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Re: Hot-blooded dinos



> (the crocodiles are capables of gallop!),

Nino came out with this in part od his post on hot-blooded dinosaurs but it
has occurred elsewhere. I just wanted to put in my five cents worth on this
issue.

One species of crocodile (Crocodylus johnstoni, the Australian Freshwater
Crocodile) has been seen to gallop but only under the most exceptional
circumstances. There is a famous set of photos of a freshie bounding across
a sandbank. What the photo doesn't show is a group of field technician
making an almighty din behind it and the technician holding its tail until
it was really, really scared.

Although my expericence with live freshies is limited, I have never seen
one gallop. And my experience with freshies includes a number of raptures
and releases of animals up to 2'6'' long (bigger than that and they are too
dangerous for a whimp like me!). Many of these releases have been on land
including on incident when we tried to get a freshie to gallop (it just ran
off rather quickly, but definately not a gallop).

So while a few, exceptional observations have recorded one species of
crocodile galloping, this only demonstrates that one typeof croc can do so
(and a fater derived species at that). We should be extremely wary of
apparently including galloping within the normal repetoir of movements for
all crocodilians.


>-Pole-to-Pole: yes, the dinos lived in the polar zones, where at least the wint
>er had  freezing temperatures. This is one of the most solid arguments favourin
>g the hot-blooded theory

Becareful about using this type of logic in defence of homeothermy. For
example, one of the "near Polar" dinosaur faunas from southern Victoria
includes a labyrinthodont. So unless you wans to claim labyrinthodont
endothermy, it is more likely that paleo-polar climates were substancially
different from modern polar climates and could probably support large
ectotherms.

Over all I agree, homeothermic dinosaur does sound good and make sence, but
it is not sealed and delivered and requires careful analysis of the data.

Cheers, Paul

pwillis@ozemail.com.au

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