The muskrat (Ondatra zibethicus) is an aquatic rodent closely related to voles and lemmings. Its name comes for the scent glands near its tail and the strong odor it uses to mark its territory. Muskrats are common throughout most of the United States and Canada and there is a significant introduced population in Europe.
Most muskrats are around two feet in length and weigh 2-4lbs, making them the largest species of the Arvicolinae subfamily. They live near or in saltwater and freshwater wetlands including marshes, rivers, lakes and ponds. Despite the loss of wetlands due to human habitation, muskrats have continued to thrive by building habitats in artificial irrigation canals and farm ponds.
Muskrats live in family groups consisting of a male and female pair and their young. They build lodges out of sticks, weeds and cattails in the shallow waters near wetland shores. The lodge usually extends back to the bank and is visible above the waterline but is only accessible via a 6-8 inch opening underwater. In winter months muskrats will often plug this opening daily to better insulate the lodge.
Muskrats are easily identifiable by their thick, short fur that ranges from dark brown to gray as the animal ages. Muskrats have long, vertically flat tails that are covered in scales. The shape of this tail along with webbed hind feet allows the muskrat to be an excellent swimmer. On land the muskrat drags its tail behind when it walks, making for easily-identifiable tracks. Its long claws also make it an excellent digger.
The omnivorous muskrat primarily feeds on cattails and other aquatic vegetation, though they will consume small sea life such as crayfish, frogs, turtles and mussels from time to time. Muskrats are primarily active near dawn and dusk, most likely to avoid predators. Birds of prey, wolves, coyotes, foxes, snakes and alligators all depend on the muskrat as a food source. In addition, muskrats are trapped and farmed all over the world for their fur and their meat.
Even though they are frequently preyed upon, muskrats continue to thrive because they are such prolific breeders. Females can give birth to up to three litters of eight young each year with all reaching full maturity within six months to a year. Because of this high birth rate, overpopulation can occur and muskrats are treated as pests in some European countries where they are not a native animal.
- Muskrats are capable of living in sulfurous streams near coal plants that are inhospitable to frogs and fish.
- Muskrats can hold their breath underwater for up to 17 minutes.
Missouri Department of Conservation