Muskrat is a considerably large rodent species with a thick coat that is colored in brown. The long tail lacks fur and is covered in scales. It's flattened vertically, acting as a rudder that allows the animal maneuver while in the water. Like the closely related beaver, muskrat lives near water. As a matter of fact, these two are the only mammals, constructing their dens directly in the water, where they live during the winter months and rear their offspring.
Muskrats are found in North America and Eurasia. North American population occurs from northern parts of the continent southwards to the Gulf coast, reaching the Mexican border. This species has been introduced in Eurasia, where it inhabits northern parts of the continent. Preferred habitat of this rodent is wet area with 4 - 6 feet of water. Muskrats are most commonly found in water bodies with constant water level such as marshes. In addition, they occur in ponds, lakes, and swamps.
Muskrats live in large social units, which are family groups. Each group has its own home range. Sometimes, when the territory is too small for the group, females will drive their young away. However, even in cases if fighting and cannibalism take place, the group doesn't disperse, but remains united. These rodents may be active at any time of the day with a peak period of activity, occurring from mid-afternoon to just after dusk. Although slow on land, muskrats are known to be excellent swimmers. Moreover, when diving, they are capable of remaining submerged for as long as 12 - 17 minutes at a time. They use musk as the primary form of communication as well as a warning for outsiders. Muskrats also associate through vocalizations, including squeaks and squeals. Quick temperature changes, combined with dry and hot weather negatively affect these animals.
Muskrats are primary herbivorous, their diet generally consists of cattails, sedges, rushes, water lilies, pond weeds and other aquatic vegetation. Depending on geographical location, they may also consume occasional clams, mussels, snails, crayfish, small fish and frogs.
Muskrats are polygynandrous (promiscuous) animals: this is when both males and females have multiple mates. Muskrats mate between March and August. During the mating season, males compete for their mating rights. Gestation period lasts for less that a month, yielding 5 - 10 young. Females may produce up to 3 litters per season, usually every month. Although newborn muskrats are blind, helpless and lack fur, they grow up very quickly. By one weeks old, their skin exhibits thin fur. By 2 weeks old, the young open their eyes. Muskrats begin venturing from the den at 2 - 3 weeks old, typically taking short trips before returning to the den. They are weaned at 3 weeks old, gaining independence at 6 weeks old. The age of sexual maturity is 1 year old.
Most of the threats to muskrats' population have to do with human activities. These animals are commonly trapped for their pelts that have high commercial value worldwide. In areas where these rodents are abundant, they negatively affect the environment, often causing habitat destruction. Thus, due to their burrowing habits, muskrats occasionally damage river banks. Furthermore, because of over-consumption, they reduce the amount of aquatic vegetation. For these and other reasons, muskrats hunted and poisoned throughout their range as a pest species.
According to IUCN, the Muskrat is abundant and widespread throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) and its numbers are stable.
Muskrats are a key prey species for local predators. In addition, these rodents largely affect the composition of local plant communities due to their grazing habit.