By Miriam Turnbull
Brave souls who venture out on a hike through Springbrook’s wetlands on a chilly midwinter afternoon may catch a glimpse of this furry critter or lodges they have built amongst the cattails.
Muskrats are a small, water-dwelling mammal with webbed hind feet and a long, skinny tail.
They remain very active during the winter, making daily excursions out into the cold water to gather more food. Quite a tall order, as muskrats eat about one third of their weight every day.
Muskrats know the value of fresh veggies — unlike their cousin the beaver, who stockpiles winter rations.
So what kinds of food are muskrats looking for? They eat lots of aquatic plants like cattails, rushes and lilies, but they will also eat small fish, snails and clams. Although this food can be found in ponds, lakes and some small rivers, the muskrat’s preferred habitat is a marsh. Marshes not only provide excellent vegetation for eating, they also offer great materials for constructing lodges or burrows. They also have a fairly constant water level.
The home range of a muskrat is usually within 200 yards of its lodge or den. Muskrats communicate with each other using a secretion from their glands known as “musk.” This scent also acts as a warning for intruders within an established territory. Sometimes muskrats will also construct small feeding huts within their range – smaller, simpler versions of a lodge that allow them to eat without worrying about being eaten by a predator.
Muskrats are well built for life in the water, even when temperatures drop. Their dense fur traps a layer of warm air, and a layer of guard hairs repel water. Neither their tail nor their feet have this insulation, but muskrats are able to regulate their blood flow away from these extremities and minimize heat loss. Muskrats will also shiver both before and after diving into cold water.
A group of muskrats will also congregate together in a lodge to share warmth. Another winter challenge is dealing with limited oxygen under water and in the lodge. Muskrats can increase their red blood cell count, circulating more oxygen in their blood.
Springbrook’s marsh is great muskrat habitat. Next time you stop by, take a closer look at the cattails and see if you can spot lodges, tracks or other clues that the muskrat has been roaming around.
Miriam Turnbull is an interpretive naturalist at Springbrook Nature Center, 100 85th Ave. NW in Fridley. Director Mike Maher welcomes comments at [email protected] or 763-572-3589. Go to springbrooknaturecenter.org for more information.