Tyrannosaurus rex (TIE-ran-oh-SORE-us rex) Meat-eater 40 feet long Late Cretaceous, 65 million years ago 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.