Muskrats remain active year-round and are, for the most part, nocturnal, so daytime sightings usually occur at dawn and dusk. In the Northeast, Muskrats generally start breeding in June; this early in the spring they are busy foraging for the young, tender, green leaves of cattail that are just beginning to appear. The stems, leaves, tubers, flowers and fruits of arrowhead, bulrush and water lilies are also among their favorite foods. To a lesser extent Muskrats also feed on snails, crayfish, frogs, turtles and fish.
Muskrats don’t eat while they swim. Rather, they often nip off vegetation and seek a sheltered spot where they rest on their haunches and tail while holding it with their front feet as they feed. Note the Muskrat’s long nails, used for digging burrows and dens in river and pond banks as well as for holding food.
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Cattails, sedges, rushes, water lilies and grasses make up the bulk of a Muskrat’s diet although these aquatic rodents have been known to occasionally dine on fish, crustaceans and freshwater clams.
Muskrats typically don’t eat their food where they find it – they usually bring it out to a feeding platform in the water, which provides them with some protection from predators. However, they make an exception for Bullhead Pond-lily flower buds (Nuphar variegata), also known as Spatterdock, which they often devour on the spot wherever they find them (see photo). Beavers, Porcupines (yes, Porcupines can swim), White-tailed Deer and waterfowl also dine on the leaves, rhizomes, buds, flowers and seeds of Bullhead Pond-lilies.
Female muskrats bear one to four litters a summer, with each litter consisting of one and 14 young (average is 6-7). The first litter is born in late April or early May and for the first two weeks they subsist solely on milk, but soon thereafter the parents start supplementing their offspring’s diet with vegetation.
When the young are about a month old, weaning will occur and the young will be out foraging for themselves. Until then, the parents work diligently bringing back the roots, stems, leaves and fruits of aquatic vegetation to their den where their young devour it. (Photo: muskrat bringing cattail leaves back to den)
Muskrats, or “rats,” as they’re sometimes derogatorily called, are semi-aquatic, mostly plant-eating rodents that live in ponds, streams, lakes and marshes. During the winter they seek shelter in lodges that they build out of grasses, reeds, cattails and sticks. Muskrat lodges are much smaller than Beaver lodges, which are constructed out of mud and sizable branches, sticks, stones and mud.
In the spring Muskrats often build nests by burrowing into a stream or pond bank, which they enter under water. Muskrats are also known to set up residence in active Beaver lodges. After dining on aquatic vegetation, the pictured Muskrat made a beeline for the beaver-occupied lodge nearby, and dove under as it approached it. Beavers and Muskrats tolerate each other’s presence in the same pond (and lodge) even though they both consume much of the same vegetation. Unlike Beavers, Muskrats supplement their diet of plants with frogs, crayfish, clams, snails, and fish. It may be that when cohabiting a lodge, they may help one another keep an eye out for predators. (Photo: Muskrat eating pond vegetation)
Muskrats are primarily herbivorous. The majority of their diet consists of the tubers, roots, stems, leaves and fruit of a variety of aquatic and terrestrial plants, particularly those of bulrush, cattail and arrowhead. A diet of high fiber is possible because of bacterial fermentation which takes place in their intestines. The digestion of many herbivores is aided by bacteria, but many plant-eaters are restricted in what they can eat because they are unable to change their diet without killing the bacteria. Muskrats, however, can and do consume large amounts of meat (frogs, fish, turtles, crayfish, etc.) and still maintain a healthy population of fiber-digesting bacteria. (Thanks to Jeannie Killam for photo op.)
Birthing time for Muskrats is late April/early May, so this year’s young are roughly a month old. Weaning begins now and young Muskrats, who have been able to swim since they were two weeks old, begin foraging for themselves. Parents continue to supplement their offspring’s diet during this transition. Although Muskrats are omnivores, the majority of their diet consists of the roots, stems, leaves and fruits of aquatic vegetation. However, when you’re feeding half a dozen offspring, you harvest whatever is available, including bedstraw (see photo).
For the most part, muskrats are herbivores. They consume with relish the leaves, stems and rhizomes of emergent aquatic plants such as cattails, bulrushes, sedges, horsetails, water lilies and arrowheads. Fish, frogs and invertebrates, including crayfish and clams, are also eaten to a lesser extent. Muskrats are voracious eaters (captive muskrats eat 25 – 30% of their weight daily). When their numbers are very high, muskrats can cause what is referred to as an “eat-out,” where they mow down everything in sight.
Like beavers, muskrats can close their upper lips behind their incisors in order to cut plants underwater without taking in water and choking. (photo: two young muskrats feeding on aquatic vegetation)