Thus there are two peaks in breeding activity separated by about 30 days. Evidence indicates that male muskrats remain at the same den with the female for several weeks. The young are weaned at about 1 month of age, but may stay with the parents for awhile longer. Second litters often overwinter in the same den with their parents. Muskrats' sexual maturity is reached at about 9 to 10 months of age.
Muskrats are basically herbivorous.
They feed mainly on aquatic plants such as the roots and stems of cattails, lilies, sedges, and grasses. They may occasionally eat some animal life such as mussels, shrimp, and small fish. Vegetation is collected and stored during the summer for winter use. Throughout the winter muskrats remain below the ice for great periods of time eating this stored food and submerged vegetation. Muskrats bring vegetation to these pushups and eat it there.