tyrannosaurus

Any of a genus Tyrannosaurus of gigantic flesh-eating dinosaurs, order Saurischia, that lived in North America and Asia about 70 million years ago. They had two feet, were up to 15 m/50 ft long, 6.5 m/20 ft tall, weighed 10 tonnes, and had teeth 15 cm/6 in long.

Only a few whole skeletons are known; the most complete was discovered in 1989 in Hell Creek, Montana, and preserved in the Museum of the Rockies, Bozeman, Montana, USA.

Two distinct body types have been discovered for tyrannosaurs, indicating that one, the larger more robust form is female, as it has a wider pelvis. Estimates for the speed at which tyrannosaurs could run down their prey ranges from about 25 kph to 36 kph, but as only single footprints have only been found to date, this is impossible to verify.

US archaeologists proved in February 1997 that tyrannosaurs had a biting force of 1,400 kg/3,000 lb, by analysing bite marks in the fossil skeleton of a triceratops and using these to create replica teeth. They then measured the force necessary to reproduce the marks in a cow skeleton using the replica teeth.