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