Dinosaurs That Lived in Iowa (And Where to See Fossils Today)

Written by Kyle Glatz
Updated: August 14, 2023
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Although it may be hard to imagine, Iowa was not always a land of rolling hills and plains. In the past, much of Iowa was underwater. The shallows seas, encroaching glaciers, and ongoing geological events did not help preserve fossils in this part of the country. That’s why we don’t know much about the dinosaurs that lived in Iowa.

However, we’ll take some time to dig into Iowa’s past and show you what type of dinosaurs lived in the area and what other prehistoric creatures roamed the land.

Infographic for 3 Dinosaurs That Lived in Iowa.
Besides two unknown species of Hadrosauridae, these three other dinosaurs lived in Iowa.

Let’s start by looking at the state fossil.

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What Is Iowa’s State Fossil?

Unlike many other states, Iowa does not have a state dinosaur. Iowa does not even have a state fossil. However, people have proposed various state fossils, and fossils of crinoids are gaining support. The crinoid was first proposed as the state fossil in 2018, but no firm plans to make the designation have been brought forth in recent years.

Crinoids are marine animals that look very similar to a plant. Fossils of these animals have been found throughout the state, reinforcing the fact that much of Iowa was once covered by bodies of water.

The creature could be named the state fossil in the future.

What Are Some Dinosaurs That Lived in Iowa?

Dinosaurs certainly lived in Iowa at some point in the Cretaceous Period. However, most of the sediments from the Mesozoic as a whole were not deposited. Most of the state was underwater and then glaciers came through the area later and disrupted existing deposits and brought additional material with them.

As a result, scientists have evidence of only one of the types of dinosaurs that lived in Iowa. However, they have fossil evidence from at least two species of the creature. Take a look at the information that paleontologists gathered about hadrosaurs in Iowa.

Hadrosauridae

hadrosaurus

Fossils of hadrosaurs have been found in Iowa.

©Bee_acg/Shutterstock.com

At least two hadrosaur specimens have been recovered in Iowa. A paleontologist named Brian Witzke recovered one in Guthrie County in 1982, but the fossilized bone material was too small to attribute to a specific dinosaur.

A man named Charlie Gillette recovered the first identifiable dinosaur bone, a vertebra, in 2000. This was also attributed to a hadrosaur.

Another likely hadrosaur fossil was found in Akron in the 1930s by John Holdefer. His daughter contacted the Geological Survey Bureau about the bone, which had been used as a doorstop. As it turns out, Mrs. Doris Michaelson had recovered a vertebra that was also from a large hadrosaur.

Members of Hadrosauridae were duck-billed dinosaurs. While some of them were small creatures, the largest vertebra recovered in the state could have belonged to a dinosaur that measured 30 feet long!

More evidence of dinosaurs that lived in Iowa is waiting to be discovered! For now, though, we only know about a few species that probably belonged to the Hadrosauridae family.

What Are Some Prehistoric Animals That Lived in Iowa?

While Iowa did not have many dinosaurs, the area was home to some interesting prehistoric animals. Some lived on dry land, and others lurked in the ancient seas that engulfed the area. Take a look at three of the most interesting prehistoric animals that lived in Iowa.

1. American Mastodon

Illustration of a Mastodon on a white background

Mastodons were approximately the size of modern

elephants

.

©Liliya Butenko/Shutterstock.com

American mastodons once wandered large swaths of prehistoric North America. These large mammals stood between 7 and 10 feet tall and weighed upwards of 10,000 to 12,000 pounds. They also had large, curved tusks and low-domed heads that would set them apart from the elephants that we know today.  

These creatures lived for millions of years before going extinct at some point about 11,000 to 10,000 years ago. They may have died off as a result of the changing climate or interactions with humans.

2. Woolly Mammoth

Mastodon vs Mammoth

Wooly mammoths went extinct around 3,900 years ago because of climate changes and being hunted.

©Dotted Yeti/Shutterstock.com

The woolly mammoth, Mammuthus primigenius, was another large mammal that lived in North America. They are known for their long, coarse, and thick hair which gave them their woolly appearance. The average woolly mammoth could grow between 9 and 11 feet tall and would weigh upwards of 12,000 pounds.

These animals were driven mostly to extinction about 10,000 years ago, probably as a result of the changing climate and humans hunting them. However, some populations of the woolly mammoth remained until roughly 3,900 years ago.  

3. Plesiosaur

Plesiosaurus

Plesiosaurus could have grown from 4 feet to 49 feet long based on fossil records.

©Lefteris Papaulakis/Shutterstock.com

The bones of plesiosaurs found in Iowa may not have been from animals that lived in the sea that once covered the state. Rather, they may have been reposited as a result of glacial advances in Iowa throughout history.

Either way, these large marine reptiles lived from 200 million years ago until 66 million years ago, dying out around the same time as the dinosaurs. They were not dinosaurs that lived in Iowa, though.

These creatures could have grown from 4 feet to 49 feet long based on fossil records. However, none of the fossils found in Iowa point to a plesiosaur in this area measuring 49 feet.

Where Can You See Fossils of Dinosaurs That Lived in Iowa?

Although you can’t find the fossils of dinosaurs that lived in Iowa in any museum, you can get access to some fossils of prehistoric creatures. The University of Iowa Museum of Natural History is the best place to start looking for ancient fossils.

Located in Macbride Hall on the Iowa City campus of the University of Iowa, the museum has several displays of ancient animals and depictions of life during the last ice age. However, if you want to gain access to real fossils, you can either look at digital collections or consult the University of Iowa Paleontology Repository where the fossils are held.

Contact the museum to get more information about the best way for you to see fossils, casts, or reconstructions of creatures that lived in ancient Iowa.

The photo featured at the top of this post is © Noiel/Shutterstock.com


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About the Author

Kyle Glatz is a writer at A-Z-Animals where his primary focus is on geography and mammals. Kyle has been writing for researching and writing about animals and numerous other topics for 10 years, and he holds a Bachelor's Degree in English and Education from Rowan University. A resident of New Jersey, Kyle enjoys reading, writing, and playing video games.

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