Re: Cursorial adaptations (was T.rex and elephants)

[Jonathon Woolf <jwoolf@erinet.com>]

Chris Campbell wrote:

<large snip> 

> This doesn't argue for the wrestling scenario you give below, though;
> perhaps the individual in question just pissed off an adult while it was
> a juvenile, eh?  Alternately, the short-frilled ceratopsians (with
> short, bony frills) might have done the head-butting thing while the
> long-frills (having holes in 'em) didn't.

Could this be the evolutionary _reason_ for the long-frills?  As best I
recall, short-frills came first and long-frills later.  Long-frills also
have the openings in locations that make them look sort of like
eye-holes in a mask.  In THE HORNED DINOSAURS, Peter Dodson sketches
complete _Triceratops_ heads and frills with a multicolor scheme that
places mock-eyes on the skin over the holes, so that when the head drops
and the whole frill is facing forward, it looks like a very large face.  

So maybe we could reasonably envision a scenario something like this:
Short-frills spar with horns at mating time -- an active method of
settling conflicts.  Because of the potential for serious injury to both
parties, this isn't a very good method of settling disputes.  So, over
time the long-frills develop so that the active conflict can be replaced
by less direct passive conflicts of displays.  Whoever has the most
impressive display wins.  Only in two very well matched individuals
would the old method of active combat come into play.

-- Jon W.