"Our common Muskrat is a large rodent(up to 2 pounds) found nearly everywhere across the USA and Canada(none in Florida, parts of the southwest, Southern California and northern Alaska) where there are ponds, rivers, streams, marshes, swamps and canals"............"Armed with a thick coat of fur under its guard fur that is waterproof, they optimize their chances of surviving the most severe Winter weather inside dome-shaped mounds of marsh plants or create a riverbank burrow for shelter"........... "On the Muskrat menu are.cattails, sedges, rushes, water lilies, pond weeds, clams, mussels, snails, crayfish, small fish and frogs"........."They can dive underwater for up to 15 minutes to gather plants because their heart rate decreases and they draw oxygen from stores in muscle tissue"............It's a good thing that the female Muskrat can have up to five litters of up to 9 youngsters annually as they are a desireable dinner item for Wolves, Mountain Lions, Coyotes, Lynx. Bobcats, Foxes, Fishers, Mink, Otters, Black Bears, Snakes, Snapping Turtles, Hawks, Owls, Pike and Largemouth Bass

https://northernwoodlands.org/outside_story/article/in_homes_on_ice_muskrats_endure_the_season

In Homes on Ice, Muskrats Endure the Season

by Michael J. Caduto

Outside Story

March 16, 2009

7 Comments

12

Illustration by Adelaide Tyrol

In early March, when many cold-weary souls head south for a late winter respite, others spend their days in toasty ice-fishing shacks on still-frozen ponds and on the bays of quiet rivers.

They have company: In the midst of some of these avid anglers are muskrats, who have their own winter retreats — dome-shaped mounds of marsh plants that cover holes in the ice.  Inside these shelters the dark-brown rodents feed and rest during weather that would discourage the most hardened winter-sport enthusiasts.

Humans use gas-powered augers to drill holes in the ice; muskrats use their teeth. They gnaw four- to five-inch diameter holes and push marsh plants up through the ice to form their mound shacks.  Then they chew out the interior to create a place to eat, rest and catch a breath of air after swimming under the ice.


Muskrat territory(green shaded)

But just as human anglers have regular homes, muskrats have their own year-around homes. In river ecosystems they often live in burrowed bank dens, but in marshes their more-permanent lodges are constructed of plants, such as cattails, and mud. These houses rest on a firm base—the marsh bottom. Muskrats build these lodges by piling up the plants, then chewing out an opening and carefully layering much of the removed material to the top of the rising mound.

 Inside each house, which is about one and one-half to three-feet high, a family of three to five muskrats snuggles to stay warm.  If a lodge needs repairs, holes are patched with anything from water lily roots to frozen catfish pulled from the mud.

 Muskrats spend lots of time in their winter homes and their shacks — eating food from their autumn caches plus other marsh plants foraged under the ice.  They can dive for up to 15 minutes to gather plants because their heart rate decreases under water, and oxygen is drawn from stores in muscle tissue.  Thick, waterproof fur keeps them dry and warm.  Instead of being webbed like a beaver’s, the toes on their hind feet are fringed with stiff hairs, so they work like paddles. The muskrat’s long tail undulates to provide propulsion when the animal swims. The tail can be angled to act as a rudder.


Muskrat stream-side burrow hole

Muskrats are in many ways well adapted to survive the winter.  Diving muskrats can gather food without swallowing water because their lips seal shut behind the incisors.  Nimble front paws manipulate the roots of cattails, water lilies, arrowheads, pondweeds and other marsh plants.

Muskrats are large for a rodent.  Adults, weighing about two pounds and measuring roughly 20 inches from nose tip to the end of the 10-inch tail, make a tempting meal for various predators, such as minks, fox, weasels and marsh hawks.  Underwater predators include large northern pike, pickerel and snapping turtles.  To survive, muskrats are mostly active at night and during the hours of dawn and dusk. They aren’t strict vegetarians; they will eat fish, clams, crayfish, frogs and snails.

Muskrat Domed Burrow

Winter can be treacherous. Paul Errington, the renowned hunter, trapper and wildlife biologist, recorded dramatic moments in muskrat lives in his landmark book, “Of Men and Marshes.” He mentions a morning encounter: “The whole top of the lodge shell is open, empty of muskrats, and powdered by the trace of snow.  A mink-killed muskrat lies smeared with blood on the ice, and a drag trail represents another victim.” 

So it can be bloody out there on the ice. Half of the muskrat population can die by mid-winter.  Sometimes during cold snaps the openings to their push-up lodges freeze shut, closing off opportunities for oxygen and nourishment.  As winter progresses, competition for food intensifies, forcing muskrats to venture out into the open, where they can succumb to cold or predation.

When spring finally arrives, the muskrat winter camps collapse during “ice-out.”  But by then, the muskrats are traveling about on land, depositing a powerful scent along their routes to denote their territory. They also mate.

In early spring the adults kick the previous autumn’s youngsters out of the house.  Then, in April or May, about a month after mating, a new litter is born. Around mid-summer, these little muskrats are driven away to make room for a second litter.  And by the time the ice-fishing shacks appear again, adult muskrats, along with the late-summer crop of young, will be hunkered down in their own winter homes and shanties.

Michael J. Caduto is an author, ecologist and storyteller who lives in Chester, Vt.

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http://www.nhptv.org/natureworks/muskrat.htm

Common Muskrat -  Ondatra zibethicus
Characteristics Range Habitat Diet Life Cycle Behavior	Classification  Phylum: Chordata  Class: Mammalia  Order: Rodentia  Family: Muridae  Genus: Ondatra
ICUN Redlist - World Status:  Least Concern

Characteristics The muskrat is a large rodent that is is about a  foot to two feet long. It has a stocky body, a  rounded head and a long, scaly black tail that  is 7 to 12 inches long. Its tail is laterally  flattened, that means it is flattened vertically! Its tail works like a rudder  and helps the muskrat maneuver in the water! It has thick, soft, glossy,  reddish-brown to dark brown fur  on its uppersides and paler fur on  its undersides. Coyote with a Muskrat meal  It has a thick coat of fur under its guard  fur that is waterproof. It may also have a white patch of fur under its chin and a  darker patch of fur on its nose. The  muskrat has small eyes and tiny ears.  It has short legs and small front feet. Its rear feet are larger and slightly  webbed. It gets its name from the  two musk glands on its rear under its tail.   Range The muskrat is found from northern  North America south to the Mexican border. It is not found in parts of  California, Florida, and Texas. Mink with a Muskrat meal   Habitat The muskrat is found in swamps, marshes,  rivers, ponds, lakes, drainage ditches and canals. It prefers an environment with four  to six feet of still or slow-moving water and  plants like cattails, pondweeds, bulrushes  and sedges. It needs open travel channels in the water so it can move around easily. In marsh environments, the muskrat builds  a dome-shaped lodge of plants. The lodge  can be five feet across and four feet high and has an inner chamber with more than  one underwater entry hole. In some cases,  the muskrat may build separate lodges for feeding and nesting! In other habitats like  rivers, creeks, drainage ditches and canals,  the muskrat creates a bank burrow for shelter. The burrow consists of a tunnel  and a nesting chamber. There is usually an underwater entrance to the burrow.  Great Horned Owl with a Muskrat meal  Diet The muskrat can close its mouth around  its protruding teeth and chew underwater!  The muskrat eats aquatic vegetation like  cattails, sedges, rushes, water lilies and  pond weeds. In some areas it also eats clams, mussels, snails, crayfish, small  fish and frogs. The muskrat doesn't eat  its food where it finds it, it usually drags its food out to a feeding platform in the  water or a feeding station near one of  its travel paths. These feeding platforms are made of mud and vegetation. It can  then eat its food without worrying about predators! The muskrat is crepuscular, that means it is most active at dawn, dusk and at night.  Red Fox with Muskrat meal   Life Cycle In the southern part of its range the muskrat  may breed year-round. In the northern parts  of its range mating season runs from March  through August. The female muskrat may have up to five litters a year. Male muskrats compete for females. The female gives birth  to two to nine young. The young are covered with fur at birth and their eyes are closed. They can swim when they are about ten days  old and begin to eat vegetation when they  are about 20 days old. They are fully weaned when they are about a month old. They leave their mother after weaning and establish their  own territory. They mate when they are about  a year old. The average lifespan of a muskrat  in the wild is three or four years. Red-Tailed hawk with Muskrat meal   Behavior The muskrat is a very good swimmer and  can stay underwater for as long as 15 minutes.  It uses its tail and webbed feet to propel itself through the water and can swim both forwards  and backwards!