Cutmarks made by stone tools on bones from Olduvai Gorge, Tanzania

Fossils from Olduvai Gorge, Tanzania, show cutmarks which establish that hominids were using stone tools on animal tissues during the Lower Pleistocene in Africa. We identified cutmarks by elimination of other likely causes of the marks on the bone surfaces, for example, gnawing or chewing by carnivores or rodents, and damage made by tools of excavators or preparators. This was achieved by comparing the marks on the fossils with those produced by known causes on modern bones, using scanning electron microscopy (SEM). Because the fossils occur as part of accumulations of animal remains in relatively undisturbed geological contexts, we conclude that there is a functional association between the stone artefacts and bones at these sites, rather than an accidental, postmortem association^1,2.