Pachycephalosaurs

[Ralph Chapman <MNHAD002@SIVM.SI.EDU>]

 I believe John is right. Those who have argued vehemently against head
 butting in pachys tend to visualize a very end-member version of it -
 two majestic beasts starting out a 1/4 mile apart and running head long
 into each other, etc. You can head butt from a few inches away and get your
 point across and not worry about "dangerous glancing blows", etc. That
 especially goes for Pachycephalosaurus with the flatter dome (relatively
 shaped) but should work for most. That does not preclude flank attacks
 or other uses as well but I found found all arguments I've heard against
 head-butting non-impressive for less drastic head-butting (maybe we
 won't put pachy's on Bock Beer labels - or maybe we will...). Perhaps
 Ken Carpenter will favor us with a reiteration of his arguments and let
 me know I'm full of balloon juice (won't be the first time, but we do it
 in a friendly way). I recall Padian making arguments against it at the
 Dino Systematics Symposium back in the Pleistocene but recall his arguments
 would also fit Mountain Sheep which, of course, do head-butt (I've seen
 pictures!). Perhaps Kevin will reiterate those here as well so I can
 see just how bad my recollection of those old days is.

 Anyway, for a moderate form of close-in head butting I think pachys
 would do just fine and did some. How about predator-defense? I think
 that the dome fits the sexual model better - that's why they have the
 best documented sexual dimorphism in the dinos - but certainly if a
 theropod is about to eat you I'd do anything I could. Saw movies of an
 elk fighting a grizzly with its big rack for defense. Was pretty impressive
 as a defensive stand - didn't work but the elk had guts - and then we saw
 them.

 That's my nickle's worth, let the games begin.

 Ralph Chapman, NMNH