The duck-billed dinosaurs, Hadrosaurids, are members of the ornithischian family Hadrosauridae. They are identified by the flat duck bill appearance of their snouts.
The ornithopod family, which includes genera such as Edmontosaurus and Parasaurolophus, was a common group of herbivores during the Late Cretaceous Period. They were the most dominant herbivores during the late Cretaceous in Asia and North America.
Like other herbivores they have the predentary bone (Pelvic structure similar to birds) and pubic bone positioned backwards in the pelvis. Their teeth are stacked in complex dental batteries (hundreds of teeth stacked in rows upon rows perfect for grinding plant foods).
They are facultative bipeds with the young walking on two legs and the adults on all four. They were discovered in 1954-1856 by Ferdinand Vandeveer Hayden while exploring Judith River in central Montana.
The duck-billed dinosaurs have the the flattened and laterally stretched rostral bones. Some have, probably just for display, massive crests on their heads. Others a skull that is flat and broadened out to form a beak ideal for clipping off plants and twigs.
They lived about 65-75 million years ago, had small brains and are considered similar to cattle, not ducks. They were gentle creatures, wandering the woodlands and plains. They had thick, squat torsos, massive, inflexible tails, and tough beaks. Baby foot prints have been found.