Fig. 4. Upper dentition of Paranthropus boisei (OH 5) from Olduvai Gorge, 
Tanzania. About 1.8 myr old. Scale is 1 cm. 
portant to note that, bipedalism aside, there is very little to indicate 
that the early hominids were functionally hominid in other respects. 
True, we see some typically hominid innovations very early on, such 
as both absolute size reduction of the canine teeth, and the elimi- 
nation of the canine size differential between the sexes that is typical 
of the great apes. But these early hominids still had apelike cranial 
proportions, with large, projecting faces hafted onto small braincases 
(which housed brains little, if any, larger than those of apes, even 
if body size is factored in: fig. 3). And indeed, there is a strong 
tendency among paleoanthropologists today to refer to these ances- 
tral early hominids as ‘bipedal apes.” 
In the period between 4 and 2 myr ago these creatures flourished 
widely in Africa, giving rise to several species in two major lineages 
10 
