Pachyrhinosaurus

Pachyrhinosaurus is a member of the ceratopsian family. Like all horned dinosaurs, it fed on plants and it used its head to protect itself or it's young from predators such as tyrannosaurs and also raptors like Troodon and Gorgosaurus. But unlike its relatives, it had no horn so instead it had a bumpy formation on its skull so we think that Pachyrhinosaurus used its head to ram its enemy or against other males to earn females during mating seasons.