A Pachycephalosaurus skeleton on display at the Royal Ontario Museum, Toronto.
  • Keith Schengili-Roberts/wikipedia.com Creative Commons License
  • A Pachycephalosaurus skeleton on display at the Royal Ontario Museum, Toronto.
Pachycephalosaurs are among my favorite dinosaurs, so I was delighted to hear a new study focuses on these "thick-headed lizards." I honestly didn't realize this was news but in all likelihood their crazy dome heads were used to head-butt one another like rams or bison.

I was under the impression that paleontologists were already reasonably confident on the issue, but a presentation at the Society of Vertebrate Paleontology's 72nd Annual Meeting revealed "some of the most direct evidence for this antagonistic behavior":

Peterson, a professor in the University of Wisconsin geology department, and his colleagues took CT scans of the skulls and compared the distribution of lesions to those on the skulls of birds, crocodilians, and mammals- particularly mammals with horns.

The investigations reveal that "larger domed pachycephalosaurs such as Pachycephalosaurus may have been head-butting like Dall sheep or head-shoving like bison, while smaller, high-domed taxa such as Stegoceras may have been flank-butting like mountain goats," Peterson said.

One time I had a dream I was riding a subway and some pachycephalosaurs were head-butting each other in the train car. (Most of my dreams with dinosaurs have them in urban environments.) Man I wish I was at the Society of Vertebrate Paleontology's 72nd Annual Meeting...