ISSUED: 9-91
Thomas G. Barnes, Department of Forestry

People either love or hate muskrats. If you prize the muskrat's fur, you will probably love the animal. Muskrats are the most valuable furbearing animal in this country in terms of numbers harvested.
Muskrats also hold a special place in the scientific and wildlife community because much of our early understanding of wild animal population dynamics was derived using the muskrat as an experimental animal.
Were it not for its name, the muskrat, or "marsh rabbit," would be excellent table fare. These semiaquatic furbearers are clean animals, and their flesh is highly palatable to humans and other wildlife, especially mink.
But if you are a pond owner, farmer or gardener plagued by their burrowing and feeding activities, you are likely to consider the muskrat a pest. The most serious conflicts between humans and muskrats occur when muskrats burrow into the banks of farm ponds, reservoirs and other earthen water-retaining structures. By tunneling into the dam, muskrats may cause a leak that is difficult to plug, resulting in pond drainage.
They can also become a nuisance to farmers and gardeners when they feed on crops or vegetables. Urban homeowners sometimes become terrified of muskrats because they mistake these clean, water-loving, plant-eating rodents for black or Norway rats. This is a common mistake because a muskrat, with its flattened, scaly, sparsely haired taft, resembles a large vole (to which it is closely related). This fear is unwarranted because muskrats are very clean animals and do not carry most of the diseases associated with rats and mice.

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 found throughout Kentucky wherever appropriate habitat is found. Appropriate habitat for muskrats is almost anywhere they can find a year-round supply of food and water. Muskrats spend most of their lives in aquatic habitats, such as ditches, streams, marshes, lakes, beaver ponds, mine pits, farm ponds or any wetland area.
The key component of muskrat habitat is slow-moving or non-flowing water that allows the growth of aquatic vegetation. Ideally, the water should be two to three feet deep. Cattails, bulrush, sedges and arrowhead (excellent for food and construction of houses) should be present around the bank.
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. Muskrats will sometimes eat animals, such as crayfish, mussels, turtles, frogs or fish, during periods of low food supply.
For shelter muskrats use bank burrows, "houses" built of aquatic plants and feeding huts.
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. Males will mate with as many females as possible, and copulation usually occurs underwater.
After a 28- to 29-day gestation period, 3 to 11 blind, naked and helpless muskrats are born. The young weigh about 3/4 ounces and measure four inches long. After one week, they are covered with a coarse gray-brown fur. Their eyes open when they are 14 to 16 days old.
The kits (young muskrats) are weaned by about the 24th day and fend for themselves by the end of their first month. The mother is ready to give birth again by this time. The first litter may stay in the nest; then the mother adds another nest chamber to accommodate the new litter.
Muskrats are mostly nocturnal and remain active all year. They are not great travellers, and the average home range is no larger than a 200-yard circle in optimal habitat. During the spring or fall and at times of crisis (flooding, drought, food shortages) muskrats can move considerable distances. It is during these crisis periods that muskrats are often seen on roads and travelling through urban subdivisions. At these times it is not uncommon to see a muskrat miles from the nearest source of water.
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. During a drought year, when overcrowding problems are magnified, muskrats are particularly susceptible to being eaten by other muskrats and a variety of other wildlife species. Muskrats are also susceptible to such diseases as tularemia and hemorrhagic disease, which can devastate an entire population.

Preventing & Controlling Muskrat Damage
Nonlethal methods of controlling muskrats exist, but they are expensive and may not be practical for many farm pond owners. If you are experiencing muskrat damage to the point where lethal control is necessary, consider using control methods during the winter. Muskrat pelts are in their best condition at this time of year, and the pelts may be sold to local furbuyers if you possess a valid Kentucky hunting and trapping permit.
Muskrats are considered furbearing animals in Kentucky. An open trapping season is established for the legal harvest of these animals, and they are subject to all applicable state laws and regulations. Consult the Kentucky Department of Fish and Wildlife Resources' trapping digest for information on removal of muskrats during the legal trapping season.
Landowners and tenants who live and work on the property are not required to have a Kentucky hunting and trapping license to remove muskrats that are causing damage to the property. After the animal has been destroyed, you must contact your local conservation officer for disposal of the carcass.
There are no repellents, fumigants or poisons registered for controlling muskrats in Kentucky. The most effective method of removing problem muskrats is trapping.

Nonlethal Control
The best solution for preventing muskrats from burrowing into dams is to properly construct the dam. Good dam construction should include the following:
1.A dam with an inner face having a slope of 3:1, outer face 2:1, eight feet wide at the top, three feet of freeboard and good grass cover with no grazing by livestock.
2.A spillway to prevent water from rising more than six inches on the dam.
3.Bank stabilization using riprap (large rocks), a 6 -to 12-inch layer of sand or pea gravel or 1 x 2 inch mesh wire laid against the bank. Banks should be stabilized at least two feet above and three feet under the normal surface water level.

Earthen dams can be protected by cutting a narrow trench down the center of the dam and filling it with concrete. The trench should extend three feet below the water and should be filled with concrete to one foot above the normal high-water level. This barrier will prevent muskrats from burrowing completely through the dam and causing a leak.
Contact your local Soil Conservation Service, fish and wildlife district biologist or Extension aquaculture or wildlife specialist for more information on proper pond construction.
Another method of reducing muskrat problems is to remove their habitat or food supply (cattail, burreed, rushes, sedges and arrowhead). Unfortunately, this also decreases cover for a variety of desirable fish and wildlife species.

Lethal Control
The most practical solution to muskrat problems is to remove individual animals. Muskrats can be shot in the early morning or at dusk with a .22 caliber rifle. However, the most effective and practical method of removing problem animals is trapping. Muskrats are among the easiest furbearers to trap.
The most efficient traps used to catch muskrats are the #1 or 1 1/2 steel leg-hold or the size 110 Conibear trap. Conibear traps are recommended because they kill the animal almost instantly. The "quick kill" action of the Conibear trap allows it to be set in shallow or deep water runways. Leg-hold traps must be set near deeper water. This is necessary to prevent escape because muskrats instinctively dive into the water when alarmed. Upon diving, the animals quickly drown.
To find suitable trapping areas, find "runs" along the bank where the muskrats go in and out of the den or out of the water to feed (Figure 2a - 2b). These trails are usually easy to see if the water is clear, or you can feel them underwater with your hands. Place the Conibear or leg-hold trap underwater as close to the den entrance or feeding trail as possible without restricting trap function. Be sure to stake the trap securely. If you are using a leg-hold trap, place it in two to three inches of water and stake it in deep water; otherwise, traps should be placed along the bank if a "quick drown" device is used. When the muskrat is caught, it will dive into deep water. The weight of the trap probably will be enough to drown a muskrat. However, using a "quick drown" device ensures a swift, painless death.
To build a "quick drown" device, securely wrap a piece of strong wire several feet long around a brick. Attach the other end to a stake near the trap site. Toss the brick into the water so the wire is taut. Secure the trap to the wire with an L-shaped piece of iron. This will allow the trap to be pulled down the wire while preventing it from sliding back up (Figure 2c).
Another effective way to trap muskrats in deep water is to construct an artificial feeding station. Trappers have captured as many as three muskrats in a single night per station and as many as 30 in a week using this technique. Cut a piece of plywood into a three-foot square. Attach five pieces of thick styrofoam to the bottom of this platform (Figure 3a, 3b, 3c, 3d). Place a leg-hold trap on each side of the platform, and nail the traps to the underside of the raft close to the center. The raft can be anchored to the shoreline or to the bottom of the pond using a concrete block. Bait the set by nailing an apple, carrot or corn cob to the center of the raft. Be sure to check the traps at least once a day. When you first begin trapping, consider checking the traps twice a day to maximize trapping efficiency.
Remove muskrats only if they are causing a problem because they are a valuable fur resource and an integral part of aquatic ecosystems.