The muskrat, known to some as musquash, marsh hare, or musk beaver, is a rodent that lives both in an out of the water along most Wisconsin waterways. The name comes from the musky odor that this small mammal gives off. The muskrat is an important furbearer for Wisconsin trappers, as these "rats" are harvested for their pelts which are then sold for money.
Muskrats are mostly nocturnal (active at night) and stay close to their lodges or burrows. The muskrat can look like a beaver with brown fur and partially webbed-hind feet, but look for its long (8-10 inch), narrow, flattened, hairless, rat-like tail. Muskrats are also about half the size of a beaver, measuring 18-25 inches long. They are excellent swimmers with their rudder-like tail, specially adapted eyes, nose and unique respiratory system. Muskrats can stay underwater for up to 15 minutes to find food or escape predators like mink, foxes, great-horned owls or hawks.
Like most rodents, muskrats have several young. They usually mate in the spring during March and April after they turn one years old. After mating, in about 30 days, four to eight young are born blind and hairless in a burrow, lodge, or an open raft of vegetation. Female muskrats have an average of two litters per year.
Muskrats eat mostly plants that grow along the water's edge like cattails, bulrushes, arrowhead, sweetflag, and reeds. If there are too many muskrats in an area, they can "eat out" all the plants. They also like clams, crayfish, frogs, rough fish and carrion (dead animals) when they can be found. Near farmland, muskrats may eat corn or other crops if aquatic plants are not available. In winter, they eat underwater roots, tubers, and pondweed.
If you see a tall mound of plant material sticking above the water, that is most likely a muskrat lodge. Muskrats build these in the fall where the banks gently slope to the water and the water is deep enough to not freeze to the bottom. They burrow upward from the bottom into the lodge where a room sits above the water level in the center of the pile with several "rooms" and tunnels. In winter, several muskrats can live in one "room." Their body heat keeps the "plunge hole," or underwater entrance, from freezing. Another smaller lodge may be built nearby to give them more space under the ice to search for food. They also like to build burrows or dens along steep banks or on golf courses with wetlands and can frustrate landowners with their digging.
Muskrats are fun to watch and easy to spot as they swim along busily looking for food. Muskrat tracks are also pretty easy to find. Keep your eyes open near water for webbed feet along with a long, skinny tail dragging along in the mud or sand. If you spot some tracks, look around. There's probably one of these adaptable little critters nearby.