The Muskrat or Musquash, Ondatra zibethicus, is a large aquatic rodent native to North America (Alaska, Canada, United States, northern Mexico), and has been introduced in parts of Europe. In the Mid-Atlantic states it is nicknamed “˜Swamp Bunny’. Muskrats live in wetlands such as ponds, lakes, marshes, and river banks.
Adult muskrats weigh up to 3.75 pounds. Adult body length is usually between 9.75 and 15.75 inches long, with a strong, laterally compressed tail 8 to 10 inches long. The body is covered in thick, brown waterproof fur. The underside is lighter. They have partially webbed hind feet and small hand-like front feet. There are two unique adaptations of the muskrat as well. One is the shape of the nostrils. They look like the number “˜7′. This allows the muskrat to breathe in remaining oxygen from recently exhaled breath. The other unique feature is musk glands that are near the underside of the tail, which when secreted, warns other muskrats that a particular territory is already occupied.
Muskrats are very good swimmers, using their tail for propulsion in the water. Although they resemble beavers, they are much smaller and lack beavers’ distinctive flat leathery tails, having instead thinner tails.
Extensive burrow systems are dug in the ground adjacent to the water with an underwater entrance. In marshes, lodges are constructed from cattails and mud. They also build feeding platforms in wetlands. It is common to find Muskrats living in beaver lodges, too. Muskrats help maintain open areas in marshes, which helps to provide habitat for aquatic birds.
These animals are most active at night or near dawn and dusk. They feed on cattails and other aquatic vegetation, freshwater mussels, frogs, crayfish and small turtles. Their predators include mink, foxes, coyotes, wolves, lynx and large owls. They are also trapped for their fur and, in some communities, for their meat. Females have 2 to 3 litters of 6 to 8 young. Muskrat populations appear to go through a regular pattern of rise and dramatic decline spread over a 6 to 10 year period.
While much wetland habitat has been eliminated due to human activity, new muskrat habitat has been created by the construction of canals or irrigation channels and the muskrat remains common and wide-spread. They are able to live alongside streams which contain the sulphurous water that drains away from coal mines. Fish and frogs perish in such streams, yet muskrats may thrive and occupy the wetlands.