Minnesota's New State Fossil Builds Community

The mounted skeleton of an actual juvenile Giant Beaver found in St Paul, Minnesota (right) next to a modern beaver skeleton (left). The Giant Beaver skeleton is on permanent display at the museum!

Recently, Minnesota adopted the Giant Beaver as its state fossil. Below is an interview with Alex Hastings, the Fitzpatrick Chair of Paleontology at the Science Museum of Minnesota.

AK: What is your position at the Science Museum of Minnesota? What are the roles you play in that position?

AH: I am the Fitzpatrick Chair of Paleontology, which means I run the Paleontology Department at the Science Museum of Minnesota. I get to set, guide and implement our larger strategies for research, collections management, and outreach. That entails a lot of things like grant-writing, permits for fieldwork, decisions on what does and does not come into the collection, public engagements with fossils, writing scientific publications, and so much more.

Table of fun fossils from the Science Museum of Minnesota brought out for the public release of the Epoch Beaver Black IPA at Bad Weather Brewing in St Paul, Minnesota. [people from left to right, Alex Hastings, Grace DeVault, Braden Nienaber, Nicole Dzenowski]

AK: What is the importance of a state fossil? Why do states pursue such a designation? What motivated you?

AH: To me, it was always about the educational value of state symbols. I have run into many people here in Minnesota that do not even realize Minnesota has fossils. Since many kids grow up learning their state bird, fish, etc, establishing a state fossil for Minnesota seemed like a good way to help people realize that there is a great natural heritage here that’s worth knowing about. Before Minnesota’s was finalized, there were 46 states in the U.S. that had already designated a fossil as a state symbol, so it was about time for Minnesota to get on board too!

AK: Tell us about the kinds of public support the Giant Beaver received? Why do you think it became the overwhelming favorite?

The Giant Beaver’s appearance at Beaver Fest at Carleton College (Northfield, Minnesota).

AH: When we started the Minnesota State Fossil Initiative, we came up with 8 great options that people could vote for. But before it started, we had an open call to see if the people would want anything else added to the list. The only real standout from that was the Giant Beaver. So we started an online vote in the Fall of 2021 and got more than 11,000 people to vote for their choice of 9 candidates for Minnesota State Fossil. The very clear winner was the Giant Beaver, beating out Ancient Bison, Scimitar-toothed Cat and even a shark! I think people love the fun quirkiness that is the living beaver and extend that to an adorable giant relative. I think there is a lot of fondness for beavers here, and the thought of one the size of a black bear is super cool.

AK: What was the political process for achieving state fossil designation for the Giant Beaver? What were the challenges? What was unexpected or meaningful for you in the process?

AH: In Minnesota, legislative sessions happen only January through May each year. So we started after the vote with the 2022 session. In order to become official, we needed bills in both the state Senate and the state House of Representatives. Each of those needed to get brought forward at a committee. From there, the bill could simply be passed forward, but as is usually the case, nearly all bills get rolled into larger groupings to ultimately get deliberated on then (hopefully) passed. That first year, we managed to get it to committee in the state Senate, where I gave testimony on the floor on its behalf, but we failed to get it in the state House of Representatives. We tried again the next two sessions, 2023 and 2024, but did not get it into committee in either house. We found out there was a representative who was not favorable to the choice of the Giant Beaver. One of the concerns she had was Indigenous support. I am very happy to say that after meeting with the Executive Director of the Minnesota Indian Affairs Council, we received a signed letter of support from them and through the process of engaging with Native cultures of Minnesota, incorporated translations for the Giant Beaver into Dakota (Ċapa) and Ojibwe (Amik). These names became an amendment to the official bill, and to my knowledge the first time Indigenous language has been used in the declaration of a state fossil. We also got a signed letter of support from every paleontologist with a Ph.D. in the state of Minnesota. We also underwent some intense outreach educational efforts, with our tiny department heading to different parts of the state several times a week for months. In 2025, we finally managed to get the bill to committee in the state House, and the bill quickly went forward in the state Senate as well. In each, the state fossil was rolled into a larger bill including many other things. At the end of the session in late May, it was all passed, and Minnesota officially got a state fossil with the governor’s signature on the whole thing! Woo Hoo!

Braden Nienaber inside the beaver exhibit at the Minnesota Zoo.

I honestly did not think it would be

The paleo team from SMM at the Bemidji State University men’s hockey game. [people from left to right, Nicole Dzenowski, Alex Hastings, Grace DeVault - photo credit: M. Rios-Sanchez]

this difficult. Other states typically have a passionate third grader with a connection to local government bring it forward, and it passes with little to no issue. After four years of hard effort, I have gotten way more familiar with the process, both good and bad, and the most meaningful part for me has been all the support we’ve gotten through this experience. We’ve gotten to see and do things we never thought we would. Two of our team even got to pet the actual beavers at the Minnesota Zoo! We tabled at everything from local schools to breweries to a Bemidji State University hockey game (Go Beavers!). We even had a special beer made (Epoch Beaver Black IPA) by our friends at Bad Weather Brewing to help spread the word. It has been a rewarding and challenging experience, and I am so glad we finally did it.

AK: What are the differences in species characteristics between the Giant Beaver (Castoroides ohioensis) and the North American Beaver (Castor canadensis)? One of the main divergences seems to be the shape of the tail. The Giant Beaver has a tail that looks more like a tail a muskrat would have. The paddle tail hadn't evolved yet. Can you describe what drove that evolution? Next to its teeth, a beaver's paddle tail is its iconic feature. Can you say more about why this part of a beaver's anatomy would be so different in Castoroides ohioensis?

AH: Obviously size is a big one, but there are also some differences in the teeth. Giant Beavers have this sort of ribbing along the external edge of their big incisors, which is really distinct. That’s how the partial incisor from Freeborn County got identified as Giant Beaver. The rest gets a bit more subtle.

I would actually argue that we do not really know if the Giant Beaver had a flat tail or not. The bones themselves are similar enough across large rodents that there isn’t a way to tell just by looking at them which style of tail the Giant Beaver had. That big flat tail of the modern beaver is all soft tissue. I think someone could figure it out, but it’d likely be a very involved study trying to find subtle indications or proportions on the bone that would align it to the more beaver- or muskrat-style tail. It would likely also involve high-detail digital anatomical study. However, until that work is done, we need something to go with when making artistic reconstructions and the muskrat tail is as good an option as any. It is a bit more in line with a chemistry study that found that the Giant Beaver had a diet more similar to muskrats than to modern beavers. As for the evolution of a flat tail, we can see all the many uses that modern beavers can put that tail toward. The biggest one seems to be alerting other beavers to danger and helping ward off potential threats by slapping it against the water. It’s also useful for stability while they carry things in their front arms, like food or dam-building material. The flat tail of beavers seems to have been a big part of their success story and why they became so widespread. They also existed alongside the Giant Beaver and their ability to adapt to their environments to suit their needs is also likely a very big reason why they survived to modern times, but their giant cousin did not.