Damage:
Muskrats can damage pond liners, destroy plants around the ponds,
and can also dig dens in the sides of pond banks and dams.
Description:
The muskrat is another member of the rodent family. The muskrat looks
similar to the common rat but is larger. Muskrats very in total length
from 16"-25". There are 16 subspecies of muskrats in North America with
many different color variations. Muskrats in Iowa are typically light
brown to dark brown. The fur is medium length and quite dense. The tail
is naked, laterally compressed to aid in swimming and approximately the
same length as body.
Habitat:
Muskrats are found in conjunction with almost all permanent bodies of
water in Iowa. Muskrats are well adapted to an aquatic lifestyle and
are dependent upon it for protection from predators. Muskrats can be
found in the highest concentration in marshes. Populations as high as
35 muskrats per acre have been recorded on cattail marshes in Iowa.
Habits:
Muskrats have the annoying habit of making their dens in pond dams and
ditches. This is probably the single largest damage complaint
concerning muskrats. Muskrats prefer to build houses out of vegetation
if it is present in sufficient quantities and the water will not wash
it away. If no suitable place to construct houses exists, muskrats will
make dens in stream banks. Muskrats will often use slides, toilets and
feeding places repeatedly. They are nocturnal but may be active during
the day in the spring and fall. Muskrats tend to be less active during
nights with a full moon. They are most active during rainy nights.
Usually solitary the may live as part of a group in houses in the fall
and winter.
Reproduction:
Muskrats are very prolific. In Iowa females may have two or three
litters per year. Each litter commonly has four to seven young.
Breeding activity begins in March and peaks in May and June. Some
individuals may breed through September. As with most wildlife, adults
have fewer litters and fewer young per litter when the population is
above the carrying capacity. Individuals, especially males, become
quite territorial during peak breeding times. The gestation period is
about 30 days. The young become mature when approximately six months
old. Only 10%-20% of newborn muskrats live longer then one year with or
without trapping. The young are referred to as kits.
Food:
Muskrats are primarily herbivores, feeding upon the most abundant
vegetation. Smaller animals may also constitute a part of the muskrat's
diet if the preferred vegetation is not readily available. Cornfields
neighboring bodies of water are often used as feeding areas. Cattail,
bulrush, arrowhead, water lily, dry grasses, soybeans and corn are
favorite muskrat foods.
Sign:
The muskrat signs most easily identified are there droppings and "feed
beds." Feed beds are floating mats of vegetation where muskrats feed.
Signs where Muskrats have been digging to get roots of plants or eating
cattails may also be identified, Narrow mudslides and muskrat houses
are common where muskrat populations are high.
Predators:
People and mink are the major predators of muskrats, but raccoons,
great horned owls, coyotes, dogs and foxes also prey on them. Hawks,
cats, weasels, snapping turtles and some large fish may prey upon
muskrats and their young, but are only of minor importance in Iowa.
Diseases:
Tularemia, hemorrhagic fever, septicemia and coccidiosis are all known
to occur in muskrats.
Parasites:
Muskrats may be parasitized by mites, fleas, roundworms, flukes and
tape worms.