The Tyrannosaurus rex was a massive carnivorous dinosaur that lived approximately 68 million years ago. It could grow up to 40 feet long and 15-20 feet tall, weighing up to 10,000 pounds. The T-rex had over 50 banana-sized sharp teeth and preyed upon other dinosaurs like the Triceratops and Edmontosaurus. It roamed areas of North America such as South Dakota, Montana, and Canada during the late Cretaceous period.