——s 
Fig. 6. Upper dentition of OH 13, one of the fragments from Olduvai Gorge 
assigned to Homo habilis. About 1.6—1.5 myr old. Scale is 1 cm. 
species was based was ascribed to our own genus largely because 
it was plausibly associated with the crude stone tools found in the 
lowest layers of the Gorge, and because there were indications of a 
brain vault a bit bigger than that typical for the early hominids— 
even if there were not a lot of other identifiable physical differences. 
Since then the plot has thickened, and a variety of fragmentary “‘ear- 
ly Homo”’ fossils have been identified in eastern Africa in the period 
between about 2.5 and 2.0 myr ago, just as have several sites yield- 
ing early stone tools. We have yet to obtain a firm association be- 
tween such tools and hominid(s) who made them; more than one 
species may well have been involved. But it is a fair bet that the 
first stone toolmaker was physically of fairly archaic body build and 
possessed of a brain not a lot bigger than you might expect of an 
ape of his or her body size. And if so, we have here a good example 
of a theme we find consistently throughout the hominid record: be- 
havioral innovations do not tend to be associated with new kinds of 
humans. If you think about it, this makes considerable sense, for a 
new technology must be invented by an individual who cannot differ 
12 
