Despite bearing a superficial resemblance to one another, muskrats and beavers are not closely related. Both belong to the order Rodentia, but the beaver is the only representative of the Castoridae family in North American, while the muskrat belongs to the Muridae (mouse) family. In fact, the muskrat is actually a highly specialized vole which has many features in common with the beaver because of the similar environment in which they live.