T-rex Coloring Pages: The T-Rex, also known as Tyrannosaurus rex, was one of the largest and most fearsome dinosaurs to have ever roamed the earth. It stood about 15-20 feet tall, with a length of around 40 feet. Its body was covered in scales, with short arms and sharp claws. Its most distinguishing feature was its massive head, filled with rows of large, sharp teeth that could grow up to 12 inches long. The T-Rex also had powerful hind legs, allowing it to run at speeds of up to 20 miles per hour. Overall, the T-Rex was a formidable predator, capable of taking down even the largest of prey with ease.