The Tyrannosaurus Rex was a very large theropod Dinosaur. It was the largest of it's genus. (being the Tyrannosaurus genus) It is the most popular Dinosaur in the world. It lived throughout North-Western America, and was much more widespread then the other tyranosaurids, suggesting it's succes. The fossils of this creature are usualy found in rock-formations dating three million years ago, in the Cretaceous period, approximately 68 to 65 million years ago. It was among the few dinosaur species to exist just before the mass extincion that marked the end of the Cretaceous period.
The Tyrannosaurus Rex (ore T.Rex in popular culture) had a very large skull balanced by a large, heavy tail. The T.Rex had very shot front limbs altough these were remarkably powerfull. The T.Rex was rivaled in size by other therapods in it's period, but still it's massive weight made the creature one of the largest land predators that ever existed, with a stunning 16 metres in length (52 ft), 8 metres tall and with a weight of nearly 18 tons. Due to it's size it was probably an apex predator, altough some experts believe it to be a scavenger, this is still a point of discussion.
Alot of specimens of the Tyrannosaurus have been identified some of which are nearly complete skeletons. Also soft tissue and proteins have been found in some specimens, this has given scientists a good look of the creature's biomechanics, physiology and feeding habits.
This is the Tyrannosaurus' skull. It reaches 1,5 metres in lenght (5 feet). It has large openings to reduce weight and provide areas of muscle attachment. The skull is extremely wide at the rear but has a narrow snout, giving the beast a very good binocular vision which helps it to hunt. The bones of the skull are massive but pneumatized, making them strong but flexible. Further the skull has several features which trends toward an extremely powerfull bite, which surpassed that of all other carnivores of it's time. The tip of the upper jaws is U-shaped allowing the beast to rip off huge amounts of tissue with each bite, this and many other aspects of the Tyrannosaur skull suggest that the creature was in fact a predator, and not a scavenger.
The image above shows a front limb of a Tyrannosaurs specimen. It looks very small and looks vestigial. This is incorrect however since it shows large areas of muscle attachment indicating considerable strength. The biceps of a Tyrannosaurus Rex was capable of lifting 199 kilograms! This number would increase offcource because there are other muscles acting in concert with the biceps. The strenght of the limb suggests it was used to hold captured prey just before the huge jaws could finish it, again suggesting that the Tyrannosaurus Rex was indeed a predator.In the american classic film jurassic park the tyrannosaurus was smoothly in inaccurate in both height and length however the velociraptors were as tall as a person when really they were about the size of a turkey or chicken.