Edmontosaurus was one of the largest hadrosaurs. At 40 feet long and 5 tons in weight, it was as long as a bus and as heavy as an elephant. These plant-eaters had thousands of tightly packed teeth perfect for chewing. Some skeletons of Edmontosaurus have been found with fossil skin. The skin shows what the texture and placement of the dinosaur's scales would have been like. This dinosaur lived 65 million years ago in North America.