Edmontosaurus, Late CretaceousHell Creek Formation, Montana · named 1917
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Edmontosaurus

ed-MON-toe-SORE-us

"lizard from Edmonton"

Lived
84 to 66 million years ago, Late Cretaceous
Diet
Herbivore
Length
about 12 m (39 ft)
Group
Ornithopods, Hadrosauridae
Found in
United States and Canada
Named by
Lambe 1917

Size comparison

To scale

Where its fossils were found

The evidence

Today

68 finds

75 million years ago

Map: C. R. Scotese, PALEOMAP

Habitat

In Hell Creek it lived on river floodplains with forests, wetlands and low-growing vegetation. Its neighbors included Triceratops, Thescelosaurus and Tyrannosaurus.

A Dinosaur Vault film

You Hatch in the Arctic. Then the Sun Disappears.

Baby dinosaur fossils from northern Alaska show that dinosaurs nested in the ancient Arctic. Follow a young hadrosaur as its polar forest heads into months of darkness.

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Field notes

About Edmontosaurus

What it was like

Edmontosaurus was a large plant eater with a wide, flattened beak used for cropping plants, and rows of tightly packed teeth further back in its jaws for grinding tough food. It grew to about 12 meters (39 feet) long, making it one of the largest duck-billed dinosaurs known.

Unlike some of its relatives, it had no tall bony crest on its head, just a smaller, fleshy comb. It probably walked on four legs while feeding but could run on two, and well-preserved skin impressions show it was covered in small, bumpy scales.

Its world

Edmontosaurus lived from about 84 to 66 million years ago, during the Late Cretaceous, across a wide part of what is now the United States and Canada, including Montana, Alberta, Wyoming, South Dakota, Alaska, and Colorado.

It lived alongside Triceratops, Pachyrhinosaurus, and Tyrannosaurus, among the last dinosaurs to exist before the Cretaceous came to an end. Bones found together in large groups suggest Edmontosaurus lived and may have moved in herds.

How it was found

Lambe named Edmontosaurus in 1917, from fossils found in Alberta. It is now one of the best known dinosaurs, with 68 finds recorded, and its close relatives include Saurolophus, Maiasaura, and Parasaurolophus, other duck-billed dinosaurs from around the same time.

Lived alongside

Found in the same rock formations

A rock formation can hold fossils laid down millions of years apart, so not every animal here met Edmontosaurus.

The evidence

The science behind Edmontosaurus

Which parts of the picture come from its own bones, and which come from its relatives.

From its own fossils

  • Many skeletons show a broad beak, tightly packed grinding teeth, strong hindlegs and a long, muscular tail.
  • Mummified specimens preserve pebbly scales and soft tissue around the body and hands.
  • A mummified specimen preserves a fleshy comb on top of the head.

Borrowed from relatives

  • Almost the whole body is known from its own skeletons and preserved skin, so little needs to be borrowed from relatives.

Still unknown

  • Its skin color and markings.
  • How widespread fleshy head combs were among its species.
  • Whether adults cared for their young.

Often drawn wrong

  • Its hands formed compact supports for walking, rather than broad paddles for swimming.
  • It had no hollow bony crest like Parasaurolophus and no thumb spike like Iguanodon.

Discovery timeline

  1. 1917Named itLambe
  2. 2009How it fedWilliams, Barrett & Purnell
  3. 2011SkullsCampione & Evans
  4. 2014SkinBell et al.

Key papers

The research behind what we know of Edmontosaurus

Close relatives

Other members of Hadrosauridae

Sources: Wikidata