Muskrats are excellent swimmers and can evade many predators by escaping into water or into their burrows and nests. They can stay submerged for up to 20 minutes and swim as fast as 5 kilometers (3.1 miles) per hour and can even swim backwards.
Muskrats follow trails they make in swamps and ponds. When the water freezes, they continue to follow their trails under the ice.
They find shelter in bank burrows and their distinctive nests. Bank burrows are tunnels excavated in a bank. The nests of the muskrats are formed by piles of vegetation placed on top of a good base, for example a tree stump, generally in 40 to 100 cm (15 to 40 inches) of water.
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 winter.
Outside the breeding season, muskrats are solitary except at times during the winter when several may share a den to conserve body heat. Home ranges vary in size from 30 to 350 meters (100 to 120 feet) in diameter. Individuals confine much of their activity to the area within 15 meters (50 feet) of the den.
