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 Dinosaurs*Going For Length*Long SkullsGoing For HeightBoxlike SkullsUltrasaurusLate Forms of Plant EaterFootprints Going For Length Diplodocus was 26.8 metres long. Spines at the hips supported muscles that allowed it to rear up on its hind legs.   Previous: Back Book: Prehistoric Life Section: Prehistoric Chapter: Biggest Dinosaurs