Tom Bridgeland wrote:

>> ... a lot more glucose energy..
> Or fat? Where would proto humans get all this extra glucose that
> chimps, gorillas and baboons don't? Baboons in particular live in
> conditions that proto humans were said to occupy, the open savannah.
> Baboons eat a lot of roots, mainly grass rhizomes from what I have read.

The difference would be the stick - a digging stick.
There are a lot of deeper tubers occuring in the savannah than only
grass rhizomes.
If you read "the raw and the stolen", printed in "current anthropoligy,
vol 40 #5, Dec 1999" you find that these items present a big energy
reserve in the savannah.
"...
Thus, surveys of the number of species with
edible underground storage organs yield a total of 101 for
five African savanna sites compared with 14 for four forest
sites (....). The four major plant families represented by these species
in the African sites were Asclepiadaceae, Leguminoseae,
Cucurbitaceae, and Liliaceae,.."

Wrangham's theory goes on to suppose the early usage of fire - as early
as 2 mio years ago, exactely when rainforest turned to savannah (ice-age
onset) and first hominids appeared.
Fire makes more tubers edible and easier digestible (that would make the
second difference to baboons then).

Fat -- isn't a energy source for the brain, except for half the
requirement and only when in ketosis. Even small amounts of carbs
"throw" humans out of ketosis -- as many of you know.
If yould would assume that savannah-hominids were permanentely in
ketosis (like Inuit), then they would have to reach a 50/50% ratio of
fat to meat - or at least some 30/70. But such savannah wild game has
only some 4% fat - not 30.
They could only have eaten a small percentage of the antelope carcasses
and discard most of it.
And they would have had to nearly avoid all plant food.

Likely?

Amadeus