Muskrats Are Fat Little Rodents With a Signature Smell

First, muskrats (Ondatra zibethicus) are often mistaken for their rodent cousins, beavers, who are also semi-aquatic. However, beavers are larger than muskrats and their tails are flat like a paddle, while muskrats have vertically flattened tails that act as rudders when they swim.

"Beavers and muskrats are both gnawing rodents, but beavers build dams that result in ponds where muskrats can live," explains Margaret Gillespie, a naturalist with Squam Lakes Natural Science Center in Holderness, New Hampshire.

Muskrats are stout little critters, with thick fur that can range in color from red to brown to black; it's also lighter in color on the throat and tummy areas. A short stiff underfur provides them with much needed insulation and buoyancy. They can weigh anywhere from 1 to 6 pounds (0.45 to 2.7 kilograms), and their sparsely haired tails are flat on both sides and comprise as much as 10 inches (25 centimeters) of their total 12- to 24-inch (30- to 61-centimeters) length.

Swimming is their forte and they are fast; they can paddle up to 3 miles per hour (5 kilometers per hour). Their large hind, partially webbed feet act as oars. They're also able to stay underwater without taking a breath for up to 20 minutes. You can find them in any type of water, including ponds and lakes, but they prefer marshes with lots of vegetation and a steady depth of at least 4 to 6 feet (1.2 to 1.8 meters) of water. Their aquatic skills make up for their poor vision, hearing and sense of smell.

Muskrats are native to Baja, California, most of North America south of the tundra, from Alaska to Newfoundland into the southern United States — excluding coastal Florida, Georgia and South Carolina.

Marshes provide muskrats a full menu of food, which is good because they eat about a third of their body weight every day! They typically pig out on roots, stalks and cattails with a few frogs and insects thrown in. In winter, they swim below surface ice to get to roots, because, unlike beavers, they prefer food fresh and don't store it away for the cold winter months. Fur mouth flaps behind their teeth keep water from getting in while they are eating.

Muskrats use mud and vegetation to build dome-shaped "lodges" on tree stumps or anything that is partially submerged in water. Lodges can be up to 3 feet (0.9 meters) tall and contain dry chambers. Each lodge has at least one underwater entrance to a tunnel. Tunnels extend for up to 15 feet (4.5 meters) and are burrowed by muskrats starting from a slanted embankment. To stay warm in the winter, muskrats huddle together in chambers.

Muskrats like to stay in large family groups within their own territories. Female muskrats are prolific child bearers and have one to three litters of five or six "kits" every year. They nest in chambers inside their lodges and have a gestation period of about a month.

Kits are born blind but are quick learners; they can swim at about 21 days after birth. Muskrat moms believe in tough love and will kick their offspring out of the lodge when they hit their 1-month birthday or if it just gets too crowded. They can live as long as 10 years in captivity and three or four years in the wild, which explains the truncated pregnancy and childhood.

Muskrats are active all the time but prefer to sleep in and are most active from midafternoon through dusk. Quick changes in temperature aren't good for them, especially when it's hot and dry, but their homes and burrows protect them from the elements.

Not everyone or every animal considers muskrats harmless little creatures. Luckily, their swimming skills usually allow them to escape and dive under water or hide in lodges. They're slow on land, which is why they stick to the water so much.

Muskrat life isn't one big swimming party among the cattails though. Their many predators include raccoons, owls, hawks, fox, mink, otters and bald eagles, as well as humans, who trap them for food and fur. Muskrats vocalize a range of squeaks, chirps and whiney sounds, which often serve as warning of nearby intruders.

Then there's the name: muskrat. Muskrats communicate by gland secretion. No surprise, but they have a musky odor, appropriately called, well, musk. "Rather than being malodorous like skunk spray, it has a sweet smell," Gillespie says. "Its main purpose is for scent marking to convey the animal's presence in the area."

Farmers aren't fans of the muskrat. They eat farm grain and sometimes plug the drainage tiles in their fields. Since muskrats also have a habit of building their homes near dikes or dams, the lodges can weaken the structures and eventually destroy them.

So, when a bald eagle snatches up a muskrat for dinner, or a fur trader traps one, that actually helps keep the population in balance and more dikes and dams intact.

It may seem cruel, but there's no stopping the circle of life.