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MAMMALS OF AMERICA 



HOUSE RAT 

 Epimys norvegicus ( Erxlcbcn ) 



Other Names. — Norway Rat, Brown Rat, Gray Rat. 

 Barn Rat, Wharf Rat. 



General Description. — The common Rat to he seen 

 about cities. Head of normal size; nose pointed: 

 muzzle naked at extremity ; ears and eyes rather large ; 

 body moderately large; tail long, about half of total 

 length, nearly naked, with rings of overlapping scales ; 

 legs of normal proportions ; hind foot with six tubercles 

 on the naked sole; no cheek pouches: fur rather coarse 

 than soft. 



Dental Formula. — Incisors, ;^ ; Canines, ~l^^ : Pre- 

 molars, —— ; Molars, 



o — o ' 



Pelage. — .'Adults ; Sexes identical, seasonal varia- 

 tion slight. Normal coloration grayish-brown above; 

 dirty grayish-white below ; upper surface with more or 

 less black hairs especially along the dorsal area ; feet 

 soiled grayish-white ; tail dusky above and rather 

 lighter below, though not distinctly bicolor. Hair on 

 tail short and so sparse that the annuli may be plainly 

 seen. Young : Grayer than adults. 



3" 3_,, 



Measurements. — Total length, 15.7 inches ; tail 

 vertebrae, 7.5 inches; hind foot, 1.6 inches. 



Range. — Practically cosmopolitan. In North Amer- 

 ica found in nearly all cities and the larger settlements. 



Food. — Omnivorous to a large extent. 



Related Species 



Norway Rat. — Epimys norvegicus (Erxleben). 

 Typical animal as described above. North America 

 about the habitations of man. 



Black Rat. — Epimys rattiis rattus (Linnaeus). Size 

 smaller than Norway Rat ; tail longer, more than half 

 the total length ; color above plumbeous-black, below 

 slate-black. Found only in scattered localities, mainly 

 in the southern and southwestern United States. 



Roof Rat, or Alexandria Rat. — Epimys rattus alcx- 

 andrinus (GeofFroy). Smaller than Norway Rat. about 

 size of Black Rat; tail very long, more than half total 

 length : color reddish-brown above, yellowish-white to 

 whitish below. Found in scattered localities. 



Photograph by West Va. University Experiment Station 



HOUSE RATS IN TRAP 

 The Rat will fight viciously when cornered, and has been known to put the cat to flight 



