Which dinosaur had a mouth so big that a cow could have fit inside? Give up? It was Tyrannosaurus Rex. The dinosaur's 50 sharp teeth, however, would have made its mouth an uncomfortable place for any creature to find itself inside of. Let's try another one: Which dinosaur could run 45 mph [72.4 kmh]? Struthiomimus, of course - the world's fastest dinosaur. These and other details about dinosaurs along with amazing illustrations will keep any young reader turning the pages. Developed by literacy experts, Amazing Dinosaur Facts features controlled text with appropriate vocabulary, grammar, and sentence structure for emergent readers.