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Re: Theory of Non-Avian Dino Extinction

On Tue, 18 Mar 1997, Bettyc wrote:

> Matt Fraser wrote:
> > Are there any extant species of reptile or, more to the point, bird that
> > truly hibernate? Seems to me that if you could find such a critter, you
> > would have an "in" for dino-hibernation.
> Rattlesnakes hybernate.  Turtles hybernate.  Some lizards. Can't think
> of any birds that do.

OK. So we have reptiles, but no birds (I also have never heard of
hibernation in birds, and I think (hope) that I would have remembered
that one). I guess that now the question is are snakes, turtles and
lizards, poikilotherms, good models for homeothermic Dinos?  If there are
no extant birds that hibernate, and we accept the Dino-Avian close relationship,
then it seems somewhat unlikely, although certainly not impossible, for
Dinos to have been hibernators.  

Now against this argument are the homeothermic mammalian hibernators.
They are homeothermic and dinos were presumably homeothermic.  So, why
not?  Perhaps if we found out why birds don't, it might give us some
insight into whether Dinos did. Birds range throughout the world and
would certainly have had the opportunity to "be" hibernators, but
instead go to great lengths in order to migrate. These migration routes
have been lengthened in many cases by continental drift (no doubt to the
chagrin of the birds). If they could hibernate, it might save them a lot
of energy.  Perhaps dinos were not as good at terrestrial "migration" as
the flyers, and when the need arose either to migrate at all or for
greater distances, they couldn't make the trip. There may be some
important difference in the thermoregulatory mechanisms that
might prevent birds (and dinos) from being hibernators. Something to do
with differences in the physiology of metabollic rate homeostasis between 
mammals and birds/dinos, perhaps.

Interesting question.



                     Member of The Paleo Ring


Matt Fraser                               "The Real World is very 
                                            complex and chaotic,
mattf+@pitt.edu                         so that, in order to survive,
                                   humans find it necessary to construct   
                                           an illusion of reality."
                                               Author Unknown