Re: Ceratopsian frills (was bipedal lunges)

[Dann Pigdon <dannj@alphalink.com.au>]

Rob Meyerson wrote:
> 
> Usually, features located on the head (horns, antlers, etc) are used >against 
> the owners own species.  Features on the tail (quills, spikes, >etc.) are the 
> ones used against predators, to aid in an escape.  >Ceratopian horns are most 
> likely for intraspecies combat.

        Modern horned herbivores seem to back up this idea. Most of
them never even try to use their horns to ward off predators,
but prefer to try and out run them (antelopes, deer, giraffe...)
The horns are usually used either in shoving or wrestling matches
with others of their own species, or purely as display devices (the
oryx for example).
        Of course dinosaurs were not modern horned ungulates, so
modern examples may not serve as good examples. But the precedent
is there (with a bit of a temporal reversal that is).

> 
> >I fully agree that for intra
> >species fights, mating displays and such like, close quarters "horn
> >wrestling" is likely. The deer analogy here is quite apt.
> >However that cannot be their entire purpose, because then why would they
> >be pointed, and why have a shield behind them?
> 
> As I commented in another posting, the frill and horns developed 
> >independantly from each other.  In is in the more developed ceratopians 
> >that these two features combined into, what I call, a unison bluff >display 
> (waving the frill and horns about would be an effective >deterrant).  In the 
> protoceratopians and chasmosaurine ceratopians, the >frill is pretty pathetic 
> as a shield; the large fenestra in the frills >would seriously weaken their 
> defensive abilities.

        Yes, frills began as extensions for the chewing mechanisms.
But even the flimsiest of frills may be enough of a visual deterent
to prevent a large therapod from going for the back of the neck,
or at least delay the fatal bite for a few precious seconds to give
the ceratopsian a bit of a chance. A combination of display AND
physical functionality. Afterall, most bluffs have to have some
basis in fact. Baboons settle most of their disputes with themselves
and other animals by baring their teeth, but those teeth are
still dangerous should they have to be used.


-- 
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        Dann Pigdon
        Melbourne, Australia

        Dinosaur Reconstructions:
        http://www.geocities.com/capecanaveral/4459/
        Australian Dinosaurs:
        http://www.alphalink.com.au/~dannj
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