F I B E R zi B E r Ulcus. 179 



takes up its abode near dykes or dams, its perforations are liable to 

 do great mischief. 



In moving about on their feeding grounds Muskrats are in the 

 habit of travelling along the same paths till they become deeply worn 

 channels. Steel traps properly concealed in these runways are 

 almost certain to capture- the first animal that passes. 



In places where the water is from two to six feet deep the Musk- 

 rat, in the fall of the year, somedmes collects and heaps together a 

 large quantit)- of aquatic and marsh plants, the resulting mass taking 

 a shape not unlike that of a " haycock," though commonly far less 

 symmetrical. This accumulation of vegetation, with more or less 

 adhering mud,'^' is called a Muskrat " hut " or " house." It varies 

 greatly in size, those placed in water occasionally attaining extraordi- 

 nary dimensions. The summit of the structure is commonly hicrh 

 enough out of water to admit of an air-chamber within, which com- 

 municates with the outside world by means of a hole throucrh the 

 centre of the mass, the entrance or entrances being under water. 

 Many of the houses contain no mud or sticks, but consist wholly of 

 balls and knots of roots and swamp grasses. It seems clear that the 

 animals make no attempt to construct a dwelling of any particular 

 shape, but merely heap the materials together without plan or order, 

 the resulting mound naturally assuming, in a general way, the form 

 of a flattened cone. In some cases the summit is quite dome-shaped, 

 but I am convinced that this is purely the result of accident, for 

 their upper parts are usually very irregular. The materials of which 

 the hut is composed, it will be observed, are such as serve as food 

 for the animals during the long winters ; hence the Muskrat's house 

 is, in reality, a store-house, which he devours piecemeal as the winter 

 advances ! The one structure supplies both the food itself, and the 



■* I have never seen a ^Tuskrat house that was built of mud, or that even consisted largely of this 

 material ; but they must occur in certain localities, for no less trustworthy an authority than Sir 

 John Richardson wrote: "In the autumn, before the shallow lakes and swamps freeze over, the 

 Musquash l)uilds its house of mud, giving it a conical form, and a sufficient base to raise the 

 chamber above the level of the water." (Fauna Boreali Americana, Vol. I, 1829, p. X17.) 



