The Tyrannosaurus, or Tyrannosaurus rex, is one of the most recognizable and feared dinosaur species to have ever existed. It lived during the Cretaceous period, about 68 to 66 million years ago, in what is now North America. Weighing up to nine tons and measuring approximately 12 meters in length, the Tyrannosaurus was a formidable predator, possessing one of the most powerful bites ever recorded. Its jaws, lined with serrated teeth, and its short but muscular forelimbs indicate its specialization as a hunter.