Some time after 3.0 million years ago we find a distinct
split within the hominid 
fossils.
There were clearly two paths that hominids embarked upon at some point in
time that became very clear by about 2.5 million years ago. This divergence
was first recognized in southern African fossils in the 1920s and 1930s
by Robert Broom and Raymond Dart. Louis B. Leakey and Mary Leakey found
similar evidence of this divergence in Olduvai Gorge in the 1950s. A larger
and more robust form of Australopithecine once co-existed side by side with
hominids that eventually evolved into us. These forms have been referred
to by a number of names such as Zinjanthropus (affectionately known
as "Zinj Man", the upper image to the right), Paranthropus,
Australopithecus robustus, and Australopithecus boisei. For
our purposes here we will mainly speak of them as the robust australopithecines.
For all practical purposes they are a version of hominid that not only diverged
from forms that we can trace within our ancestry in a very direct path but
became highly specialized. Alan Walker once referred to them as the "Human
Cuisinart" because of this adaption. The focus of their evolution was
on chewing and in a way they became bipedal gorillas exploiting vegetation
on the African savannas.
