The common muskrat, Ondatra zibethicus (commonly known by its Abenaki native name musquah), is a fairly large rodent and is a native species to North America. It is found in marshes, quiet streams and ponds. They are found in most areas of the United States and are quite common in Connecticut and New England. The round-tailed muskrat, or Florida water rat, is found in swampy regions of Florida and southeast Georgia. It spends more time on land than the common muskrat. In 1905 the muskrat was introduced into Europe, and successfully spread through European countries. They are now common in northern Asia.
The muskrat is an aggressive fighter when provoked, and will stand its ground if no escape route is found. It can inflict considerable damage on an attacker. It is nevertheless often preyed upon by other species. The mink occupies much of the same habitat as the muskrat and can contribute in the high mortality of juveniles. The snapping turtle and the northern pike also prey on the muskrat. Muskrats are subject to predation by wolves, coyotes and foxes. They are also preyed upon by badgers, wolverines, raccoons, lynx and humans. They are trapped chiefly for their fur, although some communities eat their meat. In Belgium and Netherlands the muskrat is treated as a pest and is often referred to as a water rabbit.
The male muskrat marks his territory with musk, with mating occurring in spring and summer. Females have a gestation period of 30 days and give birth to several litters of six to eight young, with the last litter born in August. Muskrat populations go through a period of population rapid crashes and increases over a seven to ten year period. It is not clear what causes these crashes.
The muskrat is an aquatic rodent and lives in freshwater marshes, the marshy areas of lakes and slow moving streams. The water must be deep enough so that it will not freeze to the bottom during the winter, but shallow enough to permit growth of aquatic vegetation. They prefer areas that are plentiful in sedges, bulrushes, cattails or pond-weeds. They are mainly plant eaters but will feed on fish, frogs, mussels, crayfish and small turtles, especially during difficult times. Cattails are preferred, but they will also feed on bulrushes, horsetails, pond-weeds, wild rice, willows and sedges.
In many of the places where muskrats are found, mounds of plant material can be seen scattered among the cattails and bulrushes. These are the homes of the muskrat. Bulrushes and cattails, apart from being a food source, are used as building material in the construction of lodges and feeding stations, and also as shelter from winds and wave action.
The fall is spent building and reinforcing lodges for storing food and occupancy during winter. The lodge allows them to live in areas surrounded by water, offering protection from predators and giving them shelter from the weather. The muskrat builds a mound of plant material and mud, about 60 to 90 cm above the marshes. It digs a burrow into the mound from below the water level and makes a nest chamber within the mound. The walls of the lodge are then reinforced from the outside with more mud and plants.The lodges contain one chamber and one or two exit burrows. More complex lodges can have several separate chambers and exit holes.
Once the water surface has frozen over, a muskrat chews about two to three holes through the ice, about 90 m away from the lodge. Once a hole has been made, mud and plant material is used to make roof over it to form a miniature lodge. There is usually just enough room for one muskrat. The miniature lodge is used as a resting place during underwater forays and as a feeding station.
Muskrats also dig burrows into the banks of ponds and streams, with an entrance tunnel below the water line. This provides muskrats with a chance to escape from predators and with a food supply under the ice during the winter.
