Muskrat
(Ondatra zibethicus)

Muskrats are much larger than lemmings or voles but are much smaller than beavers. Even though they are mainly aquatic, they are not related to beavers but are actually voles that have adapted to water life. The muskrat has the same general shape as a lemming or vole, with dark brown, dense, silky fur. Its tail is distinctive, naked, and roundish but is flattened side-to-side (like a Popsicle stick on edge) to act as a swimming "oar." The hind feet are partially webbed and have stiff hairs to help paddle along. Like beavers, muskrats are able to close their lips behind their front teeth so that they can chew under water.

Muskrats do not build dams, as beavers do, but they do build a variety of shelters. The main shelter is the lodge, which, unlike a beaver lodge, is constructed of tough aquatic vegetation such as cattails and bulrushes. It is smaller than a beaver lodge but can be large enough that geese will nest on it. Once the pile is complete, the muskrat will chew up from underneath and create one or more above-water chambers inside, much like beavers do. Muskrats also may build bank dens like beavers do. In summer, they construct separate feeding platforms of mud and plant material and, in winter, "push-ups" are vital to their survival. The muskrat will chew a hole through the ice and pile underwater vegetation on top of the hole. This little "push-up" den is large enough for one animal to rest and warm up. A few of these will be constructed about 100 ft. (33 m) from the main den to increase a muskrat's foraging distance as they do not store food for the winter like beavers do.

Their main diet is aquatic reeds and pondweeds (they target the underwater parts in winter), although frogs, fish, carrion and aquatic insects are also eaten.

In the summer muskrats tend to be solitary, but in winter a few may den together for heat efficiency. If you come across tracks in the mud, it is possible to distinguish between beaver and muskrat by the size of the prints and the tail marks. Beaver tracks are much larger and the marks from the flat tail may rub out part or all of the footprints. A muskrat's tracks are much smaller and its tail mark will show as a line, from the bottom "keel" of the tail. You can also see the web of the larger back feet for both animals.

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