Edmontonia is an ankylosaur, a type of plant-eating, armoured dinosaur that was covered in bony plates called osteoderms. These osteoderms took different forms in different ankylosaurs. Ankylosaurus, for example, had bony plates, a club tail and four large pyramid-shaped horns projecting from its skull, while Edmontonia lacked a club tail, but had spiky osteoderms.
Ankylosaurs had a worldwide distribution, although they are yet to be found in Africa. In Late Cretaceous North America, Edmontonia lived along the western shore of a shallow sea. Home was a coastal plain with a sub-tropical, warm, humid climate. In the Isle of Wight, Polacanthus lived in a riverine, floodplain environment.
Most ankylosaurs had small, leaf-shaped teeth for cropping vegetation. Unlike other herbivorous dinosaurs, like ceratopsids and hadrosaurs, ankylosaurs did not have batteries of teeth, which means they would not have been as effective in grinding up plant material.
Ankylosaurs like Edmontonia had a highly developed sense of smell, thanks to an extensive and uniquely folded nasal passage. This would have helped them seek out food as well as avoid predators.
Barnum Brown discovered a number of fossils of Ankylosaurus, the largest ankylosaur. The first reconstructions were made without the animal's characteristic tail club. Then in 1910, Brown discovered his third fossil of Ankylosaurus in the Scollard Formation. It included a complete skull, the first known tail club, ribs, limb bones and armour. These fossils are housed at the American Museum of Natural History.
Height: 2m (6.56ft)
Length: 6.6m (21.65ft)
Weight: 3.5 tonnes (3.92 short tons)
Top speed: 10kph (6.21mph)
Vision: Edmontonia probably had relatively bad vision.
Skin: Edmontonia had massive bony plates and knobs of bone embedded into their skin. This was overlain by a tough, horny layer of keratin. Edmontonia's plates were not fused together, allowing their armour to deform slightly under pressure and making the animal more immune to puncture wounds. The bones within Edmontonia's triangular skull were fused, which imparted greater strength.
Brain: Ankylosaurs like Edmontonia had the smallest brains relative to body size of any dinosaur.
Prey: Its hindlimbs were longer than its forelimbs and its skull was set low, allowing it to take advantage of tender, ground-level plants and ferns.
Bite: Edmontonia did not spend much time chewing its food. Its large barrel-shaped body suggests food might have been digested by fermentation, like a modern-day cow.
Nest: We can guess from similar dinosaurs that ankylosaurs like Edmontonia laid eggs much like modern turtles, and they would have deposited 20-30 rounded eggs in a heap.