In some genera, most notably Edmontosaurus, the whole front of the skull was flat and broadened out to form a beak, which was ideal for clipping leaves and twigs from the forests of Asia, Europe and North America. However, the back of the mouth contained thousands of teeth suitable for grinding food before it was swallowed. This has been hypothesized to have been a crucial factor in the success of this group in the Cretaceous compared to the sauropods, which were still largely dependent on gastroliths for grinding their food.
Also, contrary to their earlier depictions, the duckbilled dinosaurs weren't amphibious animals, but lived on land, as did the other dinosaur species; their feet weren't webbed, but ended in hoof-like toes to better move on land. Most of the adult hadrosauroids moved on all fours, but the youngsters regularly walked on hind legs alone, and even the adults could stand up and run if danger threatened.
Hadrosauroids are divided into two families, separated by their crests. The lambeosaurines, like Parasaurolophus, had very elaborate head crests. The hadrosaurines, like Edmontosaurus, had small crests or lacked them altogether. The scientists still haven't fully figured out how the duck billed dinosaurs used their crests, but most likely as a resonating chamber for their calls.
In Walking with... series
Edmontosaurus (identified as Anatotitan) was a Hadrosauroid featured in this episode as a background animal, mostly as prey for such creatures as Deinosuchus and T. rex. Like the other dinosaurs, it died out during the K/T extinction.
This episode featured Saurolophus, a close cousin of Edmontosaurus. At the beginning of the episode, Nigel Marven used Saurolophus to demonstrate how hadrosaur jaws worked, and later on a small herd of Saurolophus fled from a watering hole when a Tarbosaurus came to drink.
Edmontosaurus was one of the featured animals in this movie.
Appearances in other media
Read more at the Prehistoric Park Wiki
Parasaurolophus was a Hadrosauroid in the sixth episode where they're prey for Albertosaurus and Deinosuchus, Nigel Marven also communicated with them by blowing through a seashell.