To compensate for the immense bulk of the animal, many bones throughout the skeleton were hollow, reducing its weight without significant loss of strength.Large fenestrae (openings) in the skull reduced weight and provided areas for muscle attachment, as in all carnivorous theropods.As the archetypal theropod, Tyrannosaurus is one of the best-known dinosaurs since the 20th century, and has been featured in film, advertising, and postal stamps, as well as many other types of media.Tyrannosaurus rex was one of the largest land carnivores of all time; the largest complete specimen, located at the Field Museum of Natural History under the name FMNH PR2081 and nicknamed Sue, measured 12.3 meters (40 ft) long, Hutchinson et al.
Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail.
The abundance of fossil material has allowed significant research into many aspects of its biology, including its life history and biomechanics.
The feeding habits, physiology and potential speed of Tyrannosaurus rex are a few subjects of debate.
Its taxonomy is also controversial, as some scientists consider Tarbosaurus bataar from Asia to be a second Tyrannosaurus species while others maintain Tarbosaurus is a separate genus.
Several other genera of North American tyrannosaurids have also been synonymized with Tyrannosaurus.
More than 50 specimens of Tyrannosaurus rex have been identified, some of which are nearly complete skeletons.