Pachycephalosaurs, head butt no more!

A histological and ontological study of fossil skulls of pachycephalosaurs published by Mark Goodwin and John Horner in the latest Journal of Paleobiology, refute the long held idea that the thick boney skulls were used as battering rams; a behavior found in living bighorn sheep. Their findings show that as the pachycephalosaur's skull matures the bony structure of the frontoparietal changes. Only in the youngest individuals is the radiating structures of the outer third zone found, which have previously been cited as evidence of head-butting behavior. Older individuals have "softer" skulls, with a thinner outer layer of bone.