Re: this is a zoo

[Chris Nedin <cnedin@geology.adelaide.edu.au>]

Dave wrote:

>My thanks to those of you who responded with information about Carnotaurus
>and Tyrannosaur skin, especially Ralph Miller.  It is interesting to me
>that such large animals have such relatively small scales.  Although there
>is a lot of variation, it is generally true that larger species of snakes
>and lizards have relatively smaller scales.  The scales of these theropods,
>and apparently of hadrosaurs, are truly tiny in relation to their body
>size.  Presumably this is related to thermoregulation.  Not to open the
>ectothermy/endothermy can of worms, but I have heard the complaint from
>proponents of the former that dinosaurs have insufficient insulation.  The
>fact is, large animals dissipate heat so slowly they do not need insulation.

A slight correction here. It is true that large animals have a heat loss
problem, but only where the climate is equitable and warm.  Put an elephant
in the artic or sub-arctic and it would die of heat loss very quickly.  In
environments where the ambient temperature is low or widely variable, even
large animals need some extra assistance, hence the wooly mammoth, wooly
rino, etc.

The dinosaurs lived at a time when the climate was mostly equitable and
warm, hence no need for an external covering.

Chris

cnedin@geology.adelaide.edu.au                  nedin@ediacara.org
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Many say it was a mistake to come down from the trees, some say
the move out of the oceans was a bad idea. Me, I say the stiffening
of the notochord in the Cambrian was where it all went wrong,
it was all downhill from there.