3/17/2017 7:25:00 AM The lake where you live Meet the muskrat
Ted Rulseh Columnist
It's been a long time since I have seen a clump of green foliage slowly swimming its way across the surface of Birch Lake.
The foliage of course was being carried in the jaws of a muskrat, and we don't seem to have those critters on our lake anymore. Or maybe it's just that they are somewhat nocturnal and I haven't been looking at the right times.
You can easily tell even in winter if you have muskrats on your lake. You'll see a conical mound of brown vegetation sticking up above the ice. They build these lodges in fall in spots where the bank slopes into the water and it's deep enough so the ice won't form all the way to the bottom.
The muskrats enter the lodge from below; inside there's a room in the center, high and dry, with tunnels connecting to other rooms. In winter, one room may be home to several muskrats. Their body heat keeps the underwater entrance from freezing shut. And that's a good thing, because muskrats don't hibernate and they don't store food in their houses. They have to feed actively all winter long, foraging under the ice for pondweed and for roots and tubers in the sediment.
In other seasons, muskrats feed on water's-edge plants like arrowhead, pickerel weed, rushes, reeds and - their favorite - cattails. Especially if for some reason plant life is scarce, they'll eat creatures like frogs and crayfish, and sometimes carrion. When they find food, they usually carry it to a protected area like an undercut bank before eating.
Muskrats are well adapted for gnawing plant material. The upper and lower pairs of cutting teeth (incisors) continually sharpen against each other.
A bit slow and awkward on land, muskrats are skilled swimmers if not especially speedy (topping out at around 3 miles per hour). They paddle with partly webbed hind feet and use their narrow, laterally flattened and hairless tail as a rudder. When swimming, they can seal off their ears and nose to keep the water out. They can stay underwater for as long as 15 to 20 minutes to forage for food or get away from an enemy, like a fox, hawk or owl.
Muskrats tend to stay fairly close to their lodges or to the burrows they dig in banks. At first glance, given their brown color, they can be mistaken for beavers, but of course they are about half the size, about 18 to 24 inches long including eight to 10 inches of tail. Their web-footed tracks and tail drag marks in the mud along shore are distinctive.
So, why do we call these critters muskrats? It's because they have musk glands under the skin at the base of the tail; these secrete musk on logs and around lodges and banks during the breeding season. And speaking of breeding, they are prolific. A female in our latitude will usually produce two litters of four to eight young after a gestation of about one month.
That could mean a lot of "swimming foliage."
Ted Rulseh, who lives on Birch Lake in Harshaw, is the author of the "The Lake Where You Live," a blog where readers can learn about the lakes they love - the history, geology, biology, chemistry, physics, magic, charm. Visit lakewhereyoulive.blogspot.com. Ted may be reached at firstname.lastname@example.org.