The king of the dinosaurs, and certainly the most famous. Tyrannosaurus Rex has lived in the imaginations of children and adults for decades. Staring in many films, books and television shows, Tyrannosaurus was certainly a terrifying hunter.
For almost 90 years, T-Rex was the largest known predator to have ever walked on the Earth. It was not until Giganotosaurus was discovered in Argentina in the 1990s that T-Rex was beat by a larger discovered preditor.
Tyrannosaurus was one of the last dinosaurs to die out. Being a late Theropod, it had just two digits, or fingers, in its upper forearms; the early Theropods had four digits. As the Age of the Dinosaurs progressed, they slowly lost fingers to three and finally two. Their arms also became much smaller.
Tyrannosaurus' arms were so short that they were probably not very useful. Its huge head, which was about four and a half feet long, could have been used to swallow a human in one bite. In order to reduce the weight, Tyrannosaurus' head was full of holes, an adaptation seen in many dinosaurs.