Animal Facts and Biology

Muskrats (Ondatra zibethica) are one of the largest rodents in Kentucky. They are stocky animals with broad heads and short legs. Their pelts consist of soft, thick underfur with long, glossy, dark-red to dusky-brown guard hairs. Their front feet are not webbed. They have four sharp-clawed toes and a small thumb on each front foot. Their large hind feet are partially webbed, with stiff hairs along the toes. Adult muskrats measure 16 to 25 inches in length and weigh between 1 3/4 and 4 pounds. Their tails measure 7 to 11 inches long.

Muskrats get their name from the pair of musk glands located at the base of their tails. These glands are used during the breeding season when musk is secreted on logs or other areas around houses, bank dens or trails on the bank to mark the area.

Muskrats are vegetarians and relish cattails, bulrush, smartweed, duck potato, horsetail, water lily, sedges, young willow sprouts and pickerel weed. Muskrats will eat almost any aquatic vegetation, including the bulbs, roots, tubers, stems and leaves of numerous wetland plants. They occasionally eat corn, soybeans, grain sorghum and small grains. For shelter muskrats use bank burrows, "houses" built of aquatic plants and feeding huts.

Muskrat lodge

A muskrat can also live in a lodge like this one.

Most muskrats in Kentucky live in burrows in the bank of a stream or pond. The entrance to the burrow is usually a four- to six-inch diameter hole located six to eight inches below the surface of the water. This opens up to a lateral burrow which may be as long as 15 feet. At the end of the burrow is a raised, dry nest chamber. Some muskrats in Kentucky live in cone-shaped "houses" that measure up to 2 3/4 yards in diameter. The height of these houses varies, and each house will have one or two separate raised chambers.

Feeding huts are platforms of marsh vegetation where the muskrat brings food to eat. These huts are usually circular and smaller than houses. Muskrats are prolific breeders and can produce an entire generation in about 30 to 60 days under optimal conditions. In Kentucky, muskrats have three to four young per litter and may have three or more litters a year. Muskrats breed year round in more southerly latitudes, but the breeding season in Kentucky usually runs from March through October, peaking in March through June. Females will have multiple litters each year and range in size from 3-11 pups.

Muskrats are mostly nocturnal and remain active all year. They are not great travelers, and the average home range is no larger than a 200-yard circle in optimal habitat. Muskrats are eaten by a host of predators, including hawks, owls, raccoons, mink, fox, coyote and even largemouth bass and snapping turtles. Muskrats also prey upon other muskrats. During periods of overcrowding, other muskrats may kill entire muskrat litters. Muskrats are also susceptible to such diseases as tularemia and hemorrhagic disease, which can devastate an entire population.