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Nature Notes: Muskrat

If you enjoy this article, you’re sure to love Ed Robinson’s 2018 book, Nature Notes from Maine, which includes wildlife stories, stunning photographs and ink drawings. Click here for details.

By Ed Robinson

If you are 50 or older, you surely remember a wonderful little song from 1976 about two lovers named Susie and Sam. According to the song, they courted by candlelight, doing the shimmy, whirling a tango and jingling a jangle. The song “Muskrat Love” was recorded by Captain and Tennille and reached number two on one of the pop charts. It’s not clear if Captain and Tennille ever saw any muskrats in love, but their song was perfect for dancing with your sweetie!

Muskrat (Photo by Ira Sha, iStock)

As with most other fictional accounts of wildlife, the song took great liberties with the lifestyles of muskrats – I have never seen muskrats dancing or singing. But who knows what goes on in their small dens during the winter months?! Since muskrats are high on the list of desirable foods for many predator species, the small rodents need to keep producing large numbers of offspring to sustain their population.

First, the muskrat is not a rat, although it is one of the larger members of the rodent tribe. Their closest relatives may be voles and lemmings. Like many other rodents, the muskrat has small eyes and relatively short ears that can be closed when underwater. The two-layered fur is normally mid to dark brown but in some cases may vary from black to light gray. The scientific name Ondatra zibethicus derives from Native American words for “red,” referring to the color of the muskrat’s fur, and for “musk,” the oily scent produced by glands near the muskrat’s anus used for marking territory. Since an adult muskrat can reach 24 inches in length including the long, scaly tail and up to four pounds in weight, let’s be glad that rats cannot match them in size.

Muskrats are aquatic creatures, living in wetlands, ponds, lakes and slow-moving streams or rivers. Their diet is varied but almost totally vegetarian, including pondweed, cattails, sedges, arrowhead, bullrushes and water lilies. If normal food supplies are tight, muskrats will consume agricultural crops such as clover, corn and alfalfa. They have also been observed eating small shellfish, snails, frogs and salamanders. Like the beaver, the muskrat has four prominent incisor teeth, two up and two down, that are positioned to sharpen each other as the animal feeds. The teeth extend well back into their skull and gradually move forward as the leading edge of the teeth are worn down over time.

The female can produce up to eight kits in each litter, and two litters per year are common in our northern climate (in warmer southern states three litters are possible). At birth the kits weigh just one ounce and are helpless. They are sustained on their mother’s milk for about one month but then they are strong enough to leave the den and consume green vegetation. Juveniles may live with their parents for several months or move a few hundred yards away to set up their own homes. Staying in dens as family groups over the winter allows them to maintain sufficient body temperatures to survive harsh northern winters.

If you sit quietly on the shore or move slowly in a canoe through appropriate habitat early and late in the day you may be lucky enough to see muskrats at work. They are excellent swimmers with large partially-webbed hind feet and they use their tails for propulsion and as rudders. On occasion they will swim with their tails raised above the water.

Their small front feet are used primarily for feeding and digging, either to find tasty plant roots or to build tunnels, channels and dens. If you look closely, you are likely to notice floating pieces of vegetation that have been partially eaten by the muskrats. They sometimes create small platforms of vegetation and mud where the muskrat can sit and eat, while absorbing the sun’s rays on a cold day. When threatened they are capable of swimming long distances under water and remaining submerged up to 15 minutes.

Like the much larger beaver, the muskrat creates living quarters on or near the water, with underwater entrances for protection from land-based predators. If steep banks are soft enough for digging, the muskrat will dig tunnels in the earth about six inches in diameter up toward a larger living chamber above the high-water mark. In shallow, open water the muskrat will build a lodge using vegetative matter and mud but not the branches and limbs used by the much stronger beaver. These lodges may extend two to three feet above the water but are far smaller than a fully-developed beaver lodge. Muskrats will also make small clusters of vegetation called “pushups” where they can sit and rest without being exposed to air borne predators.

Muskrats are mostly nocturnal since they are safer in the dark. In soft sand or mud you may find evidence of their movements in their foot prints, often with a drag mark of the tail or mud slides they use to move to and from land. In winter, you may find bubbles under clear ice, an indicator that muskrats may be active in the water below. Muskrats are normally docile creatures who go about their business of feeding, building homes and breeding, but they can be aggressive in fighting over territory or breeding rights. They are not well equipped for defense against predators so they are often targeted by mink, otters, raccoons, bobcats, foxes, coyotes, wolves, bears and larger raptors. In the water they may fall prey to snakes, turtles and large fish.

Historically muskrats have been one of the most common fur bearers caught for their pelts, with the fur finding its way into coats, hats, gloves, blankets and wraps. In periods of high fur demand, muskrat pelts fetched as much as $25 each, but in recent years they command only about $3 each. Since muskrats can carry diseases such as tularemia and giardia, they should be handled with care by humans. In some circles roast or baked muskrat is a popular dish but it should be well cooked in view of the diseases they may harbor.

Muskrats play an important role in the wetland areas where they thrive. By consuming large amounts of aquatic vegetation, they can create openings needed for waterfowl and other wildlife. Not only are muskrats an important source of food for many creatures, but their lodges and platforms are often used by other species for resting and nesting. Too many muskrats can be a problem, however, since a surge in their population can result in excess consumption of vegetation in a given area. Their tunnels and dens may cause erosion in dikes and berms, undermining of retaining walls, and injuries for large animals that step into the broken ground.

Hmmm, I wonder how long it will take for me to get that tune out of my head….

October 2020