Either of two semiaquatic, brown rodent species (family Cricetidae) native to marshes, shallow lakes, and streams of North America and introduced into Europe. The compact, heavy-bodied muskrat, or musquash (Ondatra zibethica), is about 12 in. (30 cm) long, not including the long, scaly, flat tail. The partially webbed hind feet have a stiff, bristly fringe. Anal sacs produce a musky secretion. The commercially valuable fur consists of long, stiff, glossy guard hairs overlying a dense, soft underfur. Muskrats live in either a burrow dug into the bank or a reed-and-rush mound built in the water. They eat sedges, reeds, roots, and an occasional aquatic animal. The round-tailed muskrat, or Florida water rat (Neofiber alleni), is smaller.