Was This Gigantic Dinosaur Really Prey For The T-Rex?

Edmontosaurus 3D

Written by Austin S.

Updated: October 14, 2022

Share on:


The Cretaceous Period saw the existence of one of the most voracious prehistoric animals, the dinosaurs. Dinosaurs were prehistoric reptiles that dominated the earth over 160 million years ago. Most of these reptiles dominated the Cretaceous Period.

Dinosaurs possessed various adaptive features that contributed to their success. These prehistoric reptiles were embedded with claws, wings, and diversified dentitions. Dinosaurs had a wide range of diets ranging from plants during the Cretaceous Period and the lower aquatic and terrestrial animals of the period.

Among these voracious predators were the Giant Edmontosaurus dinosaurs.  Edmontosaurus was a genus of duck-billed dinosaurs that had only two known species: Edmontosaurus regalis and Edmontosaurus annectens. This class of dinosaurs is our topic of interest.

Description And Size

Edmontosaurus was coined from the Greek word “Edmonton” which means lizard. Edmontosaurus is a genus of hadrosaurid dinosaurs. This class of dinosaurs was among the last non-avian dinosaurs, and it existed simultaneously with dinosaurs like Tyrannosaurus and Triceptors.

Edmontosaurus had a massive body encompassing a head with a duck-like beak and ended in a long and broad tail. Adult Edmontosaurus could grow as long as 9 meters  (30ft). The exceptional ones were about 13 meters (43ft) long. Edmontosaurus dinosaurs also had massive weights. An average Edmontosaurus weighed about 4.4 metric tons ( about 9000 pounds).

The skull of an adult Edmontosaurus measured about a meter long. Their skulls had an irregular triangular shape devoid of bony cranial crests. The superior view of the skull showed an enlarged rear and an expanded front that formed the duck-bill shape.

The number of backbones varied with the species. Those that belonged to Edmontosaurus regalis possessed thirteen cervical vertebrae, eighteen back vertebrae, nine hip vertebrae, and an uncertain number of tail vertebrae.

These dinosaurs possessed an arched back with an upwardly directed neck. The rest of its body was held horizontally. Most of the back and tail were composed of ossified tendons arranged in a regular pattern along the vertebrae. This arrangement fortified its stature and gave the tail a ramrod-straight appearance.

The hindlimbs of Edmontosaurus were more robust than their forelimbs, even though these animals used both limbs for standing and movement. The forelimbs had a massive deltopectoral crest for muscle attachment; they entailed an upper arm and a forearm of almost equal lengths. 

The forelimbs ended in four fingers. The hind limbs also had a strong ridge for muscle attachment. The forelimbs had two feet, each with three toes that had hoof-like tips.

What Did Edmontosaurus Eat?

Edmontosaurus was a giant terrestrial herbivore. The animal fed on nutritious plants and trees that existed during the Cretaceous Period with a feeding range of about 4 meters above the ground.

The beaks were keratinized and had no teeth attached to them. Only the upper jaw had teeth attached to it; the lower jaw contained dentaries. Edmontosaurus had six types of tissues that made up the teeth, making it a very complex type.  The teeth took several months to form and were replaced continually.

The animal utilized its broad beak to break down loose food by closing the jaws over the branches of the trees and scraping off the more nutritious leaves and fruits. Based on the anatomical details of their jaws, scientists deduced that Edmontosaurus had muscular cheeks. These muscular cheeks could retain food in their mouth.

Initially, Edmontosaurus were thought to be aquatic and to have fed on aquatic plants. The works of Williams Morris with Edmontosaurus remnants in 1970 further supported this. He was of the notion that the animal had a diet that was similar to that of the modern ducks. They filtered planktons, plants, and other aquatic invertebrates from the water and passed it via the V-shaped furrow in their upper beak. 

However, further studies revealed that the furrows and ridges in Edmontosaurus’ mouth were similar to that of the modern herbivorous turtles; hence, William’s notion was disproved. Nevertheless, both could have been possible.

When And Where Did Edmontosaurus Live?

Edmontosaurus existed during the Late Campanian Stage of the Cretaceous Period. This was about 83.6 million to 66 million years ago.

Edmontosaurus dinosaurs were thought to be social animals that lived in groups and also migrated. They resided across several regions across western North America, ranging from Colorado to the north slopes of Alaska. The sites of discovery of Edmontosaurus fossils connote that the animals preferred coasts and coastal plains. 

Moreover, these duck-billed dinosaurs ranged in both space and time. Towards the southern range, the animal was primarily associated with the older Horseshoe Canyon, the St. Mary River Formations, Hall Creek, and Lance Formations. 

Coming to the Northern range, Edmontosaurus were associated with a single region which is the Liscomb Bonebed of the Prince Creek Formation.

Threats and Predators Of Edmontosaurus 

The significant threats Edmontosaurus faced were the environmental hazards of the Cretaceous Period. During the Cretaceous Period, active volcanoes made the climate warmer. Seafloor spreading often occurred during this period. Furthermore, the caliche deposits found indicate these animals experienced periodic droughts. 

Even though Edmontosaurus had a massive body stature, they were still prey to the carnivorous Tyrannosaurus dinosaurs. Tyrannosaurus dinosaurs were more fierce than Edmontosaurus dinosaurs; hence they attacked Edmontosaurus. Several Edmontosaurus fossils have shown evidence of theropod bites on the tail, jaws, spines, and other body parts.

Where Were Edmontosaurus Fossils Found?

The first well-known fossils of Edmontosaurus were discovered in the Lance Formation of Niobrara County,  Wyoming, in 1891 by John Bell Hatcher. The discovered fossils had a partial skull and skeleton. The other fossil had a complete skull and skeleton. These fossils date back to 66 million years ago, during the Upper Cretaceous Period.

Between 1902 and 1915, two additional specimens of Edmontosaurus were discovered in the Lance Formation rocks, Wyoming, by Charles Hazelius Sternberg and his sons. They recovered an Edmontosaurus fossil in 1908. In 1910, the Sternbergs also discovered a similar specimen in the exact location but less preserved. This specimen was sold to the Senckenberg Museum in Germany

In 1912, Levi Sternberg discovered the fossil of an Edmontosaurus regalis in the Horseshoe Canyon Formation along the Red Deer River of southern Alberta, Canada. This fossil had a skull, some articulated vertebrae, nearly complete hindlimbs, ribs, partial hips, and forelimb bones. Several Edmontosaurus fossils were later discovered at this location. 

In 1916, George Sternberg discovered a second specimen of Edmontosaurus regalis at the exact location. This specimen had a skull without the beak and a skeleton with most of the tail and part of the feet intact.

In 1917, Lawrence Lambe discovered two partial skeletons of Edmontosaurus in the same Horseshoe Canyon Formation.

In 1921, Charles Sternberg collected specimens of Edmontosaurus from rocks that belonged to the Lance Formation. This fossil had an intact skull with several vertebrae and limb girdles with partial hind limbs.

When Did Edmontosaurus Go Extinct?

Edmontosaurus were among the last dinosaurs that existed. These prehistoric animals went extinct due to the Cretaceous Period mass extinction event, which brought an end to the age of dinosaurs. Numerous geographical evidence connotes that a massive asteroid that hit the earth at the end of the Cretaceous Period led to the extinction of dinosaurs.

Scientists believe the asteroid’s impact would have created a tremendous dust cloud that encircled the earth. The dust cloud must have significantly reduced the amount of sunlight on the Earth’s surface.

With little sun reaching the earth, plants died. The more miniature plants also meant less for herbivores, so the elimination process started. Also, the impact of the asteroid, as well as the dust and debris falling to the Earth, must have triggered a widespread wildfire.

Similar Animals to Edmontosaurus


Spinosaurus remains the largest of all known terrestrial carnivores. Spinosaurid dinosaurs were about 41 to 59 ft in length and 7 to 20.9 metric tons in weight.

Spinosaurus had massive, robust forelimbs with three-fingered hands, with an enlarged claw on the first digit, and possessed straight conical teeth.


Tyrannosaurus retains its position among the largest known land predators and is believed to have exerted the strongest bite force among all terrestrial animals. It was a bipedal carnivore with a giant skull, large tail, and powerful hind limbs


Allosaurus are giant carnosaurian theropod dinosaurs that lived about 155 to 145 million years ago during the Late Jurassic epoch. These dinosaurs were large bipedal predators. These giant reptiles were about 32ft long and had large skulls with sharp teeth.


Giganotosaurus was one of the largest known terrestrial carnivores, with its teeth compressed sideways and with serrations. The neck was strong and the pectoral girdle proportionally. The complete specimen of Giganotosaurus ranges from 12 to 13 m (39 to 43 ft) and weighs 4.2 to 13.8 t (4.6 to 15.2 short tons).

Up next; If you’ve enjoyed reading about this ancient animal and you’d love to find out about some other carnivorous dinosaurs, click the links below.

Share this post on:
About the Author

Growing up in rural New England on a small scale farm gave me a lifelong passion for animals. I love learning about new wild animal species, habitats, animal evolutions, dogs, cats, and more. I've always been surrounded by pets and believe the best dog and best cat products are important to keeping our animals happy and healthy. It's my mission to help you learn more about wild animals, and how to care for your pets better with carefully reviewed products.

Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.