Giant Beaver Officially Named Minnesota State Fossil Following Science Museum Advocacy

St. Paul, MN – The Minnesota Legislature passed a bill Monday designating the Giant Beaver (Castoroides ohioensis) as the official state fossil of Minnesota, following a successful educational and legislative campaign led by the Science Museum of Minnesota. The bill now awaits signature by Governor Tim Walz.

The prehistoric Giant Beaver, which lived during the Pleistocene epoch until approximately 10,000 years ago, could grow to the size of a black bear — reaching lengths of up to 7.5 feet and weighing over 200 pounds. Fossil evidence of these impressive rodents has been discovered across Minnesota, providing important insights into the state's Ice Age history.

"The Giant Beaver represents an important chapter in Minnesota's natural heritage," said Alison Brown, President and CEO of the Science Museum of Minnesota. "By designating it as our state fossil, we celebrate our rich paleontological legacy and create new opportunities to educate Minnesotans about the fascinating prehistoric creatures that once called our state home."

The Science Museum of Minnesota played an instrumental role in advocating for the designation, launching a crowdsourced campaign in 2021 to select a state fossil candidate from a list of ancient organisms that had cultural and scientific significance for Minnesota. The Giant Beaver was the overwhelming choice. 

The museum has moved the state fossil initiative forward in three previous legislative sessions, but it failed to get it past requisite committees in both the state House and Senate. In this fourth session, with bipartisan support from Rep. Andrew Myers and Sen. Steve Cwodzinski, the bill was included in SF3045, and passed off the floors of both bodies on May 19, 2025. The bill incorporates translations for the Giant Beaver into both Dakota (Ċapa) and Ojibwe (Amik) as part of the official designation, unique in state fossil legislation. 

Support for this endeavor has come from a wide range of sources. The museum’s Indigenous Round Table and the Minnesota Indian Affairs Council provided crucial support in the form of letters to the legislature. Executive Director of the Bell Museum, Holly Menninger, lent further endorsement by providing enthusiastic testimony to the Senate State Government Committee in support of the designation. The museum partnered with nearby Bad Weather Brewing, who produced the Epoch Beaver Black IPA in order to spread awareness of the initiative. An active public engagement effort, especially through the museum’s paleontologists and government relations staff, focused on connecting people with their representatives to let them know Minnesota wants a state fossil. 

"Minnesota has a deep connection to beavers — from our modern ecosystems to our prehistoric past," said Alex Hastings, Fitzpatrick Chair of Paleontology at the Science Museum of Minnesota. "The Giant Beaver fossil specimens in our collection have long captivated visitors of all ages, making this massive Ice Age mammal the perfect symbol of our state's ancient natural history."

Minnesota becomes the 47th state to designate a fossil as an official state symbol. The Giant Beaver joins other Minnesota state symbols including the Loon (state bird), the Walleye (state fish), and the Lady Slipper (state flower). A photograph of the Giant Beaver, approved by the commissioner​ of natural resources, will be preserved and potentially displayed in the Office of the Secretary​ of State. 

The Science Museum of Minnesota will incorporate the new state fossil into its paleontology curriculum and outreach programs, helping students across the state connect with Minnesota's prehistoric past. Later in the year, merchandise will be available in the Explore Store to celebrate the Giant Beaver.