If you had to guess, how many types of dinosaurs do you know? I bet there are even a few that you didn’t know existed! Dinosaurs roamed the earth before the existence of mankind. Even though it's been millions of years since dinos have walked the earth, these prehistoric giants are famous today. Many have a favorite dinosaur already, but let's see if that changes after this list! 1. Tyrannosaurus Rex (T.Rex) The T.rex was known as a theropod and to no surprise, is the most famous dinosaur. The name tyrannosaurus means 'tyrant lizard king,' which is very fitting for this 40-foot carnivore. The largest tooth on any carnivorous dinosaur is estimated to be 12 inches long, not including the root. The popular dinosaur is said to have loved chasing its prey and using its small arms and powerful jaws to devour its meal. 2. Stegosaurus The stegosaurus was an easily identifiable 30-foot Ornithischian dino. Distinctive plates ran down the back of the dinosaur that may have been used as a means of defense against predators or helped level out their body temp. Even their tail had spikes that were worn and damaged, suggesting it was used in combat. 3. Triceratops The triceratops was a 30-foot plant-eating dino that lived in North America. It's one of the most famous dinosaurs and its three horns make it most recognizable (the snout, and the other two at the top of its face). The horns and shield may have been a defense mechanism against predators or used to establish dominance against other Triceratops. 4. Velociraptor Not the biggest dino at 6.5 feet long and 1.6 feet tall, but their claws were killer (literally). The Velociraptor was a great hunter that had both feathers and wings. A famous fossil showed a Velociraptor fighting a Protoceratops. 5. Diplodocus Unlike the Velociraptor being small the Diplodocus was as long as a city bus! Although they were big in size, Diplodocus were herbivores, feeding on leaves and other greenery. Researchers suggest they were around 10-15 tons in weight, and their tails contained around 80 vertebrae. While these 5 are the most popular, many dinosaurs roamed Earth. Check out the list below for another 10 of the most popular dinos that walked the Earth. Popular Dinos Spinosaurus Brontosaurus Ankylosaurus Archaeopteryx Iguanodon Brachiosaurus Parasaurolophus Allosaurus Gallimimus Giganotosaurus