The muskrat is a medium-sized semiaquatic rodent, native to North America, and is an introduced specie in parts of Europe, Asia, and South America. The muskrat can be found in wetlands over a wide range of climates and habitats and it has important effects on the ecology of wetlands, and is also a resource of food and fur for humans. Although they are referred to as “rats” due to their medium-size and the fact that they have an omnivorous diet, they are not part of the “Rattus” genus. Muskrat fur is commercially used, especially for coats. The fur is often dyed to resemble more expensive furs and is sold under a variety of names. Also, muskrat gland secretions are used in the perfume industry. It has, however, became a serious pest in Europe, as the tunnels they create destroy canal banks and foundations.
Description and distribution of the muskrat
An adult muskrat is about 40–70 cm (16–28 in) long, half of that being its 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 is almost certainly the largest and heaviest member of the diverse Cricetidae family. They are covered with short, thick fur, medium to dark brown or even black in color, with two layers of fur that helps in the winter cold. They have long tails covered with scales rather than hair, that also aid them in swimming. The tails are slightly flattened vertically, which is a shape that is unique to the muskrats. When they walk on land, their tails drag on the ground, which makes their tracks easy to recognize. They do spend most of their time in water, as they are well suited for their semiaquatic life. Muskrats are capable of swimming under water for 12 to 17 minutes, as they can also close their ears to keep the water out, and they ale use their tails as their main mean of propulsion. They can chew food even under water without any problems.
They live in marshes or along ponds, lakes and rivers and are somewhat active throughout the day, but are particularly active when darkness comes. Muskrats build shelters like the beaver, from aquatic plants or roots of trees. For shelter, they will either dig tunnels or construct lodges, depending on the immediate habitat. In areas with steep banks or dams, muskrats will dig tunnels that begin underwater and lead up above the water level, where the chamber can remain dry. In other areas without steep walls or dams, muskrats build dome-shaped lodges out of nearby vegetation and mud. They can also build burrows that most of the times have two exits: one near the water and the other on land.
Muskrats 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. Species commonly eaten include cattail and yellow water lily. 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.
Breeding and dietary information
Muskrats, like most rodents, are prolific breeders. The breeding season of the muskrat begins in late winter and ends in September. A female can give birth up to 5 times per year, and to about 6-10 cubs at each birth. The cubs are born without fur, which appears only after about two weeks, which is when they also begin to swim. Muskrats live in large groups in a territory. As monogamous breeders, they continue to live with their mates and their younglings. They are though, very territorial, especially during breeding season, and if it gets too crowded, females with cubs leave because males can kill the little ones. Muskrats communicate by a secretion from their glands called musk. This scent also serves to warn intruders. They are capable of vocalizing by squeaks and squeals, however, they do have poorly developed senses of sight, hearing, and smell.
These rodents feed on a variety of plant foods including bulrush, lily, wild rice, clover, or willow. They gather food within their territories and carry it to feeding platforms on which they eat. These feeding platforms are flat, elevated piles of mud and vegetation, which muskrats construct outside of their living dens. When they build dens and outputs near orchards, they can also cause extreme damage because the can eat the roots of fruit trees and also store them in their dens. They can also harm crops of carrots, parsley, beets, onions and potatoes. Muskrats have specially evolved teeth that protrude ahead of the cheeks and lips that can close behind them, permitting them to chew on stems and roots under water “with their mouth closed”.
Plant materials make up 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 and when the water freezes, they continue to follow their trails under the ice. Muskrats eat an extreme amount of food, consuming an amount equal to one-third of their weight. On the other hand, 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.
However, when a muskrat builds a den, it can help a lot of other animals. Their dens can provide shelter space for snakes, turtles, toads and more. Raccoons are famous for housing in the muskrats’ old burrows. They also play important roles in certain ecological systems, as their eating and denning habits create the ideal flat nesting areas for certain birds.
Muskrats as pests
Although muskrats bring important contributions to natural aquatic systems, their dens can endanger structures that are found near water. There are known cases in which the presence of muskrats led to the destruction of bridges. Their number may increase to the point that an area is completely stripped of aquatic plants. After consuming all the plants, leave the area with nothing left behind and search for a different swelling place. This behavior destroys the roots of trees and together with the wind and water erosion actions, the banks are heavily affected.
Muskrats are carriers of some diseases that may be transmitted to humans and/or pets through a bite, drinking contaminated water, or coming into contact with muskrat flesh. The most serious illnesses include:
- tularemia – via ticks, bites, contact with infected flesh and contaminated water;
- leptospirosis – via contaminated, soil or contact with urine;
- giardiasis – via contaminated water, contact with/ingestion of waste or ingestion of infected flesh;
- rabies – via bites and contact with infected saliva.
The muskrat is also a vicious fighter when provoked. It stands its ground courageously if an escape route to deep water is not available and can inflict considerable damage on an attacker with its long incisors, or cutting teeth. The muskrat has long been hunted by humans, probably the major enemy or predator of this species and like many other wildlife species, the muskrat shows large fluctuations in numbers that follow what appears to be a regular pattern. In the case of the muskrat, numbers decrease drastically about every seven to 10 years. At such times, few or no muskrats can be found where two or three years earlier there had been thousands. These catastrophes are often blamed on predators or on over-trapping, so before applying any preventive measures against muskrats, read our related article where you can find more details regarding correct ways of repelling these pests away from your yard and preventing them from burrowing near your home, without causing too much damage to this specie.
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