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Re: Warm and Cold Bloodedness

>For a long time I have accepted the premise that prolonged physical exertion
>is possible only for warm-blooded animals, but I have never understood the
>reason why this ought to be true.  If the advantage lies in the muscles being
>warm and better able to move, then I would think that warm bloodedness would
>be most beneficial for short bursts of speed because the muscles would already
>be warm.  This would be irrelevent for prolonged activity because the muscles
>would warm themselves.  There must be something beyond the temperature itself
>that supports the assertion, but I don't have any idea what it is.
>Bart Singer

I'm not a physiologist, but from observations of reptiles I wouldn't say
that "prolonged activity" IS gained from endothermic muscle. Anacondas and
crocodiles wrestling with mammalian prey don't seem to "tire out" that much
quicker, if at all, than lions or tigers.

 Endotherms do seem to have the advantage of quicker recovery rates after
periods of exertion.  I'm fairly certain someone has worked on this subject,
but for the life of me, I can't remember who.


Thomas R. HOLTZ
Vertebrate Paleontologist, Dept. of Geology
Email:Thomas_R_HOLTZ@umail.umd.edu (th81)