These Dinosaurs were named for the three horns on their skulls. These horns, and the large bony neck frill behind them, were probably used for defense. And Triceratops certainly had a lot to defend against-- these guys lived at the end of the Cretaceous, in about the same time and place that T. Rex and other very large, very powerful predators lived!
Aside from defense, the horns and neck frill may have served a purpose in during mating season. The neck may have even helped to regulate body heat!
Triceratops lived up until the very end of the Cretaceous, and died out along with all of the other Dinosaurs that were around for the K-T Extinction Event.
Status : Extinct. Lived 72-65 million years ago
Location : North America
Size : Length up to 30ft (9m), Weight up to 26,000lbs (12 tonnes)
Classification : Phylum : Chordata -- Order : †Ornithischia
Family : †Ceratopsidae -- Genus : †Triceratops
Image : Nobu Tamura , Minnesota Jones