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Throughout its range, wherever there is quiet water with abun- 
dant aquatic or riparian vegetation, the muskrat is sure to be found 
unless driven away by persistent persecution. In early days the 
sloughs that covered a large part of the prairie were the resort of 
thousands of these animals. Here they found plenty of food and 
comparative safety from their enemies. As these swampy areas 
have been drained, the range of the muskrats has become restricted 
to drainage ditches and the natural watercourses. Although this 
change in the environment has necessitated a change in habits, the 
muskrats, with a strange persistence, still remain, and wherever 
in the till plains or in the sags of the moraines there is still open 
water enough to wet their feet, traces of their presence may be 
found. They will not disappear until the drainage is entirely under 
ground. 
In this vicinity the burrows of the muskrat along the banks of 
streams and ditches open near the level of moderately low water, 
and extend back some yards into the bank. There are usually open- 
ings to the surface also, back some distance from the water. Some 
of these openings are the work of the muskrats, but many of them 
are due to the breaking-through of men or animals into the burrows. 
When the country was new the muskrat houses were a promi- 
nent feature in the landscape, and they may still be seen occasion- 
ally. Observers differ greatly in regard to the conditions under 
which muskrats may or may not build houses. Evidently their 
habits in this respect differ in different localities. In the lakes and 
marshes of Wisconsin, Minnesota, and Canada they build houses in 
two to four feet of water wherever conditions permit. In this 
vicinity the houses are found in much shallower water, and in the 
southern part of its range the muskrat does not build houses at all. 
This has apparently become a matter of individual variation in this 
county, for one finds only a small proportion of these animals using 
houses where, so far as one can see, conditions are equally favorable 
for all to build them if they wished. These houses serve a double 
purpose, furnishing both shelter and supplies of food—the interior 
part consisting of such food plants as are available in the locality. 
The houses are built solid at first, the interior excavation being made 
later. While the bottom and interior part are composed of closely 
packed food-plants, above and on the exterior dirt is mixed with 
them, and, occasionally, drift materials. Where the water is deep, 
