Muskrat Love

Spring is in the air. Or it will be, if this snap of cold weather lets up...  Muskrats all around the country are dusting out their burrows, putting on their top hats, brushing out their tails, and getting ready for the breeding season that starts with spring break-up.  Cheery little rodents that they are, muskrats don't mate for life, and the breeding season will carry on, dare we say almost unabated, until sometime in August.  It takes about a month after mating to produce a litter, and a month after that, the mother is ready to give it another go, so a muskrat can produce a whole lot of little muskrats.

The muskrat is basically a large (very large!) fieldmouse, adapted to life in and around water. It has a rotund, paunchy appearance. The entire body, with the exception of the tail and feet, is covered with a rich, waterproof layer of fur. The short underfur is dense and silky, while the longer guard hairs are coarser and glossy. This has made it very desirable to the fur industry, where it continues to be popular today, contributing more to the total combined income of North American trappers than any other mammal.  It is also (so I am told) very tasty on the dinner table, with meat that is fine-grained, dark red, and tender. Better soaked overnight in salt water, to reduce the gaminess, it whips up into quite interesting dishes, such as Smothered Muskrat and Onions. No, I'm not making this up.

On my way to Parry Sound last weekend, I passed a big wetland area that was crowded with signs of muskrat residency.  Right by the road was a large muskrat house.  Muskrats build their houses in wet areas, making it harder for predators to reach them.  They don't use timber framing, however, unlike our own ExcaliBEAVER down in Damalot pond. In fact, muskrats are not closely related to beavers.  Muskrats start by first heaping plant material and mud to form a mound. A burrow is then dug into the mound from below the water level, and a chamber is fashioned at the core of the mound. Later, the walls of the lodge are reinforced from the outside with more plants and mud.  Cat-tails and bullrushes are favoured for the final exterior cladding.

Shortly after freeze-up, muskrats chew holes through the ice in bays and channels up to 90 m away from the lodge to create "push-ups." After an opening has been created, plant material and mud are used to make a roof over it, resulting in a miniature lodge. Typically there is just enough room for one muskrat in the push-up. It is used as a resting place during underwater forays, and as a feeding station.

There's one just visible behind the bushes directly above the main house in this picture.

The muskrat is well adapted to a semi-aquatic life style. Although fully functional on land, it has evolved characteristics that make it at home in the water. At three weeks of age it is a capable swimmer and diver. As an adult, it swims effortlessly and can do so for long periods of time. This ability is greatly facilitated by the buoyant qualities of the thick waterproof fur. When swimming on the surface, the muskrat tucks its front feet slightly forward against the upper chest while using the back feet in alternate strokes to propel the body. The tail is used at most as a rudder. When the muskrat is swimming under water, however, the sculling action of the tail probably provides as much propulsive force as do the hind feet.

Of all plants available in marshes, cattails are most preferred as a food item. However, muskrats appear to thrive equally well on a diet of bulrushes, horsetails, or pondweeds, the last two constituting the basis of the diet in northern latitudes. They also eat a variety of other plants, including sedges, wild rice, and willows.

During the winter a thick layer of ice restricts the muskrat to the interior of the lodge or burrow and the watery environment beneath the ice. The animal’s highly developed diving abilities and its use of push-ups become critical in procuring food under those conditions. It covers considerable distances under the ice searching for food. When the muskrat reaches a feeding area it chews off portions of plants and carries them to the nearest push-up, where it eats. This foraging activity under perhaps a metre of ice and snow, in ice-cold water and almost total darkness, is truly a remarkable feat.

When their normal food items are scarce or unavailable, and food of animal origin is abundant, muskrats are known to be highly carnivorous, or meat-eating. Under these circumstances muskrats most commonly consume animals such as fish, frogs, and clams. However, muskrats rarely do well on this type of diet and consuming such foods is generally taken to be evidence of hard times.

They can spend up to 15 minutes underwater, and can chew underwater with their mouth closed, thanks to specially adapted incisors and lips that can close behind those front teeth. Speaking of which, don't mess about with these guys -- they may not be all that big, but they are vicious fighters if provoked or cornered. Best to just let them be...