Smithsonian Story

The groundhog’s extinct, horned relative

February 1, 2021
Small rodent fossil skeleton with pointy teeth and horns.

Ceratogaulus hatcheri, Smithsonian’s National Museum of Natural History

We don’t recommend pulling this little fella from its burrow to see if there’ll be six more weeks of winter. The small but fierce-looking Ceratogaulus hatcheri lived about 6 million years ago on the plains of what is now Kansas. It may have used those horns for self-defense.

The creature belongs to an extinct family of rodents called mylogaulids. Today, its closest living relative is the mountain beaver Aplodontia rufa. Both species reside with groundhogs, squirrels, prairie dogs, chipmunks and dormice in a group of rodents called the Sciuromorpha.

This specimen comes from the collection of the Smithsonian’s National Museum of Natural History.

Small fossil rodent skeleton in a storage container. A woman sits nearby with an open laptop.
Ceratogaulus hatcheri in fossil collections storage with Amanda Millhouse, vertebrate paleontology collections manager at the Smithsonian’s National Museum of Natural History