horns, defense, and sexual selection

[gator@mail.utexas.edu (c. brochu)]

Another aspect of this debate is the broad diversity of horn and frill
shapes seen within Ceratopsia.  This parallels the diversity of horns and
antlers seen in modern hooved mammals.  If the horns were primarily for
defense, we would expect them all to look more or less alike.  If they were
used for sexual selection (mate recognition, intraspecific combat, etc.),
we would expect large differences between taxa - and this is what we see.

I am not arguing that ceratopsian horns could not be used for defense.
However, I think it likely that sexual selection was a more important
component in their evolutionary history than pressure from predators.


Just a thought from someone who actually works on animals who lack horns,
antlers, bells, and whistles altogether.



__________________
Christopher Brochu
Department of Geological Sciences
University of Texas at Austin
Austin, TX 78712
512-471-6088

gator@mail.utexas.edu