Muskrat facts for kids

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Muskrat
Temporal range: Recent
Conservation status
Scientific classification
Kingdom: Animalia
Class: Mammalia
Order: Rodentia
Superfamily: Muroidea
Family: Cricetidae
Subfamily: Arvicolinae
Tribe: Ondatrini
Genus: Ondatra
Binomial name
Ondatra zibethicus
(Linnaeus, 1766)
Muskrat range (native range in red, introduced range in green. Introduced range in South America not shown.)

Muskrats are rodents that live in freshwater and saltwater marshes, lakes, ponds, and streams. Muskrats often build dome-shaped houses in marshes. These houses, made of plants, protect the muskrat from predators, since the only entrance is underwater. Some muskrats live in burrows on the water banks. Muskrats are excellent swimmers but are slow on land.

Muskrats are native to North America, but have been brought to Europe and Asia, where they now live in the wild. Muskrats got their name because they have musk glands that produce a strong scent.

Description

An adult muskrat is about 40–70 cm (16–28 in) long, half of that is the tail, and weighs from 0.6–2 kg (1.3–4.4 lb). That is about four times the weight of the brown rat (Rattus norvegicus), though an adult muskrat is only slightly longer, and are almost certainly the largest and heaviest members of the diverse family Cricetidae, which includes all voles, lemmings, and most mice native to the Americas. Muskrats are much smaller than beavers (Castor canadensis), with which they often share their habitat.

Muskrat Skull
A muskrat skull

Muskrats are covered with short, thick fur, which is medium to dark brown or black in color, with the belly a bit lighter (countershaded); as the age increases, it turns a partly gray in color. The fur has two layers, which helps protect them from the cold water. They have long tails covered with scales rather than hair, and to aid them in swimming, are slightly flattened vertically, which is a shape that is unique to them. When they walk on land, their tails drag on the ground, which makes their tracks easy to recognize.

Muskrats spend most of their time in the water and are well suited for their semiaquatic life. They can swim under water for 12 to 17 minutes. Their bodies, like those of seals and whales, are less sensitive to the buildup of carbon dioxide than those of most other mammals. They can close off their ears to keep the water out. Their hind feet are semi-webbed, although in swimming, their tails are their main means of propulsion.

Distribution and ecology

Muskrat eating plant
A muskrat eating a plant, showing the long claws used for digging burrows

Muskrats are found over most of Canada and the United States and a small part of northern Mexico. They were introduced to Europe in the beginning of the 20th century and have become an invasive species in northwestern Europe. They mostly inhabit wetlands, areas in or near saline and freshwater wetlands, rivers, lakes, or ponds. They are not found in Florida, where the round-tailed muskrat, or Florida water rat (Neofiber alleni), fills their ecological niche.

Their populations naturally cycle; in areas where they become abundant, they are capable of removing much of the vegetation in wetlands. They are thought to play a major role in determining the vegetation of prairie wetlands in particular. They also selectively remove preferred plant species, thereby changing the abundance of plant species in many kinds of wetlands. Alligators are thought to be an important natural predator, and the absence of muskrats from Florida may in part be the result of alligator predation.

While much wetland habitat has been eliminated due to human activity, new muskrat habitat has been created by the construction of canals or irrigation channels, and the muskrat remains common and widespread. They are able to live alongside streams which contain the sulfurous water that drains away from coal mines. Fish and frogs perish in such streams, yet muskrats may thrive and occupy the wetlands.

Behavior

Muskrat lodge
A muskrat push-up

Muskrats normally live in groups consisting of a male and female pair and their young. During the spring, they often fight with other muskrats over territory and potential mates. Many are injured or killed in these fights.

Muskrat families build nests to protect themselves and their young from cold and predators. In streams, ponds, or lakes, muskrats burrow into the bank with an underwater entrance. These entrances are 6–8 in (15–20 cm) wide. In marshes, push-ups are constructed from vegetation and mud. These push-ups are up to 3 ft (91 cm) in height. In snowy areas, they keep the openings to their push-ups closed by plugging them with vegetation, which they replace every day. Some muskrat push-ups are swept away in spring floods and have to be replaced each year. Muskrats also build feeding platforms in wetlands. They help maintain open areas in marshes, which helps to provide habitat for aquatic birds.

Muskrats are most active at night or near dawn and dusk. They feed on cattail and other aquatic vegetation. They do not store food for the winter, but sometimes eat the insides of their push-ups. Plant materials compose about 95% of their diets, but they also eat small animals, such as freshwater mussels, frogs, crayfish, fish, and small turtles. Muskrats follow trails they make in swamps and ponds. When the water freezes, they continue to follow their trails under the ice.

Muskrat swimming Ottawa
Muskrat swimming, Rideau River, Ottawa

Muskrats provide an important food resource for many other animals, including mink, foxes, coyotes, wolves, lynx, bears, eagles, snakes, alligators, and large owls and hawks. Otters, snapping turtles, and large fish such as pike prey on baby muskrats. Caribou and elk sometimes feed on the vegetation which makes up muskrat push-ups during the winter when other food is scarce for them. In their introduced range in the former Soviet Union, the muskrat's greatest predator is the golden jackal.

Muskrats, like most rodents, are prolific breeders. Females can have two or three litters a year of six to eight young each. The babies are born small and hairless, and weigh only about 22 g (0.78 oz). In southern environments, young muskrats mature in six months, while in colder northern environments, it takes about a year. Muskrat populations appear to go through a regular pattern of rise and dramatic decline spread over a six- to 10-year period. Some other rodents, including famously the muskrat's close relatives the lemmings, go through the same type of population changes.

In human history

Muskrat (musquash) fur backs, jacket
Muskrat fur coat

Native Americans have long considered the muskrat to be a very important animal. Some predict winter snowfall levels by observing the size and timing of muskrat lodge construction.

In several Native American creation myths, the muskrat dives to the bottom of the primordial sea to bring up the mud from which the earth is created, after other animals have failed in the task.

Muskrats have sometimes been a food resource for North Americans.

Muskrat trap
Muskrat trap in the Netherlands

Muskrat fur is warm, becoming prime at the beginning of December in northern North America. In the early 20th century, the trapping of the animal for its fur became an important industry there. During that era, the fur was specially trimmed and dyed to be sold widely in the US as "Hudson seal" fur. Muskrats were introduced at that time to Europe as a fur resource, and spread throughout northern Europe and Asia.

In some European countries, such as Belgium, France, and the Netherlands, the muskrat is considered an invasive pest, as its burrowing damages the dikes and levees on which these low-lying countries depend for protection from flooding. In those countries, it is trapped, poisoned, and hunted to attempt to keep the population down. Muskrats also eat corn and other farm and garden crops growing near water bodies.

Royal Canadian Mounted Police winter hats are made from muskrat fur.



Muskrat Facts for Kids. Kiddle Encyclopedia.