Muskrat
These large voles are commonly spotted in Colorado's still and slow-moving waters.
About This Species
The muskrat is an overgrown, semi-aquatic vole with dense under-fur and a nearly waterproof "overcoat." Their feet are webbed and fringed with stiff hairs. The ankles are rotated out so the hind feet work as paddles (but rather inefficient walking feet). The tail is flattened side-to-side and serves as a rudder.
More Information:
Physical Characteristics
The animals are dark brown in color, about 26 inches in length (of which the tail comprises nine inches) and weigh about two pounds.
Range
Muskrats live statewide in marshes, ponds and slow streams, often in areas dammed by beavers.
Habitat
Their lodges, made mostly of cattails and other aquatic plants, may be three feet high and six feet across. Feeding stations are similar but smaller. Inside the lodge is a nest chamber accessible only from below the water. Once inside the lodge, muskrats are safe from predators. Muskrats are managed as furbearers in Colorado.
Diet
Like other voles, these are runway builders and herbivores, eating mostly grasses, cattails, bulrushes and other marsh plants. They occasionally damage cornfields on flood plains, and their burrowing sometimes weakens ditch banks and levees.
Reproduction
Females breed in spring and summer and produce two or three litters of one to ten (the average is about six) young after a gestation period of about 30 days. The newborn young are blind, naked and vole-like, with round tails. Soon they acquire the muskrat’s proper flattened tail, and at two weeks can swim and dive.
Threats to Species
Muskrats are preyed on by coyotes, foxes and large owls. They also preyed on by mink and snapping turtles when they are inside their lodge. Floods also kill muskrats, and fluctuating water levels increase the risk of death.