Muskrats live in wetlands: ponds, lakes, marshes and river banks. They are very good swimmers, using their tail for propulsion in the water. Although they resemble beavers, they are much smaller and lack beavers' distinctive flat leathery tails, having instead thinner tails.
The shape of their nostrils which allows muskrats to inhale remaining oxygen from recently exhaled breath. This allows for muskrats to swim under water for up to 15 minutes. The other adaptation has to do with how the muskrat got its name. Muskrats are named because of the musk glands located near the underside of their tail. These secretions are used to warn other muskrats when a territory is already occupied. Keeping other muskrats away cuts down on competition for food and mates and aids in the muskrat's survival.
Adult body length is usually between 25-40 cm long, with a strong, laterally compressed tail 20-25 cm long. The body is covered in thick, brown waterproof fur; the underparts are paler.