The most famous of the duck-billed dinosaurs, Edmontosaurus had short forelimbs, a long, pointed tail, feet fitted with three toes. The head was flat and ended with a beak. A herbivore it chewed food with nearly a thousand small cheek teeth. Its size could reach 13 meters and weigh 3.5 tons.
The early specimens discovered in the 1890s were named Claosaurus by Othniel Charles Marsh, who illustrated them as being fully bipedal. Later research has suggested it could also walk on all four legs to graze low lying vegetation. The stomach contents of the top carnivores of the time, and bite marks found on tail bones strongly suggest that Edmontosaurs were firmly on the menu for late Cretaceous therapod dinosaurs.
Living alongside fellow giants Triceratops and Tyrannosaurus rex, it was one of the last dinosaurs to walk the earth before their mass extinction 65 million years ago.