Re: CROCODYLOMORPH ENDOTHERMY

["Nicholas J. Pharris" <pharrinj@PLU.edu>]

On Fri, 26 Jan 1996 Dinogeorge@aol.com wrote:

> In a message dated 96-01-26 21:45:59 EST, pharrinj@PLU.edu (Nicholas J.
> Pharris) writes:
> 
> >Point taken, but I don't believe that an ectothermic physiology could 
> >support such an active, erect animal.
> >
> >
> 
> There is also a breathing problem that an erect posture solves. A sprawling
> animal cannot breathe while it is moving fast (see the Cowen paper I
> mentioned in an earlier post). An elevated posture alleviates this problem,
> even in ectotherms.

Why, then, do all living ectotherms sprawl?

> Also, an animal's activity is governed more by the efficiency with which
> oxygen reaches its cells than by its body temperature. Fish are almost
> constantly on the move, yet are almost complete ectotherms. How do they
> manage this, if endothermy is necessary to sustain a high level of activity?

The *most* active fish (sharks, tuna, sailfish) have evolved some level 
of endothermy. :-)

Nick Pharris
Pacific Lutheran University
Tacoma, WA 98447
(206)535-8204
PharriNJ@PLU.edu

"If you can't convince them, confuse them." -- Harry S. Truman