Systematic bone tool production at 1.5 million years ago.

Recent evidence indicates that the emergence of stone tool technology occurred before the appearance of the genus Homo and may potentially be traced back deep into the primate evolutionary line. Conversely, osseous technologies are apparently exclusive of later hominins from approximately 2 million years ago (Ma), whereas the earliest systematic production of bone tools is currently restricted to European Acheulean sites 400-250 thousand years ago. Here we document an assemblage of bone tools shaped by knapping found within a single stratigraphic horizon at Olduvai Gorge dated to 1.