Tyrannosaurus Rex - Meaning : Tyrant Lizard

The name 'Tyrannosaurus' came from the Greek language meaning 'Tyrant Lizard'. Like all dinosaurs the Tyrannosaurus Rex (Pronounced tie-RAN-o-SAWR-us rex) was a reptile. It lived during the late Cretaceous period, about 85 million to 65 million years ago. T. rex lived in a humid, semi-tropical environment, in open forests with nearby rivers and in coastal forested swamps.

Tyrannosaurus rex was one of the largest land carnivores of all time, about 12 to 13 metres (40 to 43.3 feet) long and 4.5-5 metres (14-16 feet) tall, when fully-grown. They weighed between 6 - 7 and a half tons. Which makes them the heaviest dinosaur in history. The largest known T. rex skulls measure up to 1.5 metres (5 ft) in length. Their skull was extremely wide with a narrow snout, allowing some degree of binocular vision, meaning 'both eyes are used together', like human beings. Plant eating dinosaurs just had eyes on the sides of thier heads and did not have this binocular vision. This was because they were not predator animals, however, the T. rex was.

T. rex displayed remarkably sharp teeth which included incisors, canines ('eyeteeth'), premolars, and molars with the premaxillary teeth (a pair of small cranial bones at the very tip of the jaws) at the front of the upper jaw closely-packed and D-shaped in cross-section. Large bite marks found on bones of other dinosaurs indicate that these teeth could penetrate solid bone. T. rex had the greatest bite force of any animal. Worn or broken teeth are often found, but unlike those of mammals, tyrannosaurid teeth were continually replaced throughout the life of the animal. T. rex could eat up to 500 pounds (230 kg) of meat and bones in one bite.

Tyrannosaurus rex had a wrap-around overbite which means that when T. rex closed its mouth, the upper parts of the lower jaw's teeth fit inside the upper teeth.

The neck of T. rex formed a natural S-shaped curve like that of other theropods, but was short and muscular to support the massive head. The two-fingered forelimbs were very small when compared to the size of it's body. In contrast, the hind limbs were among the longest in proportion to body size of any theropod. The tail was heavy and long, sometimes containing over forty vertebrae, in order to balance the massive head and torso. To compensate for the immense bulk of the animal, many bones throughout the skeleton were hollow. This reduced the weight of the skeleton while maintaining much of the strength of the bones.

Fossilized specimens of T. rex's rough, scaly skin have been found. It is said that their skin was bumpy, like an crocodile's skin, and has been described as being rather 'pebble' like.

The life span of the T. Rex is quite unknown. However, fossil records have determined that a male T. rex had only grown for two years before dying, whereas a female lived for around 28 years. This is considered the maximum age for this species of dinosaur. Over half of the known T. rex specimens appear to have died within six years of reaching sexual maturity, a pattern which is also seen in other tyrannosaurs and in large, long-lived birds and mammals today.

Take a look at the Tyrannosaurus Anatomy and Reproduction.