Muskrats can be found in streams, ponds, lakes, marshes or wetlands. They feed on cattails and other aquatic food, as well as freshwater mussels, frogs, crayfish, fish, and small turtles. They are most active at night and do not hibernate over the winter but remain active year-round. Because of this, they have been known to eat the insides of their nests as a source of food in the winter.

Muskrats live in family groups consisting of one male and female and their young, called kits. Spring is filled with fights over territory and new mates, leaving many muskrats injured or killed in these fights. Muskrats build nests to protect themselves from cold and predators. If they are living in a stream, pond, or lake, they will burrow into the bank with an underwater entrance. In wetlands however, they build push-ups from vegetation and mud, up to 3 feet high. Muskrat females can have 2-3 liters of kits each year of 3-10 kits in each litter. Depending on the climate, they will mature in 6 months to a year. Muskrats communicate by musk or smell.