Denis :
> HOwever, I would point out that studies on adaptation
>physiology concur in saying that  a small stature is an advantage when
>living in the tropical/equatorial zone.

 Following previous exchange on the subject (Tu-Peyrat) herewith an outline
of  ideas extracted from  an article by H.Walter "Remarks on the
environmental adaptation of man" from Humangenetik 13, 85-97 - 1971

1) Body size  and body weight show distinct and specific geographical
distribution patterns with more or less evident relations to food supply and
climatic conditions.
2) Average body size increases from warmer towards cooler biotops, which
conforms to Bergmann's rule  "within polytypic warm blooded species,  the
body size of a subspecies increses witgh decreasing temperature of its biotop."
3) Bigger size bodies are generally considered as having an advantage for
tackling  big game except in dense  forests.
4) Large body size is disadvantageous in areas with little food supply.
Genetically large children are at a disadvantage  because they require more
calories to survive. Small body size however cannot be considered as the
result of adaptive selection to insufficient food supply (no protein
deficiency amongst pygmies)
5) Body size may play some role in connection with the heat regulation of
the human organism. Other factors likely to be involved are body weight and
surface.
6) There has been found a marked relationship between the mean body weight
of more than 100 populations from various part of the world and the mean
annaul temperature : the higher the mean annual temperature , the lower the
body weight tends to be.


Discussion :

The author of the article confirms my earlier post (above) and therefore
invalidates Jean Louis' reasoning (which I could not find and repost here ).
The loss of heat of an organism is proportional to its surface and the
production of heat is proportional to its mass (which, from memory, is
exactly what Jean Louis said). However Jean Louis must have made the wrong
hypothesis that the surface of the body is proportional to the height. On
the contrary,  Schreider found that populations of tropical biotopes ,
despite their smaller stature (see 2) above) are generally characterised  by
greater surfaces as compared to those of non-tropical areas.
Therefore smaller inhabitants of tropical areas clearly show a higher
surface/mass ratio as compared to bigger organisms. They produce less heat
and they cool off more quickly than populations from temperate areas .

Another article by the same author "Korperbauform und Klima" in
Z.Morph.Anthrop. Bd 67 241-1-263 1976 shows on a world map the variations of
average body size according to the various populations. With over 175,1 cm
average size, the MAsai are unique in the whole African continent and indeed
throughout the world ( only Scandinavians can match their size ). What a
coincidence : they both share an inveterate taste for sucking at their
cows' udder...

Cheers
Denis