Re: bipedal lunges

[Chris Campbell <sankarah@ou.edu>]

Rob Meyerson wrote:
> 
> Chris Campbell writes;
> >John Clavin (Digital) wrote:
> >> The only time I can see rising on the hind legs to be useful is in
> >> driving the horns into an opponent at the end of a charge, when momentum
> >> would likely force both protagonists to rise up.
> >
> >I think that's mainly how it would be used; wasn't that the original
> >argument?  I get the impression that they'd be operating in much the
> >same manner as bighorn sheep, only against opponents as opposed to
> >conspecifics.
> 
> I have to disagree with this one.  If _Triceratops_ charged each other 
> from a distance, the results would be fatal to one or both animals.  
> Think of jousting knights using a spear (I forget the actual term), a 
> shield, and that's it.  No body armor.  Things are even worse for the 
> other chasmosaurines, their frill is not much of a shield, and is pretty 
> vulnerable to damage (toss out the shield in this one).  Not a pretty 
> picture.

Please read what I wrote.  I said against opponents as opposed to
conspecifics; perhaps I should have used the term 'predators' instead,
but in any event I thought I made it clear these animals weren't
fighting amongst themselves.
 
> I suggest that when these animals did fight, they did so at close 
> quarters, locking their horns and attepting to push their rival into 
> submission (think of deer for a moment).

I think this particularly likely with the short-frills, who mainly stuck
with nose horns (_Triceratops_ being the logical exception).  In the
long-frills it's much tougher to envision, as the act of locking the
horns would be much more difficult; slippage would be a big problem. 
However, after looking at the various skulls more closely I can't see
any other use for them; only _Torosaurus_ appears to have the length the
horns would need for use as weapons, and I'm beginning to think that
such use would be secondary at best.

But, then, there's _Triceratops_, whose horns would be pretty much
perfect as weapons and very, very bad in locks or jousts.  Perhaps the
horns had significantly different functions depending on the species?
 
> Also, the semi-erect to fully sprawling posture that these animals 
> had would provide extra leverege and stability during these confrontations.
> 
> For more info, see:
> 
> Farlow, J. O., Dodson, P.  1975.  "The behavioral significance of
> frill and horn morphology in ceratopsian dinosaurs."  Evolution.  29: 353-361.

Thanks for the cite; I'll look into it.

Chris