Muskrats are a large, semi-aquatic rodent that can be found in Chesapeake Bay wetlands. Muskrats prefer marshes where the water level remains fairly stable, between four and six feet deep. Their glossy pelts were once prized by the fur industry for the fur’s density and waterproof properties. In addition to muskrat’s waterproof fur, their rudder-like tails and webbed hind feet make them strong swimmers and divers. Muskrats are generally herbivores, feeding primarily on vegetation such as cattails and rushes. However, they will also feed on fish, frogs, freshwater clams and carrion on occasion. Muskrats often construct feeding platforms in the marsh to sit and eat food they have collected.

Known as Ondatra to the native Iroquois, their species epithet, zibethicus, is Latin for 'musky-odor,' referring to the scent that breeding males emit. Muskrats are brown with fine, pale fur at the throat. They have small ears and eyes, and hind feet that are larger than their forefeet. Muskrats grow to 16 to 24 inches and weigh about 4 pounds. Their lung capacity is extraordinary: individuals have been observed swimming underwater for up to 17 minutes, surfacing for 3 seconds, and then re-submerging for another 10 minutes!

Muskrats build dome-shaped lodges out of vegetation that contain nesting chambers, which they keep clean and free of droppings. These lodges also have one or more underwater entrances. They prefer to live alone but will occasionally share a lodge.

Muskrats can breed year round, but most breed in March-May. After breeding, gestation lasts about a month. Female muskrats can bear several litters a year, averaging 5 or 6 pups. The young can swim within 10 days; by the time they're one month old, they are independent and ejected from the nest.

Although most active at dusk, dawn or after nightfall, it’s not uncommon to spy muskrats sunning themselves on logs or swimming. Muskrats can be found throughout North America, except in particularly dry regions.