Forest Preserve District of Cook County, Illinois
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The Muskrat -- Little Brother of the Beaver
Nature Bulletin No. 537   September 27, 1958
Forest Preserve District of Cook County
Daniel Ryan, President
Roberts Mann, Conservation Editor
David H. Thompson, Senior Naturalist

In the Algonquian Indian languages he was called Musquash. The Hurons called him Ondatra and that hag now been adopted as his scientific name. But the best Indian name of all meant "little brother of the beaver". He gnaws like a beaver, swims like a beaver, builds houses like a beaver, and looks like a little beaver. He call him Muskrat because, also like the beaver, he has a pair of musk glands used to leave messages for others of his kind.

This is the most important fur bearer to professional trappers and the American fur industry. More than any other wild animal, the muskrat converts millions of acres of cattail marshes and weedy shores into a crop of fur and flesh. To the farm boy with a few traps it means money in the pocket and experience in the skills of outdoor life. Our womenfolk prize rich warm coats of Hudson seal, the trade name for muskrat fur. The dark red meat has a wild game flavor but, because the word "rat" is unpleasantly suggestive, muskrats appear on menus under such names as Marsh Rabbit and Maryland Terrapin.

Sometimes these animals become a pest, raiding corn fields and other farm crops near the water's edge, but they do the most damage to earthen dams, dikes, levees and canal barks which are occasionally destroyed through leaks started by their burrows. In our Cook County forest preserves, however, the muskrat plays a star role in establishing and maintaining natural landscapes and a natural balance among the wildlife of almost a hundred bodies of water which have been created or restored during the past thirty years. Neither they nor any other wild animal may be hunted or trapped in any of the preserves.

In cattail marshes and other shallow weedy waters, muskrats pile up great heaps of aquatic plants to build a house or lodge that has, inside, a warm living room reached by an underwater entrance. From this home they range out to feed on the succulent roots and stems of such plants, even under thick ice in winter. However, in streams, farm ditches, and in many ponds and lakes -- especially during summer -- muskrats live in burrows dug deep in the banks. Those burrows start beneath the surface and slant upward to an enlarged chamber above the water level.

The muskrat is a thickset short-legged animal with a foot-long body about the size of a small cat. The adults average two pounds in weight but, rarely, reach four. It has a 10-inch black scaly tail which is flattened vertically -- unlike the broad paddle-like tail of a beaver. This tail is used as a rudder, or to scull slowly, or to smack the water as a danger signal. The fur is dark brown on its back, with very thick waterproof underfur and long reddish-brown guard hairs that glisten.

The "rat" has small beady eyes and ears which are nearly hidden in the dense fur. The hind feet are large, webbed between the toes, and used like the flippers worn by skin divers. While swimming, the small forepaws are folded underneath the chin. Like all rodents, it has a pair of chisel-teeth or incisors above and below, separated from the grinding teeth or molars by a gap, and its lips can be closed behind the chisel- teeth to keep water out of the mouth while gnawing beneath the surface.

A muskrat is clumsy and glow on land, seldom venturing away from water in daytime, but it is a courageous scrapper when attacked or cornered. Next to trappers, its greatest enemy is the mink which raids muskrat houses and burrows to eat their young.

In trappers' language they are "mushrats" or just plain "rats".

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