MANAGING MUSKRAT PROBLEMS IN KENTUCKY
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
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
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
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
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.
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
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.
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.