Tyrannosaurus Rex (TIE-ran-oh-SORE-us rex) Meat eater, 40 feet long, Late Cretaceous period. 65 million years ago located in western North America, Montana T. rex was the smartest and most powerful of all giant meat-eating dinosaurs. It had the most powerful bite of any animal ever. T. rex had 50 sharp teeth the size of bananas. It could chomp 500 pounds of dinosaur meat in one bite.