228 Field Museum of Natural History — Zoology, Vol. XT. 



Wisconsin. It is a semi-aquatic animal, spending the greater part of 

 its time in the water. Although largely noctiirnal in its habits, it is 

 often to be seen in the daytime either swimming about or sunning 

 itself on a log or along the shore. Like the Beaver it constructs a house 

 for itself for winter use, although it not uncommonly uses a hole which 

 it digs in a bank, often doing considerable damage to dams and canal 

 banks in localities where they are numerous. Bray ton says, "Along 

 the line of the Illinois and Michigan Canal, the 'canal walkers' are com- 

 pelled to keep a sharp eye to the Muskrats, lest they burrow through 

 the bank, and trappers, with their boats, are passed through the locks 

 and given the right of way along the tow-path." {I. c, p. 153.) 



Of the many muskrat houses which I have examined a description 

 of one will suffice. It was built in a marsh on the edge of a shallow 

 pond; and it was constructed of reeds, weed stalks and sticks mixed 

 with mud and was somewhat oblong in shape, although from a dis- 

 tance it appeared to be nearly round. The top of the rounded dome 

 was three feet high measured from the surface of the swamp and slight- 

 ly over four feet where built up from the side under water. The great- 



A Muskrat House. 



