Edmontosaurus was a large duck-billed dinosaur that lived near the end of the Late Cretaceous Period, about 73 to 66 million years ago. It is one of the best-known hadrosaurs because paleontologists have found many skulls, skeletons, skin impressions, and even mummified fossils. Its fossils help scientists reconstruct ancient floodplains, plant-based diets, herd behavior, and predator-prey relationships.
Studying Edmontosaurus shows how evidence from bones, rocks, and trace fossils can reveal the life of an extinct animal.
Key Facts
- Edmontosaurus lived about 73 to 66 million years ago during the Late Cretaceous Period.
- Adult Edmontosaurus could reach about 12 to 13 m in length and may have weighed about 3 to 4 metric tons.
- It was a hadrosaur, a group often called duck-billed dinosaurs because of their broad, flattened snouts.
- Its dental batteries contained hundreds of teeth that were continuously replaced for grinding tough plants.
- Speed = distance ÷ time can estimate walking or running pace from trackways if distance and time are known.
- Relative dating places fossils in order by rock layers, while radiometric dating estimates numerical ages using radioactive decay.
Vocabulary
- Edmontosaurus
- Edmontosaurus was a large herbivorous duck-billed dinosaur from western North America in the Late Cretaceous.
- Hadrosaur
- A hadrosaur is a plant-eating dinosaur with specialized jaws and dental batteries for processing vegetation.
- Dental battery
- A dental battery is a tightly packed set of many replacement teeth that formed a grinding surface in some herbivorous dinosaurs.
- Fossilization
- Fossilization is the process by which remains or traces of organisms are preserved in rock over geologic time.
- Floodplain
- A floodplain is a flat area near a river where sediments are deposited during floods, often preserving fossils.
Common Mistakes to Avoid
- Calling Edmontosaurus a meat-eater is wrong because its skull, beak, and grinding teeth show adaptations for eating plants.
- Assuming every large dinosaur walked on four legs all the time is wrong because Edmontosaurus could move on two legs and also support itself on all fours while feeding.
- Treating fossil skin impressions as proof of exact color is wrong because impressions preserve texture and scale patterns, not usually the original pigments.
- Thinking one fossil skeleton tells the whole species story is wrong because scientists compare many specimens of different ages, sizes, and locations to build a stronger interpretation.
Practice Questions
- 1 An Edmontosaurus skeleton is 12.5 m long. If a museum display is built at 1:25 scale, how long should the model be in meters?
- 2 A trackway shows an Edmontosaurus traveled 48 m. If it took 24 s to cover that distance, what was its average speed in m/s?
- 3 A fossil bed contains Edmontosaurus bones, plant fossils, river sediments, and scattered shed teeth from a predator. Explain what this evidence suggests about the environment and possible interactions in that ecosystem.