Todd Moody wrote:  
> One of the premises of the whole paleodiet idea is that ancient humans had to
have figured out how to survive in the grasslands, where no other primates
live.  

The fundamental idea may itself be wrong.   In Nutrition and Evolution,
Crawford and Marsh argue convincingly (I'm convinced, anyway), that humans
do not show adequate adaptation to an arid savannah environment, but show
many characteristics of adaptation to a semi-aquatic coastal life, and that
the primary evolutionary habitat of humans has been coastal areas, where in
fact most humans still live today.

Several of the points against savannah hypothesis and in favor of coastal
hypothesis:

1)  We are water wasters, whereas most savannah species are water
conservers.   In few hours on a savannah, a human can lose several gallons
of water in sweat.  Profuse sweating does not make much sense in an arid
environment.  C & M state:  "Perspiration is not a technique the savannah
animals employ:  it is too expensive, except for an animals like the
hippopotamus which does sweat but makes up for it by sitting in water or mud
during the heat of the day and feeding only at night."
2)  Humans have lost most body hair--a trait shared with some aquatic
mammals, whereas grassland animals--except those water-going species like
the hippo--are covered with hair.
3. At birth, man has an abundance of ³baby fat², and as an adult, man has
subcutaneous fat; this kind of fat is found in sea mammals but not in other
primates nor grassland animals in general.
4.  Humans have a large number of eccrine glands in the skin, a
characteristic shared with water-going animals like the hippo, whereas
monkeys and apes have few of these glands.
5.   Like other semi-aquatic animals, but unlike obligatory land animals,
humans have a natural diving reflex (the heart rate declines as soon as the
head is submerged) and a remarkable ability to swim, unlike grassland
animals.  Human infants can swim spontaneously, with no instruction, at
birth (and before six months of age).  Adult humans are capable of diving to
a depth of 150 feet, and of swimming long distances, such as across the
English Channel,  without any equipment, a feat impossible to any savannah
species.   
6.  Humans love to be by water:  They like to live and vacation by bodies of
water, they build pools and fountains in their yards and even in their
homes, they go to great expenses to have hot tubs, jacuzzis, and other pools
of water at hand.  
7.  "There is plenty of evidence that the oldest human settlements were at
the margins of water...."  Further, all original sites of civilization and
all great cities are situated on or near coastlines or water ways.

The fact that most fossils are found in savannah does not invalidate this
hypothesis nor prove that humans are native to grasslands, because a)
fossils are not well preserved in coastal areas, but are so in dry areas,
b) any fossils of past human occupation of coastal areas would be buried
under areas of continuous occupation, so it would be necessary to dig up all
of Paris, for example, to find the garbage heaps of prehistoric Parisians,
c) the coastline constantly changes, and tides would erode or wash out to
sea any artifacts. 

Crawford and Marsh maintain that inland dwelling and attempts to exploit the
savannahs came only after the choice real estate--waterfront property--in
any area reached its human carrying capacity.   So what we find in the
savannah artifact digs are the remains of people who were running a new
experiment, not living the original human way of life (which has continued
to this day, on the waterfront).  Similarly, modern H-Gs found living in
savannahs do not represent the original human way of life, but are only
found there because the choice property, the waterfront property, which
humans have always preferred, is occupied by modern man.  They are
exceptions to the rule, not the rule.

In essence, C& M ask: If the savannah is man's natural habitat, why aren't
we living there today?

That certainly means hunting the herbivores that
> thrive in the grasslands; no question about that.  We seem to be
> able to accept that these rather unimposing primates had the
> ingenuity to hunt, kill, and butcher animals, using simple stone
> tools.  Why is it so difficult to imagine that they also had the
> ingenuity to exploit the grasses themselves, by gathering,
> soaking, and/or parching grains?

Very good points.  Another point is made in Budiansky's book Covenant of the
Wild.  We imagine humans one day waking up and saying, "Well, today I think
I'll start domesticating grains,"  but in all likelihood, "domestication" is
simply a symbiotic relationship that developed over millenia of interaction
between human species and grass species.  Budiansky points to a similar
relationship between squirrels and oak trees, where the squirrels depend on
the oaks and the oaks depend on the squirrels.  Humans must have been
choosing out large grass seeds for many thousands of years, and spreading
those seeds one way or another, giving some grass species an advantage in
reproduction and protection, in order for "domestication" to have occurred.

Don