Tyrannosaurus rex
Tyrannosaurus rex was a predatory dinosaur. This is probably the most famous and most fearsome predator of all times (Cretaceous, 85-65 million years ago), its name meaning 'terrible king lizard'. It is a very rare animal -- as of 2001 only 20 specimens are found, including only three complete skulls. This theropod dinosaur was first found by Barnum Brown, in the early 1900s.
T. rex could reach a length of up to 14 metres (45 feet) and may have weighed over 5 tonnes. Like other theropods, T. rex had recurved teeth that ensured that meat was pulled free when biting their victims. All food was swallowed whole, since these dinosaurs never developed any chewing mechanism. T. rex had only its teeth as a weapon (in contrast to for instance raptors, who also used their toe claws). The arms of T. rex were small, perhaps to make up for the weight of its enormous head, but were very sturdy. Paleontologists continue to pass the time arguing about what role, if any, they played. Compared to other carnivorous dinosaurs, the skull of Tyrannosaurus is heavily modified. Many of the bones are fused together, eliminating movement between them. The bones themselves are much more massive than typical of a theropod, and teeth, far from being bladelike, are massive and oval in cross-section. Bite marks on bone and heavy wear on the teeth indicate that these teeth could bite into solid bone. Relative to other carnivorous dinosaurs such as Allosaurus, Tyrannosaurus appears to have had a sizeable brain, but it was probably not particularly intelligent by mammalian standards. Much of Tyrannosaurus' biology- its lifespan, its breeding strategy, what color it was, etc. remains unknown. A site in Alberta has a large number of individuals of the related Albertasaurus preserved together, but whether these animals were together in life, or formed any kind of social group, is open to argument.
Given the size of T. rex, and combined with the fact that they were almost certainly warm-blooded, paleontologist James Farlow calculated the number of lawyers a grown Tyrannosaurus had to eat (based on a scene from the movie Jurassic Park, in which a lawyer became T. rex fodder) to stay alive. Taken an average weight of 68 kilograms, 292 lawyers would be needed to keep one T. rex happy for a year!
The discussion about the feeding patterns of T. rex, and other large predatory dinosaurs hasn't finished. Some paleontologists have portrayed them as highly active predators, while others see them as scavengers. The available evidence of bite marks in other animals and even other T. rex, combined with the enormous serrated teeth and large jaw seem to speak in favour of a role as predator. Another theory is that their size and power allowed them to steal kills from smaller predators. Of course, few animals will pass up a chance for a free meal, so probably T. rex did scavenge, the question is whether it hunted at all. Although not much is known about the vision of T. rex, the skulls clearly show that the eye sockets are positioned in such a way that they had binocular vision. Binocular vision is typically seen in active predators such hawks, owls, and cats.J von Arrensdorff speculates that Tyrannosaurus may have used a similar strategy to that of the Komodo Dragon relying on one bite followed by steady pursuit of its stricken prey. A number of other giants carnivorous dinosaurs-, including Carcharodontosaurus, Giganotosaurus, Acrocanthosaurus, and a giant specimen of Allosaurus- are now known. Giganotosaurus actually appears to have been larger than Tyrannosaurus. There is still no clear scientific explanation for exactly why these animals grew to such tremendous sizes.
T. rex was not the only Tyrannosaurus around. The following species have been identified:
(measurements given are based on found fossils and estimates)
T. torosus (Russell, 1970)
- Skull length : 1.1 m.
- Total length : 9 m.
- Hip height : 2.5 m.
- Weight : 2.3 tonnes
- Skull length : 1.35 m.
- Total length : 10 m.
- Hip height : 2.9 m.
- Weight : 5 tonnes
- Skull length : 1.75 m.
- Total length : 13.6 m.
- Hip height : 4.4 m.
- Weight : 12 tonnes
Barnum Brown's T. rex fossil is now on display at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania.
Susan Hendrickson, amateur paleontologist, discovered the most complete and largest Tyrannosaurus rex fossil skeleton currently known, in South Dakota on August 12, 1990. The T. rex, now named Sue, in her honor, is currently exhibited at the Field Museum of Natural History. Researchers report that a sub-adult and a juvenile skeleton were found in the same quarry as Sue; this lends evidence to the possibility that T.rex ran in packs or other groups.
The Tyranosaurus rex is actually a member of the tyrannosaurids family of dinosaurs. The gigantic theropods are believed to have required extensive geographic feeding ranges - as large as a continent, and that theropods the size of T. Rex arose in response to the retreat of the Western Interior Seaway of North America, 69 million years ago, which would have increased the size of the feeding range. (Scientific American, 290, no. 2, February 2004 pp. 23-24)
Tyranosaurus Rex was also the original name of the 1970s pop group T. Rex founded by Marc Bolan.