With vicious and violent beasts such as Tyrannosaurus rex on the loose, the odds of a peaceful herbivore surviving an encounter with a carnivorous dinosaur seem long. However, plant-eating dinosaurs had plenty of defenses to help them battle such brutes. Pachycephalosaurids had especially thick bones to head-butt their enemies. Stegosauruses had plates and spikes to deter carnivores. Other dinosaurs, such as Ankylosaurs, had tough, plated bodies,...