Just as most dinosaurs are believed to be wild and mean, most are. Unlike the wild and ferocious Tyrannosaurus Rex, the Velociraptor, is a smaller, agile dinosaur. The Brontosaurus can be found with the bigger, more gentle dinosaurs. The Tyrannosaurus Rex, Velociraptor, and Brontosaurus differ greatly in their body structure, diet, and discovery. The Tyrannosaurus Rex was a very large dinosaur. Measuring 50 feet long, the Tyrannosaurus stood over 20 feet tall. The head of the Tyrannosaurus was five feet long and filled with large teeth t ....