Last spring I wrote in this column that I was very surprised to see a muskrat “house” in the cedar swamp, because the vernal pools there dry up completely in the summer. Later on in the summer when the ferns and shrubs were in full leaf, I decided the mound was just dead reeds and mud, though it was impossible to get near to check it out. I did not correct my “mistake” and it's just as well. I assumed that muskrats always live in ponds and marshes along water so they can always swim to their food and homes. However, I don't often see signs of them in the Adirondacks, so this is a reason to learn more about these native rodents.
Today when I went back to try to decide for sure what that two foot high pile is about, the pools were full and mostly frozen over with thin ice with a dusting of snow on top. There were tracks coming from near the mystery mound and they seem to be muskrat to judge by the track books. The animal was headed towards the hollow under a big white pine on the mainland. There are many holes through the raised hummocky areas where trees grow in the swamp too, six inches or so wide; one of them had fresh dead plant dumped next to it this spring and I had puzzled about what could have done that.
Though weighing as much as four pounds, muskrats, which secrete “musk” to mark territory and attract mates, have that ratty look, with a hairless tail that is flattened side to side, the better to steer with when swimming. They eat mostly plant matter, especially cattails, but any animal matter, dead or alive, that gets in their way will be devoured too. Those piles of mussel shells you see when canoeing are often left by muskrats feasting under the ice in air pockets, especially along shores.
A muskrat house is two to four feet high, with an underwater entrance (supposedly, but not when these vernal pools are dried up) and enough room inside for the animal and up to 11! young for a female. When the house freezes solid in winter it is pretty safe from predators, and in a pinch the inhabitants can eat the cattails and other vegetation they are made of, from the inside. (Beaver houses are much bigger and made of sticks and mud, neither of which are edible, but they can swim all winter to their under ice stash of bark covered sticks.)
Besides building houses, muskrats dig long tunnels into banks (and through man-made dams) but again the entrances should be underwater. They also sometimes use abandoned beaver houses, which must be a roomy delight for them. Or maybe like other mansions they are too drafty! In winter they make what are called “push-ups”; they break through thin ice from below and shove vegetation up through the hole into a mound big enough to be able to feed inside of, out of sight of their enemies. Muskrats are favored food for many predators including big fish, great horned owls, marsh hawks, and all our mammal carnivores. They are very feisty, however, and fight hard for their territory, mates and life.
I’ve had a secret cranberry island on a bog pond where for many years I have been able to pick a few quarts of beautiful big red berries in a small area. This year there was not a single berry, just droppings full of the tiny seeds! Nothing usually eats cranberries but this “rat” (not a true rat, I should admit) stole my berries. I hope it has a short memory.
What a life in winter, but their thick underfur keeps them dry and warm, not an unmitigated blessing because trappers covet that fur. As the animal can swim underwater for 17 minutes, it must be a long struggle before they drown. Are they just “furbearing game”? Or are they native wild animals, interesting and valuable in and for themselves, not just a pelt waiting to be removed? To me they are worthy of respect because of their ability to survive by their own wits often under very harsh conditions (or odd ones, such as the vernal pool swamp), against all odds.