Tool-using strategies by early hominids at bed II, Olduvai Gorge, Tanzania.

This study examines the current prevailing model of Oldowan technology-the opportunistic, least-effort strategy of stone tool making and using by early hominids. The sample includes the MNK chert factory site and three contemporaneous assemblages from Olduvai Gorge, all dated between 1.65 and 1.53 m.y.a. The analysis suggests that early hominids at Olduvai may have been selective, applying distinctive strategies in making and using tools depending on the different types of raw materials available to them. The preponderance of lava cores and near absence of flakes associated with the cores suggest that lava cores at Olduvai did not provide a source of flakes. They were primarily heavy-duty core tools, despite the fact that the majority of Olduvai lava is of excellent quality for flaking. Contrary to this pattern, the abundance of chert flakes and the lack of large chert cores suggest that the production of flakes was the most important strategy applied to chert. Original forms and flaking mechanics of the raw materials may have been important factors in the simultaneous application of the different, complementary strategies. The Oldowan tool-using strategy was dynamic and flexible, in response to changes in raw material availability. The use of chert between 1.65 and 1.53 m.y.a. was apparently related to the drastic decrease in flake production in lava and quartz. Finally, lack of initial reduction episodes of lava material challenges the idea of the stone cache strategy at Olduvai between 1.65 to 1.53 m.y.a.