Muskrats live in swamps, ponds, rivers, streams, lakes, and agricultural drainage channels. They have also been known to venture into garden ponds, causing damage and even eating the local fish. Muskrats are excellent swimmers and can remain underwater for up to 20 minutes. In the summer, they reside in burrows with multiple tunnels leading up to a chamber. In the winter, they live in cone-shaped lodges—made of mud and plant debris—that they build in fall.

In the summer, muskrats eat leaves, stems, and parts of aquatic plants. In the winter, they consume the submerged parts of these plants. They will also eat mollusks, frogs, turtles, and salamanders on occasion. They generally feed at dusk or at night and remain active throughout the year.