Re: Insulation does not = "Warm-blooded"

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

> I believe that L.C. endothermy didn't show up in birds until the
> enantiornithines (i.e. it probably showed up in some enantiornithines). I
> don't think all enantiornithines were L.C. endotherms though. Of course
since
> enantiornithines were the sister group to neornithines it doesn't help
much
> with extant avians. I do think all Neornithines were L.C. endotherms, but
I
> don't know enough about them to say much more. I will say, though, that I
> don't believe that archaeopteryigiformes like _Archaeopteryx_ and
_Rahonavis_
> were L.C. endotherms. Everything after them gets confusing.

You believe, you think... why?

> > Does bradymetabolism imply low rates of
> > activity, stereotypically "reptilian" activity levels (notice I said
> > "stereotypically")?
>
> You mean like sprawling, swamp dwelling sauropods and scavenging
theropods? 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?