Pachyrhinosaurus was a large herbivorous dinosaur that lived during the late Cretaceous period, around 70 million years ago. It belonged to the group of dinosaurs known as ceratopsians, which are characterized by their frills and horns. Unlike its relatives, Pachyrhinosaurus had a thick, bony boss on its nose instead of prominent horns. This dinosaur was primarily found in what is now North America, particularly in areas that are part of Alberta and Montana. Pachyrhinosaurus could grow up to 20 feet long and was likely a social animal, living in herds for protection against predators. Its unique features suggest it may have used its head for display and social interactions.