Water Workers

Muskrats (Ondatra zibethicus) live in DuPage County’s marshes, ponds, lakes, rivers and streams.

A muskrat has a stocky dark brown body, small eyes and ears, and webbed hind feet. When fully grown, it’s about 1 foot long and 2 to 4 pounds. Its 9-inch-long naked, scaly tail helps it move and steer in the water. Because its mouth can close behind its two large front teeth, it can forage underwater, where it can remain for over 10 minutes at a time.

They are nocturnal but remain active throughout the day in spring and summer, when they eat cattails, sedges, bulrush, water lilies, pondweed and other vegetation. Over winter, fish, crayfish and clams serve as sources for protein when vegetation is scarce.

The muskrat builds its house, known as a lodge, from cut aquatic plants that it piles on top of mud or roots in the water. The lodge is typically 4 to 6 feet wide with several underwater entryways. The muskrat keeps it clean, even defecating outside on nearby logs or rocks.

When marshes freeze in late fall, muskrats build mini lodges called “pushups.” After gnawing a hole in the ice, a muskrat pushes cattail reeds, other plants and mud up through the hole to form a protective dome, where the animal can feed and rest above the ice when it’s away from its main lodge.

Muskrats usually live alone, although several may live together during the breeding season. A female has two or three litters per year with three to six young per litter. She may have litters only a month apart, which means she may have two separate litters in separate nesting chambers in her lodge at the same time.