Tom Bri:  "...  To argue that australopithicines did not eat meat because
their teeth were
the wrong shape is simply to ignore the fact that every other primate does
eat meat, even if only bugs.   ..."

I cannot remember where/when I heard this, but the theory went something
like this: our species didn't develop carnivore-type teeth because at first
we just scavenged. As brain size increased, we developed sharp tools,
instead of sharp teeth, for killing. Hence the natural selection process
never favored a lion/dog shaped tooth. Does that sound reasonable?