These areas are simply overcropped by the feeding activities of the muskrats and the loss of vegetation and resulting silting makes the area less productive for other wildlife species as well. Muskrats are an important prey for a variety of wildlife, including mink, fox, coyotes, hawks and owls. One major disease is Errington's disease. This serious virus can live in mud and infect muskrats in areas that have been uninhabited by other muskrats for as long as 5 years. Epidemics can and do occur with this devastating disease.
Muskrats are also vulnerable to tularemia, and a variety of internal and external parasites.
Few muskrats attain four years of age. Tracks Muskrats are dependent upon water, and the edges of streams, lakes and ponds often show evidence of activity. Track are commonly found in muddy areas and a distinctive dragging mark is often seen separating the tracks of the right and left feet.