Re: T-Rex a Scavenger?!? (fwd)

[Matthew Donald Celeskey <mc7b+@andrew.cmu.edu>]

>> With all due respect to Jack Horner:  If T-Rex and all other tyrannosaurids
>> were just big vultures, Why did Triceratops and Torosaurus, among others,
>> evolve such elaborate and formidible defensive weapons.  Did T-Rex see a
> 
>Well, I guess that to reconcile that inconsistency, you also have to be
>from the camp who believe that all those horns and spikes weren't for
>defense at all, but were merely "sexual advertising devices". I can 
>agree with that on some dino gewgaws, like the crests on Dilophosaurus,
>but I don't believe for a minute that the horns on the ceratopsians or
>the spikes on ankylosaurs and stegosaurs were not used for defense at
>all, but were purely sexual. One can achieve flambouyance a lot more
safely...

I was fortunate enough to see Jack Horner lecture last fall at the
Carnegie Museum here in Pittsburgh, and the question of ceratopsian
horns as defense came up.  He was firmly of the opinion that the horns
were more or less strictly for combat amongst each other (is
intraspecific the right term here?), pointing out that one's head was
probably the worst place one would want a defensive weapon - if a
Triceratops would be lucky enough to gore a Tyrannosaurus, it would then
face the problem of several tons of opponent causing stress on its neck,
either thrashing or collapsing.

I don't really want to take the "pure scavenger" side of the debate
(right now the "able predator" arguments make more sense to me) but I
thought since the topic came up I'd throw out Jack's defense.  

I'm not sure about his argument - don't deer and buffalo use their horns
as defense against wolves, as well as for rutting?  Anyone know anything
about horns used against significantly larger predators? (like maybe
antelope or gazelle versus big cats?)

More food for thought.
Matt.