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Re: Subject: Bird hibernation/torpor




On Sat, 22 Mar 1997, Ronald Orenstein wrote:

> Except that both emus and ostriches will nest on open bare ground without
> tall grass.

Yes. Evolution and adaptations are always more complex than anyone can
imagine.  The giraffe's neck is variously said to be "for" early spying of
preds, nipping leaves off tall trees, and for male/male contests.  It may
be that it is for all of these things in the same way that an arm is "for"
boxing, eating, etc., etc.  Laying still for an emu might be a water
conservation tactic _and_ a stealthy tactic.  And sub-species may show a
distribution between these.  For example, there may be in emus sub-species
which exploit desert vs,. grass.  The torpor trait helps both.  But then
ostriches don't go into torpor...

        I wonder if there is anything in birds in general and ratites 
in particular which makes them superior osmoregulators.  Their ability to
find a refugium in the desert might be dependent on this.  

        And then there is the question of whether feathers or hair are
better for desert wear.    They couldn't be equally good cou;ld they?
And to keep the flow of consciousness going...would it be better for a
desert dino to have feathers or scales?