Pachycephalosauruses are normally peaceful herbivorous dinosaurs, but they grow much more violent during their mating season, when they fight one another to win over mates and warn away interlopers. They also defend themselves vehemently when potential predators stray too close to their herd. The pachycephalosaurus's skull has a distinctive dome-shaped crown surrounded by numerous blunt, bony horns. This feature, combined with the dinosaur's powerful, compact neck, allows it to make battering-ram-like charges capable of inflicting great damage.