Illustration of a Parasaurolophus dinosaur. Parasaurolophus was a hadrosaurid or duck-billed dinosaur. It lived in North America during the Upper Cretaceous period, 75-65 million years ago. It was a herbivore that inhabited grassy plains where it lived in herds. Parasaurolophus reached up to 10 metres in length and weighed up to two tonnes. Scientists believe that these dinosaurs produced sound by forcing air through the hollow crests on their heads.