Pachycephalosaurus head-butting

[Seijun]

http://news.discovery.com/animals/dome-headed-dinosaurs-121017.html

I thought the most recent consensus was that pachy's most likely used their domed heads to ward off predators, or for display, not for head-to-head fights with each other?

[SBell]

http://news.discovery.com/animals/dome-headed-dinosaurs-121017.html

I thought the most recent consensus was that pachy's most likely used their domed heads to ward off predators, or for display, not for head-to-head fights with each other?

It's rarely ever consensus--more like, there have been some more recent studies suggesting other purposes recently.  And yet, here we are with evidence that they were hitting something. Not really surprising--if they were just display, why bother filling them with (metabolically) expensive bone, when a big hollow chamber could suffice? Although display would likely still be part of it--a large dome might mean an older, experienced individual that shouldn't be messed with.

[Gryphoceratops]

I think for a long time people imagined two pachies taking a running start and banging their heads together which was then deemed unlikely.  However I think its def likely that they were still smashing each other with them, just maybe in the gut or the flank, perhaps in the head just at a closer distance.  Check out modern headbutters. 

http://www.youtube.com/watch?v=SNJgdAOyMQE

See how more than half of it is sparring at close quarters? 

Or if you would rather have another reptile example here is a vid with display and combat. 

http://www.youtube.com/watch?v=Fc13IcHwERs

I'm sure they wouldn't hesitate to smash a predator as well. 

[stoneage]

http://www.bioone.org/doi/abs/10.1666/0094-8373%282004%29030%3C0253%3ACHOPOM%3E2.0.CO%3B2

[SBell]

http://www.bioone.org/doi/abs/10.1666/0094-8373%282004%29030%3C0253%3ACHOPOM%3E2.0.CO%3B2

So we have one group saying showing structures inconsistent with head-butting, and one showing structures consistent with head-butting...

They'll figure this out eventually I'm sure.

But one thing to point out--who is involved with the 'contrary to conventional thought' paper...? Not that this negates anything, but it seems to be something to be aware of.

[Seijun]

Could it be that head-butting was a behavior only younger animals engaged in? Although, the thing I find hardest to believe about pachy head butting is that the dome shape is really not ideal for that behavior. Imagine hitting two dome-shaped stones together, one will inevitably want to "slip" to the side. Modern head-butting animals don't have this issue because they have horns and antlers that help create a flattened surface area or that lock with the antlers and horns of the opponent.

[Gwangi]

Could it be that head-butting was a behavior only younger animals engaged in? Although, the thing I find hardest to believe about pachy head butting is that the dome shape is really not ideal for that behavior. Imagine hitting two dome-shaped stones together, one will inevitably want to "slip" to the side. Modern head-butting animals don't have this issue because they have horns and antlers that help create a flattened surface area or that lock with the antlers and horns of the opponent.

I was thinking about that myself and I believe that is one of the arguments used by those against the head butting theory. Perhaps part of their ritual simply involved pressing their heads together and whoever deflected first would be the loser? I'm just speculating but maybe their heads were designed the way they were because the head butting activity was not what we would normally assume it to be.

[Gryphoceratops]

Could it be that head-butting was a behavior only younger animals engaged in? Although, the thing I find hardest to believe about pachy head butting is that the dome shape is really not ideal for that behavior. Imagine hitting two dome-shaped stones together, one will inevitably want to "slip" to the side. Modern head-butting animals don't have this issue because they have horns and antlers that help create a flattened surface area or that lock with the antlers and horns of the opponent.

Like I said its very possible these guys were butting heads at a much closer range than most people thought where there wouldn't really be much slipping around regardless of shape.  They could have even been stationary, standing very close and tussling around using their thick heads to shove and prod.  I don't know specifically how (nobody does) but what I AM fairly confident about is that those domes were used for some sort of combat within the species.  Adaptations like that very rarely are evolved for anything else. 

Also if anyone is interested the actual paper is here.  Its not terribly long. 

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036227

[Yutyrannus]

I'm glad that there is more evidence for head-butting in pachycephalosaurs. I was always a supporter of the head-butting theory. Also now I have more evidence for my upcoming "Head-butting Stegoceras" drawing .

[s.foulkes]

Well here is what i have learned as of most recent and it sound plausible to me. The pachy's did NOT have the proper stucture of cervical Vertibrea to withstand direct inline head butting even thought however the top of the heads are rounded so at least the impact would be a glancing one. More over there necks had a slight "S" curve to them so the famous straight neck inline with the head thing is out of the question. Now what may have happened is that they tossed there spike studded dome sideways at close quarters ,sort of like Giraffes do today, but not head to head but head to body, this might explain the very robust and infalted rib cage ,thus protecting the inner organs. WOuld be nice to study the ribs of these Dinos to look for pathologies.