Re: Insulation does not = "Warm-blooded"

["David Marjanovic" <david.marjanovic@gmx.at>]

> However, I do have something to say about the following:
>
> > From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> > David Marjanovic
> > >I
> > > think that in popular imagination it does, but in reality a
> > bradymetabolism
> > > doesn't hinder any of the proposed lifestyles of dinosaurs, so
> > I don't see
> > why
> > > the stereotypical reptilian activity levels should ever come into
play.
> >
> > Why doesn't it hinder any of the proposed lifestyles of dinosaurs, such
as
> > migrating from Alberta to Alaska and back, galloping at 50 km/h, running
> > bipedally at even higher speeds, ... according to P&L even
> > growing to over 1
> > tonne in the first place?
>
> EEK!  The Gospel According to Bob! :-)

Okay, okay... _Proposed_, I wrote. Not "plausible", "probable", etc.... Of
course I can't claim at present that there's enough evidence for the
above... propositions!

> *Ectotherms incapable of growing over 1 tonne: Actually, this is an
> interesting situation.  Fully terrestrial unquestioned ectotherms DO seem
to
> be limited in size: critters like _Megalania_ or the big tortoises or
> pareiasaurs.  Some non-contraversial ectotherms do GREATLY exceed this
size,
> though: giant crocs, plesiosaurs, etc., but these are aquatic forms.  Does
> make one wonder, though, if the limiting factor might include mechanical
> support rather than physiology?

Well, P&L write that a certain physiology -- tachymetabolism -- is needed to
_provide_ the mechanical support for bulk greater than something like 1 t. I
still wonder, however, why there are no unquestioned ectotherms with erect
limbs -- and about the physiology of rauisuchians, and how their peculiar
stance evolved...

> As above, more work needs to be done.

Sure! Wouldn't it be sort of boring otherwise? :o)