Ceratopsia is a group of herbivorous dinosaurs known for their distinctive frills and horns. They lived during the Late Cretaceous period and are characterized by their beaked mouths and varied body sizes. Some well-known members include Triceratops and Styracosaurus, which used their impressive features for defense and display. These dinosaurs primarily roamed what is now North America and parts of Asia. Ceratopsians were social animals, often found in groups, which may have helped them protect against predators. Their fossils provide valuable insights into the diversity and evolution of dinosaurs during their time.