the bank and go back into the cornfield about fifty feet and cut 

 the dry corn stalks and drag them to the slough, where he was 

 busy building- a winter home with them. 



Besides the houses, nuiskrats sometimes live in burrows in 

 banks. They are chiefly nocturnal and are active the year around. 



The muskrat's food consists of aquatic plants, sedges, pond 

 lilies, garden vegetables, beets, parsnips, cabbage, celery and the 

 like. They also feed on mussels. The writer has in mind a slough 

 near Fort Collins that, a few years ago, was well stocked with 

 mussels, but muskrats got in and now not a mussel is to be found. 



Muskrats are very abundant on Harvy Gulch Mesa, near Silt, 

 Garfield County, where, in some of the fields, they burrow out 

 from the irrigating ditches and eat the sugar beets. 



They also burrow under the ditch banks, causing them to cave 

 off and fill the ditches with earth to such an extent that the ditches 

 have to be cleaned out every spring before the water can be run 

 in them. They also cause serious breaks in reservoir banks. I 

 have known of only one case of albinism in muskrats. A cream 

 colored one was caught a few years ago near Fort Collins. Musk- 

 rats have been known to enter cellars where they are located near 

 streams, their entrance being made through drain pipes from 

 cellar to stream. The writer's attention was called to one case 

 of that kind where they had destroyed a number of stored potatoes. 



SUBFAMILY MURINAE 

 Genus Rati us (Rats) 



Three members of this genus are found in the United States, 

 only one of which is found in Colorado, the common House-rat. 

 These three species have all been introduced by man into this 

 country from the Old World. House-rats have ears short, naked 

 or nearly so, tail long and scaley and nearly naked. Upper parts 

 rusty grayish brown, underparts ashy white. Total length from 

 12 to 17 inches. 



House-Rat, RcUtus norvegicus. 



House-rats in the last few years have invaded most of the 

 eastern part of the State. We have records of captures from 

 Longmont, Boulder, Flagler, Barr, Loveland, Fort Collins, Greeley, 

 Eads, Julesburg, Ault, Pueblo, Holly, Lamar, Windsor, Sterling, 

 Colorado Springs and Denver. 



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