16 to 26 inches. Weight: 2 to 4
The most widespread of North American microtine (a
subfamily of mice) rodents. Marshes, edges of
ponds, lakes, streams, cattails, and rushes are
typical habitats. An essential habitat
ingredient is water of sufficient depth or velocity
to prevent freezing. The presence of
herbaceous vegetation, both aquatic and terrestrial,
is another essential ingredient. In general,
has very flexible habitat requirements and often
coexists in habitats used by beavers.
Primarily herbivorous and will eat virtually any
vegetable matter. Utilizes shoots, roots,
bulbs, and leaves of aquatic plants. Cattails
and bulrush are preferred foods. Will also
consume cultivated crops. On occasion will eat
animal matter. Food is stored in the burrow or
den and during winter may even eat part of its own
May be thought of as an overgrown subaquatic vole.
Mostly active at night but daytime activity is not
unusual. Often builds conspicuous dome-shaped
houses. Breeds during spring and summer.
5 or 6 young are born after a 22 to 30 gestation.
May have two or three litters per year.
Beaver - has large dorsally flattened scale over
The muskrat is a common and
valuable furbearer. Muskrats are widely distributed
throughout North America. This species can adapt to
a wide variety of climates. Muskrats are dependent
upon habitats including water. This species thrives
in many lakes, rivers, creeks, ponds, and marshes.
Muskrats can tolerate a certain amount of pollution
in water, and this important furbearer is often
found living within large cities.
The muskrat is classified as a rodent because of its
four incisor teeth in the front of the mouth. The two
upper and two lower incisors overlap, allowing them to
self-sharpen as they are used. Folds of skin behind the
incisors allow a submerged muskrat to cut vegetation
without getting water into its mouth. The size and
weight of muskrats varies with regions, and the quality
of food available. Southern muskrats average around two
pounds in weight, and weights of three and four pounds
are common for muskrats in the Northern states. Most
adult muskrats attain a length of 22-25 inches,
including the nearly hairless tail.
The muskrat has relatively small
front feet, with four major toes and small thumbs. Hind
feet are much larger, and partially webbed. The tail of
a muskrat is deeper than it is wide, and it tapers to a
blunt point at the end. The species use their tails as
an aid to swimming.
Muskrat fur is short and dense.
Colors are mostly browns with lighter shades of greys or
blondes on chest and stomach areas. The underfur traps
air, and prevents the skin of the muskrat from becoming
wet while it is in the water. Musk glands are
predominant beneath the skin on the lower abdomen of
male muskrats. These two glands become swollen during
the spring and produce a yellowish, musky smelling
Muskrats are one of our most prolific species. Adult
muskrats can have up to five litters in a year's time.
Muskrats in northern states seem to average about 2.5
litters a year. Muskrats in southern states often
average 3 litters. Litter sizes vary, and 5 or 6 kits
per litter is common. There is evidence that muskrat
populations may be somewhat cyclic. Muskrats produce
fewer litters when populations are dense and more
litters when populations are sparse. The quality and
abundance of food also affects the number of litters as
well as litter sizes.
Female muskrats born in the
spring are sometimes capable of raising their own litter
by late summer or early autumn. An average female
muskrat will raise about 15 or 16 young in a good year.
One female muskrat has been known to produce 46 young in
one year. The gestation period for muskrats is 29 days.
Muskrats are thought to have one mate during rearing
Muskrats are somewhat sociable with others of the same
species, but will often fight to the death as
populations become dense. Preferred foods include a
variety of vegetation, including roots, stems, and buds.
Muskrats often seek out undercut banks for protection
while feeding. Food is usually carried by this furbearer
by mouth, and eating takes place above the water level.
Muskrats are often active during the day, as well as
night, with peak activities near dawn and dusk. Muskrats
commonly stay underwater for five minutes while
searching for food and they are capable of holding their
breath underwater for 10-12 minutes. Territory sizes
vary according to population densities and the quality
of the habitat. These territories average about 200 feet
in diameter in marsh habitats, and slightly longer along
streams. Dispersals occur when the young are encouraged
to leave the dens. Most of the young muskrats do not
move further away than 200 feet in good habitats. Adult
muskrats sometimes disburse further distances,
particularly in the early spring before mating season
In many marshy areas muskrats
build dome shaped lodges of vegetation in the water,
similar to beaver lodges, but smaller in size, these
lodges have one or more underwater entrances, and
commonly house an entire family group. Smaller but
similar structures are known as "push-ups". These
push-ups usually serve a muskrat as a protected feeding
and resting area, especially after ice forms on the
water surface. Bank dens are common and these usually
have underwater entrances leading upwards to hollowed
out chambers in the bank above the waterline. Trails of
air bubbles can often be seen through thin ice. These
bubble trails are made by muskrats exhaling air as they
swim beneath the frozen surface.
Uncontrolled muskrat populations do cause damage to
private property and habitat. Hole digging activities
undermine earthen dams and dikes. Damages also occur to
irrigation canals and farm ponds. Large populations of
muskrats also cause "eat-outs". These areas are simply
overcropped by the feeding activities of the muskrats
and the loss of vegetation and resulting silting makes
the area less productive for other wildlife species as
well. Muskrat "eat-outs" often destroy the roots of the
vegetation, and it may take 15-20 years for the habitat
to return to its original capacity to serve wildlife.
Muskrats are an important prey
for a variety of wildlife, including mink, fox, coyotes,
hawks and owls.
One major disease is Errington's
disease. This serious virus can live in mud and infect
muskrats in areas that have been uninhabited by other
muskrats for as long as 5 years. Epidemics can and do
occur with this devastating disease. Muskrats are also
vulnerable to tularemia, and a variety of internal and
Few muskrats attain four years
Best Management Practices