6 extinct animals that used to call Colorado home

Colorado has changed dramatically in recent geological eras. A report from CU Boulder even suggests that Colorado 500 million years ago had a coastal environment, making it a perfect home for a variety of species to thrive.

Today, Colorado is still known for its incredible variety of species, but here are some that you may not have known once called the Centennial State Home.

1. Stegosaurus







Image credit: CoreyFord. Stock Photo. (iStock)




Paleontologists believe that stegosaurs roamed the Centennial State about 155 million years ago.

Stegosaurus was a Jurassic species estimated to be about 30 feet long and 15 feet high.

The dinosaur is easy to distinguish on the plates along the back. In fact, the word stegosaurus translates to “bony plates” in Greek, but there is some debate about the purpose of the plates.

“One theory is that the plates contained blood vessels, to help regulate body temperature. Another idea is that the plates were used for exhibition to attract comrades, such as colorful feathers on a bird or antlers on a deer,” said the National Park. Service in a post on their website.

Stegosaurus thrived so well in Colorado that it was named the state dinosaur in 1982.

2. Old Camel







Camelops were a herbivorous camel that lived in North America during the Pleistocene.  Image Credit: CoreyFord (iStock).

Camelops were a herbivorous camel that lived in North America during the Pleistocene. Image Credit: CoreyFord (iStock).




Old camels, or camelops, probably called Colorado home 2.6 million years ago. Researchers estimate that they were around seven feet high at the shoulder and weighed around 1800 pounds.

“Like living camels, Camelops had two-toed, planed feet and long neck. At present, paleontologists are not able to determine whether Camelops had a hump on his back like live bacterial and dromedary camels, “according to NPS.

In 2021, crews from the Colorado Department of Transportation discovered Camelops fossils while working on the ‘Central 70 Project’ construction site.







Kamelops hesternus molar fossil.  Photo credit: Kiewit Infrastructure Co.

Kamelops hesternus molar fossil. Photo credit: Kiewit Infrastructure Co.


3. Tyrannosaurus Rex







T-Rex skeleton.  Photo credit: LG-Photography (iStock).

T-Rex skeleton. Photo credit: LG-Photography (iStock).




Fossil evidence suggests that at one point during the Cretaceous, it was the Tyrannosaurus Rex in Colorado. In fact, the first T-Rex teeth were found in Golden, Colorado in 1874.

Tyrannosaurus Rex literally translates to “King of the Tyrant Lizards”, which is an appropriate name for one of history’s most cruel beasts.

Researchers believe that the T-Rex was around 38 feet long, and may have weighed up to 10 tons. They had powerful jaws, a keen sense of smell and were one of the best predators of that time.

4. Ornithomimus







Figures of Ornithomimus

Photo credit: Savany. Stock Photo. (iStock)




Ornithomimus fossils were first discovered in 1889 in Denver. They lived during the Late Cretaceous and are believed to be one of the fastest dinosaurs that ever existed. They were about six feet high and were about ten feet long from snout to tail.

Ornithomimus means “bird mimicry” in Greek, which refers to their similarities with today’s ostriches.

5. Giant Ground Sloth (Megalonyx)







Megalonyx searching tree

Photo credit: Tante_Spray. Stock Photo. (iStock)




Giant ground beasts roamed the earth about 35 million years ago, during the Pleistocene. These massive mammals were estimated to be about 10 feet long and weighed around 2200 pounds, according to NPS.

Giant Ground Sloth fossils were first found in 1797 in West Virginia, and were later discovered Hotels near Snowmass Village, Colorado.

“Like other ground sloths, the large clawed sloth was slow-moving and most likely lived alone. Like other ground sloths, Megalonyx probably used its large body size and claws to deter predators, “said NPS.

6. American Cheetah







Alert Cheetah Photo Credit: WLDavies (iStock).

Photo credit: WLDavies (iStock).




Sometimes referred to as a “fake cheetah”, the American cheetah is not actually related to the animal that roams the globe today, it was just extremely similar.

With a similar structure to the modern cheetah, it is believed that the American cheetah is the reason why Colorado is still home to the second fastest mammal on the planet – the hornhorn.

Full skeletal remains of this animal have been found on the continent, with fossils discovered in Colorado.

This animal roamed the area during the Pleistocene, about 12,000 years ago.

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