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Re: Sauropods and those little heads

In a message dated 97-06-27 09:49:41 EDT, tons@ccs.netside.com (Michael)

> I suspect that you and George are right.  The correct term is 
>  heterothermy though.  Endotherms keep their body temperature in a 
>  small range.  Heterotherms have a much larger range.  

One more time.

Endotherms generate heat internally.
Ectotherms rely on heat from outside sources.
Heterotherms are endotherms sometimes and sometimes allow their body temps to
     drop to (or near) ambient levels.
Homeotherms keep their body temperatures relatively constant.
Poikilotherms have body temperatures that fluctuate more widely.
Tachymetabolic organisms have high basal metabolic rates.
Bradymetabolic organisms have low basal metabolic rates.

And of course there are levels in between the extremes listed here.  Great
white sharks and tuna, for instance, are partial endotherms.  Monotremes and
some lipotyphlans have much higher metabolic rates than lizards but somewhat
lower than other mammals.

What you are proposing here, if I understand you, is that sauropods were
bradymetabolic (slow metabolism) endotherms (heat from inside) that were
mildly poikilothermic (temps fluctuated somewhat).

And I continue to see little compelling reason to believe that all dinosaurs
were not tachymetabolic, endothermic homeotherms.  Nevertheless, I concede
that we will never know for sure (at least until someone figures out a
feasible mechanism for time travel).

Which reminds me, if you're going to build a time machine, it had better have
space travel capacity as well, since the earth will be quite a distance from
where you left it.   (No one seems to have considered this problem before, so
I just thought I'd mention it!)

Nick P.