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Tyrannosaurus Rex (meaning 'tyrant lizard'), is a genus of theropod dinosaur. The species Tyrannosaurus rex ('rex' meaning 'king' in Latin), commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other tyrannosaurids. It lived in the Late Cretaceous, 68 - 65 million years ago. Each tooth was the size of a banana, and there were sixty of them in its mouth, which could bite down with twice the force of a great-white shark. It was among the last non-avian dinosaurs to exist prior to the Cretaceous–Tertiary extinction event.


Fact File

Length: 12 - 15 metres


Height: 4-6 metres

Weight: Up to 7-12 tonnes

Diet: Carnivorous

Tyrannosaurus rex was a fierce predator that walked on two powerful muscular legs.It had a huge head with large,pointy teeth and well developed muscles.It had small arms,each with two fingers.Each bird-like foot had three large toes,all equipped with claws,plus a smaller dew claw on a vestigial toe.

Tyrannosaurus had a slim,stiff pointed tail which provided balance and allowed quick turns while running.The rear part of the tail was stiffened by interlocking vertebral zygopophyses.T.rex's neck was short and muscular.Its body was solidly built but its bones were hollow.Tyrannosaurus rex was up to 40 feet (12.4 m) long, about 15 to 20 feet (4.6 to 6 m) tall. The arms were only about 3 feet (1 m) long. Tyrannosaurus rex was roughly 5 to 7 tons in weight. The enormous skull was about 5 feet (1.5 m) long.

The eye sockets in the skull are 4 inches (10.2 cm) across; the eyeballs would have been about 3 inches (7.6 cm) in diameter.T. rex's jaws were up to 4 feet (1.2 m) long and had 50 to 60 thick, conical, bone-crunching teeth that ranged in size from very small to over 9 inches (23 cm) long. Adult had a variety of sizes of teeth in their jaws at one time, as teeth were broken and new (smaller) ones grew in to replace them.

One T. rex was found with some teeth up to 13 inch (33 cm) long. T. rex could eat up to 500 pounds (230 kg) of meat and bones in one bite! Tyrannosaurus rex had a wrap-around overbite; when T. rex closed its mouth, the upper parts of the lower jaw's teeth fit inside the upper teeth.Fossilized specimens of T. rex's rough, scaly skin have been found.It was bumpy, like an alligator's skin, and has been described as a "lightly pebbled skin." Tyrannosaurus rex probably lived in forests, where its prey (plant-eating dinosaurs) could find plenty of food.Among its contemporaries were Triceratops,Ankylosaurus and many species of hadrosaurs which were a food source for T.rex.There were also pther reptiles,like crocodiles and turtles,fishes,small mammals,ginat insects and pterosaurs.T. rex fossils have been found in western North America.Tyrannosaurus had large visual lobes in its brain that processed visual information.It also had depth perception About 30 incomplete Tyrannosaurus rex fossils have been found.One T.rex footprint has been found in an undisclosed location in New Mexico,U.S.A.Fossilized T.rex dung has also been found.The first Tyrannosaurus rex was first found by Barnum Brown in 1902, in Hell Creek, Montana.


T-rex would have hunted prey like Edmontosaurus, Parasaurolophus, Triceratops and Ankylosaurus. It may have actually hunted them actively, or scavenged their carcasses, but most likely it did both. T-rex could crush bone, allowing it to digest nutritional parts like the marrow, which other dinosaurs couldn't reach. Tyrannosaurus couldn't chew, so it swallowed meat whole. They may have competed over carcasses, or even hunted in packs. Tyrannosaurus rex may have been an apex predator, preying upon hadrosaurs and ceratopsians, although some experts have suggested it was primarily a scavenger. The debate over Tyrannosaurus as apex predator or scavenger is among the longest running debates in paleontology.

Famous Tyrannosaurus Rexes


Sue was a Tyrannosaurus discovered in 1990 by palaeontologist Sue Hendrickson. Sue is the most complete and well-preserved T-rex ever, as well as being the largest. The skeleton was auctioned in October 1997 for US $7.6 million, the highest ever paid for a dinosaur specimen. Sue currently resides at the Chicago Field Museum.


Stan was a male Tyrannosaurus found in South Dakota by Stan Sacrison, and excavated by Peter Larson.

AMNH 5027

This Tyrannosaurus has no actual name, but is famous nonetheless. It was discovered in Montana in 1907 by Barnum Brown, and was the first complete skeleton. It currently is exhibited in the American Museum of Natural History and was even mentioned in the novel Jurassic Park.

London Natural History Museum's Robotic T-Rex

In the Natural History Museum at London there is a robotic T-rex. It is only adolescent, but it is still very large. Its head moves, to make it seem lifelike.

Popular Culture

Main Article: Tyrannosaurus in popular culture