Cricetidae (New World rats and mice) in the order Rodentia

This medium-sized mammal has short front legs with small feet, stronger hind legs with large feet, and a vertically flattened, scaly tail that is slightly shorter than the combined length of head and body. The hind feet are partially webbed. The back is blackish brown and the sides are lighter brown with a reddish tinge; the underparts are still lighter, shading to white on the throat. Their musk glands produce a mild and inoffensive odor.

Total length: 16–25 inches; tail length: 7–11 inches; weight: 1½–4 pounds.
Habitat and conservation: 
Muskrats are semiaquatic, living in marshes, sloughs, streams, rivers, ponds and lakes. Here they dig homes in a stream or pond bank or build large houses out of vegetation in the shallow water. The nest, or den, is reached by means of a tunnel that usually opens under water. In Missouri, the most important management measure is to regulate the harvest. Where muskrats are too numerous, trapping is the most satisfactory means of control.
In marshy areas, muskrats eat rootstocks and stems of cattail and three-square bulrush and the seeds of lotus. In other areas of the state, white clover, corn and bluegrass are preferred. Muskrats living along Ozark streams eat freshwater clams, snails, crayfish, fish, frogs and aquatic plants.
Distribution in Missouri: 
Life cycle: 
Breeding occurs from late winter to mid-September, with 3 peaks, at the ends of March, April and May. Pregnancy averages 28 days; usually 2 or 3 litters are produced annually by a female. The litters usually contain 4–7 young, which are born blind and nearly helpless and naked. After a week they have coarse gray-brown fur. In another week, their eyes open and they start to swim and dive. At 3 to 4 weeks of age they are weaned. Most breed for the first time in the following spring.
Human connections: 
Muskrat pelts are common on the commercial market; almost all is used in the manufacture of women's coats. The fur is durable; the skin makes strong leather and takes dye well. The flesh tastes gamey. Dried musk is used in making perfumes and in preparing scent for trapping animals.
Ecosystem connections: 
As an omnivore, the muskrat helps control populations of both the plants and the small animals they consume. The dens, mounds, tunnels and canals they construct become habitat for other organisms to use. Muskrats and their young are preyed upon by many predators.