Late fall and its new ice is a time of busy work for muskrats

Newly built dome-shaped muskrat homes are numerous now on the edges of marshes, ponds and small lakes. I often see muskrats taking advantage of new ice sheets, using them as platforms on which to rest and eat on these cold late-autumn days. They are mainly vegetarians and bring various aquatic plant parts like tubers up for their picnics on the ice.

The muskrat is a little cousin of the beaver, weighing only 2 to 3 pounds and always found in or near water. The long, shiny guard hairs of its coat are a rich brown. Beneath these is a dense mass of thick underfur that is impervious to water. A muskrat has a long, scaly tail that is flat on the sides. It functions as a rudder. Partly webbed hind feet are used for propulsion. They can stay underwater for 10 minutes or longer without surfacing. Similar to beavers, muskrats have folds of skin inside their mouths that close behind the teeth, keeping water out while they cut and dig submerged plants.

Muskrats are more active by night than day. While they do not hibernate, they build houses shaped like miniature beaver lodges in preparation for winter. These houses are made of cattail and other smaller plants, plus mud, that they build into mounds. Then, like the beavers, they eat and dig out a chamber inside and an underwater entrance where they can enter and leave unobserved from shore. Muskrats may also burrow into banks and have their homes in tunnels above high water, but the entrance is always sufficiently below water level to be difficult to observe and below the winter ice level.

Jim Gilbert taught and worked as a naturalist for 50 years.