[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Colored skin



spn3877@sae.ssu.umd.edu (Shannon):

>I am interested in hearing ANYONES idea about the color of dinosaurs
>skin.  I'm terribly interested in the sexual selection of dinosaurs
>but its difficult to research.

This is a good example of the kind of questions I think we'd all
like to see - some background, some indication of prior work, and
well-focused.

There are a couple arguments for color either way - if we presume
birds are evolved from dinosaurs, the colorfulness of birds argues
for color in the past - and color provides camouflage.  However,
some arguments go back the other way: larger animals today are
seldom anything but gray - elephants and rhinos don't _need_ camo,
and they themselves don't have full-color vision, so it is useless
for signalling each other.

Here is an interesting ramification of the t-rex-as-scavenger theory.
If we presume 'rex was an active hunter, then even a large dinosaur
would have a use for camo, and would have patterns of color to break
it up against the background and make it blend in.  If we presume they
were not directly predated on, that 'rex was strictly or nearly strictly
a scavenger, they'd have no such need, and would likely therefore be
just gray.  Choose your choice.

I suspect they had some color and patterning - not bright, necessarily,
but serving to camouflage them against the background.  If, however,
they had color vision, as birds do, then color might have been heavily
involved in sexual displays - they might have had flashy, colorful
crests, bright displays on back or chest or face, and otherwise be
similar to our modern birds in terms of color use.  Sadly, we can't
yet prove this either way.  If we were to find a mummified eye that
would let us guess at the rods-vs-cones ratio, it would tell us some-
thing, but for now, color is much the province of the theories you
believe in.  Incidently, this observation works both ways - if we
can prove they were colorful, it argues for color vision.

By the way, there is one ichthyosaur - ophtho-something - that I
recall did leave us a fossilized piece of skin that let us guess
at the color very accurately.  But, I saw that in Time Frame, the
dinosaur "photography" book that baldly asserted that t-rex _was_
a scavenger with no hint that this is controversial, so perhaps
we should take it whence it comes.  Any comment from the pro-
fessionals?

regards,
Larry Smith