Edmontosaurus

Edmontosaurus was one of the most successful and widespread herbivores of the Late Cretaceous, thriving in North America right up until the end-Cretaceous extinction event. Reaching lengths of up to twelve or thirteen metres, this broad-beaked duck-billed dinosaur lived in vast herds that ranged across coastal floodplains from Alberta down to Colorado. Spectacularly preserved mummies have provided unprecedented details of its anatomy, showing scaled skin textures, hoof-like nail mittens on its front feet, and in one specimen, an unexpected fleshy soft-tissue crest atop the head reminiscent of a rooster comb. Inside its jaws were complex batteries of hundreds of teeth capable of pulverising fibrous twigs, leaves, and pine needles. Edmontosaurus was a primary food source for large apex predators of the period, most notably Tyrannosaurus rex.

A mummified skull revealed it had a fleshy cock's comb crest entirely unsupported by bone.

Where and when

Edmontosaurus lived in the Late Cretaceous, from 73 to 66 million years ago (Campanian-Maastrichtian age). Its remains come from Canada and United States, in the Hell Creek Formation.

The numbers

Length 12 m (estimates run from 11 to 13 m). Mass about 5.5 t. Hip height about 3.8 m. That is 7.1 human-lengths, or 1.07 of a double-decker bus. These are estimates from near-complete skeleton; fields marked estimated by the site are length, mass, hip height.

Compare Edmontosaurus with a bus Place on the timeline