Prehistoric Life Prehistoric Secrets in Stone The Earliest Fossils The Silurian Reef Trilobites Fish The Coal Forests Early Reptiles and Amphibians Sea Reptiles Flying Reptiles The Teeming Seas Hunting Dinosaurs Biggest Dinosaurs Two-Footed Plant Eaters Plated and Armoured Dinosaurs Horned Dinosaurs The Mammal Age Dawns Grassland Mammals The Ice Age	Choose a Page:Biggest DinosaursGoing For Length*Long Skulls*Going For HeightBoxlike SkullsUltrasaurusLate Forms of Plant EaterFootprints Long Skulls Diplodocus and its relatives had long heads with narrow peglike teeth.   Previous: Back Book: Prehistoric Life Section: Prehistoric Chapter: Biggest Dinosaurs