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Re: no easy (mammal) answer



> I suppose the smallest dinosaurs were about the size of chickens or
> human babies.  Babies are capable of incredibly high metabolism.  A hen
> has enough metabolism to survive a freezing, windy night even when
> molting leaves skin exposed.  In such a situation, a smaller bird would
> probably perish.

     Baby mammals and cold acclimated mammals have one edge over
endothermic birds in this regard; Brown adipose tissue or "brown fat" is a
tissue present in the above mentioned mammals but absent in birds, whose
apparant only function is to provide heat.  I know it has been suggested
that brown fat may have given mammals some kind of edge over birds after
the K-T extinction.  I am surprised that it hasn't been brought up
in these threads before.  

LN Jeff
O-
"Of all my imaginary friends, I don't think there is one I eventually
didn't have to kill."