Several small feeding huts that are similar to, but less complex than the lodges, may be constructed within the muskrat's territory. Here the animal will periodically feed while protected from predators and harsh weather. Muskrats are active throughout the year and, although mainly nocturnal, are sometimes seen during the day. They are susceptible to cold and wind and spend more time in their dens during the winter. Although several may share a lodge during the winter.
Muskrats are highly territorial and aggressive toward each other.
In fact, a female may kill newly-weaned young in an effort to drive them away before the arrival of a new litter. The muskrat's normal home range is usually within 200 yards of its den, although it may travel several miles over land in search of suitable habitat. With their webbed hind feet acting as paddles and their tail as a rudder, muskrats swim at a speed up to 3 miles per hour and can even swim backwards. The muskrat can give a warning slap with its tail, similar to the beaver, and remain submerged for as long as 15 minutes. Muskrats may modify wetland habitat making it more attractive to a wide variety of wildlife.