Labels:text | font | screenshot OCR: Pachycephalosaurs ("thick-headed" dinosaurs), were a group of dinosaurs that had a domed or flat skull topped with a thick layer of bone. Pachycephalosaurs belonged to the marginocephalians ("margined heads"), a group of "bird-hipped" dinosaurs with a skull ridge or shelf. Male pachycephalosaurs were once thought to have had head-butting bouts when competing for females or territory, just like mountain goats do today. Supposedly they ran at each other headfirst, clashing heads together to fight for dominance. The thick bone of the "crash helmet" skull seemed evidence for this type of behavior. New research shows that this bone was not very strong. Perhaps rival males butted each other's flanks instead.
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