Edmontosaurus ("lizard from Edmonton") is a hadrosaurid dinosaur species from the Maastrichtian, the last phase of the Cretaceous period, 71-65 million years ago. A fully-grown adult could have been up to nine meters long, and some of the larger species reached thirteen meters. Its weight was in the region of 3.5 tons, making it one of the largest hadrosaurids. Edmontosaurus could pass the toughest foodstuff back and forth across the teeth with its muscular daring pouches.
To fit so many teeth into its mouth, they were packed into tight "banks" of up to sixty rows, and new teeth continually grew to replace lost teeth — analogous to a new shark. The bones of the higher jaw would flex outwards as lower jaw came up, so the mandible could grind against it. Typical food would have built-in conifer needles, seeds, and twigs, and these have been establishing in the body cavities of fossilized Edmontosaurus. It was evidently a tree-browser.
The 1908 discovery in Wyoming was particularly remarkable in that paleontologists actually recovered fossilized imprints of Edmontosaurus' skin. The skin drying very quickly and fixing its shape into the mud must have left the impression. It is from these limitations that we know the skin was scaly and leathery, and the thigh muscle was under the skin of the body. This would have given the feeling that the leg left its body at the knee, and the whole thigh was under the skin. This only contributes to its resemblance to a duck. It also had a number of tubercles (bumps) on its neck and down its back and tail.