", he concludes.
The OGAP project
The Olduvai Gorge Archaeology Project ( OGAP ) is led by Ignacio de la Torre (scientist at the Instituto de Historia, CSIC-Spanish National Research Council and head of the Pleistocene Archaeology Lab ) and Jackson Njau (Indiana University, US), and includes collaborators from several institutions in Spain (CENIEH, UAB, ICREA) and abroad (UK, France, Germany, US, Canada and Tanzania, among others).
Fieldwork at Olduvai by OGAP has been primarily funded by two European Research Council grants ( ORACEAF (Starting Grants, 2012-2016) and BICAEHFID (Advanced Grants, 2019-2026). Research at Olduvai has been possible thanks to the support of the Tanzanian Authorities (Tanzanian Commission of Science and Technology, the Department of Antiquities, the National Museum of Tanzania, and the Ngorongoro Conservation Area Authority) and local collaborators, particularly Maasai communities living around the Olduvai area (which is catalogued by UNESCO as a World Heritage Site).
