Interestingly, while
Pachycephalosaurus is described as a plant-eater in most media, some paleontologists have suggested that it and its relatives were omnivores. The teeth of the LBT pachys
are much larger and sharper than those of the real dinosaur, but if you look at a pachycephalosaur skull (
http://www.flickr.com/photos/tomw1942/2311035794/), you will see that this wasn’t exactly a dinosaur you would call a “flattooth.” (There’s no scientific basis for the ghoulish claws of the LBT domeheads, though.) The teeth in the front of pachycephalosaur jaws were pointed and conical (good for nipping), while those in the back were small and serrated, better suited for shredding than chewing. Interestingly, the theropod
Troodonóa dinosaur generally regarded as a meat-eaterówas once believed to have been a pachycephalosaur, because its teeth were so similarly shaped; it too may have been omnivorous.
I’m willing to attribute the aggressive behavior of the LBT pachys to territoriality (the two in movie IV certainly seemed to show more interest in attacking each other than the gang), but I wouldn’t put it past the pachys in the first movie to have been intent on eating Cera. Perhaps such an opportunistic diet is what enables the domeheads to survive in regions forsaken by most other dinosaurs, such as the Burning Mountains and the Land of Mists. Consider that the egg stealers and fast runnersóboth omnivorous dinosaursóare seen to do reasonably well in regions that the Great Valley residents consider inhospitable.
As for the domeheads we have seen in the Great Valley (in movies V, VI, XI, and XII, as well as numerous TV episodes), I would imagine that the abundance of green food there removes the necessity for such territorial and part-time predatory behavior, allowing them the same “culturized” lifestyle as the other leafeaters. As an off-note, I suspect that the adolescent domeheads in the TV series are a different species (possibly
Stegoceras or
Prenocephale) than the other domeheads we have seen, given their radically different coloration and the fact that they lack nose horns (even the baby
Pachycephalosaurus from movies VI and XII had those).