The piles are often many feet high. Waterfowl often sit and next on top of such dens. Muskrat also build canals through marshes as well. They are mostly nocturnal, but are occasionally seen durning the day. They feed on a variety of aquatic plants, some cultivated plants, and will take animals such as clams, snails, crayfish, frogs, and some reptiles.
Muskrat pelts are one of the most common furs on the market.