The Tyrannosaurus Rex lived 65 million years ago in the forested valleys of North America. The T-Rex is often known as the king of all dinosaurs. Its name means ‘tyrant lizard’ in Greek and as far as we know from studies this massive beast lived up to its name. There were larger dinosaurs and possibly even dinosaurs that may have dined upon the T-Rex themselves but those dinosaurs died out from defects that, in the end, made them evolutionarily weaker than the T-Rex. The T-rex was built to be killer. It had strong jaws, a large heavy tail, strong hind limbs, and even though it’s fore limbs were short than were unusually powerful for their size. These short powerful arms featured two clawed digits.