Tyrannosaurus (pronounced /tɨˌrænɵˈsɔrəs/ or /taɪˌrænɵˈsɔrəs/, meaning 'tyrant lizard') was a genus of theropod dinosaur. The species Tyrannosaurus rex ('rex' meaning 'king' in Latin), commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other tyrannosaurids. Fossils are found in a variety of rock formations dating to the last three million years of the Cretaceous Period, approximately 68 to 65 million years ago. It was among the last non-avian dinosaurs to exist prior to the Cretaceous–Tertiary extinction event.
Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to the large and powerful hindlimbs, Tyrannosaurus forelimbs were small, though unusually powerful for their size, and bore two clawed digits. Although other theropods rivaled or exceeded Tyrannosaurus rex in size, it was the largest known tyrannosaurid and one of the largest known land predators, measuring up to 13 metres (43 ft) in length,[1] up to 4 metres (13 ft) tall at the hips,[2] and up to 6.8 metric tons (7.5 short tons) in weight.[3] By far the largest carnivore in its environment, Tyrannosaurus rex may have been an apex predator, preying upon hadrosaurs and ceratopsians, although some experts have suggested it was primarily a scavenger. The debate over Tyrannosaurus as apex predator or scavenger is among the longest running debates in paleontology.