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

Re: Dino coloration and more...

Jeffrey Martz wrote:
>David Portee wrote...
>> Also, I'm interested in talking to folks about what
>> this might mean for the coloration of theropods. Specifically, does
>> Sinosauropteryx lend credence to the widespread notion that they might've
>> been brightly colored like modern birds (for example, toucans and cardinals)?
>> Anyone interested?
>     Sure, but not necessarily any more likely then that scaled theropods 
>were brightly colored.  There are brightly colored and dull modern birds, 
>and brightly colored and dull modern reptiles.  

As a newbie to this list, and not a professional paleo-anything, I'm
ready to accept any slings and arrows that might be hurled my
way. Still, I have a couple comments to add to some threads I've seen

        As far as coloration, whether feathered or scaled: It seems to
me that coloration depends a lot on one's position in the food chain,
one's environment, and whether one's primary predators or prey are
color-sighted or color-blind. Prey animals gain from camouflage by
being harder for predators to see. Predators benefit by being able to
approach closer to prey. Animals whose primary predators are
colorblind (e.g., zebras) may sport a camouflage scheme that's highly
visible to color-sighted animals (e.g., us).
        Highly visible animals occur in two situations: where the
environment is similarly colored (rain forest butterflies and birds),
and where there is no need of camouflage or stealth (skunks, poison
        What about display coloration? Lots of display "flash" is
temporary, either momentary or seasonal. In other cases, the benefits
of looking sexy obviously outweigh the danger of the added visibility
-- or they'd be extinct.
        What does this mean to dinos? Depends on whether you accept
them as color-sighted. (I don't know about the experts, but I'm ready
to.) Birds live in a world of color, and some are very colorful --
given the survival pressures mentioned above.  I'd expect at least
some dinos to be brightly colored, but most to have camouflage
coloration. It's interesting to note that very few predators have
high-visibility color schemes -- the coral snake is the first that
comes to mind, and that's defensive. Finally, since flowering plants
didn't show up until the Cretaceous, I'd expect most creatures to be
more in the drab shades until then.

In other things: the whole "kicking predators" business started when
Brian Franczak wrote:

>will give you an idea of how difficult it would be for that animal
>to keep an eye on a predator attacking from behind. The rear is not
>the best place for armament, and stegosaur tail spikes were probably
>used for other behavior than defense, possibly display or courtship.

And Rob Meyerson said:

>An animal doesn't necessarily have to keep an eye on a predator to
>get in a good hit...

Any of you guys ever try to sneak up on a horse? Rob's kicking zebra
doesn't have to turn around and look, because they have a field of
vision of almost 360 degrees. Most grazing animals have eyes placed
tangentially on the sides of their heads, creating very wide visual
fields. Granted, the body of an ankylosaur looks like it would make a
big hole in its own field of vision, and possibly stegos too, but then
they could at least guess that the predator they smelled was where
they couldn't see them -- behind.  This doesn't need to be thought,
just a hard-wired instinct.

Finally, this just came in from Stephen Throop as I was writing this:

>...Here's another puzzle.  It seems that all flying dinosaurs had long,
>heavy tails.  Modern land animals carry only little tails, and birds use
>feathers for tails.  How could a dinosaur have flown with all that
>weight?  It's even harder to understand why something as unsuited to
>flight as a big tail didn't soon evolve to a little tail.  Instead, it
>seems that flying dinosaurs kept their big tails for millions of years,
>until they became extinct.

While I won't approach the problems of mass and wing vibration that he
mentions in other parts of his posting, I seem to recall that many of
the big "flying dinosaurs", which I always though of as "pterosaurs",
had no tails, or very short ones -- Pteranodon and Quetzalcoatlus
spring immediately to mind. The little pterosaurs (rhamphoryncus,
dimorphodon) got away with relatively big tails, but I don't recall
any big ones having much tail to speak of...

I'll stop here and see what response this brings.

Wayne Anderson