Abstract

A number of natural processes occurring during the life of an animal or after its death can produce pseudotools, mimics of human-made objects. A number of purported bone tools from Lower and Middle Palaeolithic sites have been published without any validating microscopic analysis of the bone surfaces showing possible traces of manufacture and use. This paper discusses the evolutionary significance of bone tool technology and summarises results of research on the use of bone tools by early hominids between one and two million years ago (Mya). It attempts to establish formal criteria for the identification of minimally modified bone tools by characterising the modifications produced by known human and non-human agents, and applying these criteria to the purported bone tool collections from Swartkrans, Sterkfontein and Olduvai Gorge. A number of experiments involving a variety of tasks were conducted in order to increase the range of diagnostic features available. New analytical techniques have been developed for the quantification of microscopic use-wear, and a wide range of taphonomic and morphometric variables have been used to isolate idiosyncratic populations of specimens for which a robust argument can be made for their identification as tools. South and East African early hominid sites dated to between 1,8 Mya and 1 Mya have yielded what appear to be very different types of bone tools. The former are characterised by long bone shaft fragments and horn-cores of medium to large-sized bovids, collected by hominids after weathering, and possibly used in specialised digging activities. Most fragments were used as such, though a few horn-cores were modified by grinding the tips to points on sandstone or compact abrasive sediment. Those from East Africa mainly consist of freshly broken, or more rarely, complete irregular bones from very large mammals, used as such, or modified by flaking. Irregular bones or epiphyses appear to have been used as hammers, while the others were apparently involved in a variety of light- and heavy-duty activities. Based on the bone tool manufacturing techniques recorded in the two regions, there appear to be no significant differences between the cognitive abilities of the hominid users.