Tyrannosaurus

Tyrannosaurus (name meaning "tyrant lizard" ) is a genus of theropod dinosaur which lived during the late Cretaceous period. It lived in North America at the time the continent was an island termed Laramidia. Tyrannosaurus lived during the Maastrichtian age of the late Cretaceous period. It was one of the last non-avian theropods to exist before the Cretaceous - Paleogene extinction event. Commonly abbreviated T. rex, Tyrannosaurus is the most iconic dinosaur in popular culture and in literature.

Although other theropods rivalled or exceeded it in size, Tyrannosaurus was the largest known tyrannosaurid and was one of the largest land predators, with the largest complete specimen measuring up to 12.3 metres in length and up to 4 metres tall at the hips. Like other theropod dinosaurs, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, stiff tail. It had very strong hindlimbs but had very small, two-clawed forelimbs. Small as they were, they were actually quite powerful. Tyrannosaurus was a heavily built animal, with the largest and most complete individuals weighing up to 6.8 metric tons.

Being the largest carnivore in its region, Tyrannosaurus was most certainly an apex predator, preying on hadrosaurs, ceratopsians and possibly even sauropods, though some scientists argue that Tyrannosaurus was primarily a scavenger. The debate is ongoing but most scientists agree that Tyrannosaurus was an opportunistic carnivore, both predating and scavenger.

Description
Tyrannosaurus rex was one of the largest land carnivores ever to live; the largest complete specimen, FMNH PR2081 ("Sue") being 12.3 metres (40 ft) in length  and 4 metres (13 ft) tall at the hips. Estimates of Tyrannosaurus' weight range from as high as 7.2 metric tons to as low as 4.5 metric tons but modern estimates range from 5.4 metric tons to 6.8 metric tons.