Feb., 191 2. Mammals of Illinois and Wisconsin — Cory. 177 



Special characters — Under parts grayish brown, paler than the back 

 but with no abrupt line of demarcation; length, 6 to 7 inches. The 

 grayish brown under parts (not white or whitish), in connection 

 with its size and length of tail, will distinguish it from others of our 

 Mice. 

 Description — General color brown, the dark brown shading gradually 

 to lighter brown on the sides of the body and grayish brown on the 

 belly; tail very scantily haired; molars or grinding teeth having tu- 

 bercles on crowns forming three longitudinal rows. 

 Measurements — Total length, 6.75 in. (171. 4 mm.); tail vertebrae, 

 3.15 in. (80 mm.); hind foot, .75 in. (19 mm.). 

 The House Mouse is an introduced species which has become 

 distributed practically throughout North America in districts inhabited 

 by man and occasionally away from settled localities. On account 

 of its small size it does not do so much damage as its larger relative, the 

 Rat, but its presence is considered equally undesirable, and its ability 

 to get through very small holes often enables it to gain access to the 

 drawer of a desk, where it immediately begins operations by reducing 

 letters and papers contained therein to a mass of shreds to be used as a 

 soft bed for a litter of young Mice. When present in any numbers the 

 amount of food they consume is considerable, and their depredations 

 in pantries and storerooms is too well known to require comment. 



They are unfortunately very prolific, several litters being born in a 

 season. From 4 to 9 young are born in a litter, the usual number being 

 5 or 6. The young ones reach the age of maturity when less than three 

 months old. 



The ordinary vocal sounds produced by a House Mouse may be 

 described as a shrill squeak, but several writers have given it credit 

 for what they describe as a "song." Mr. Seton says,* ''Most persons 

 are surprised to hear of singing Mice. The first I met was in my New 

 York residence. Out of the black darkness of a cupboard at midnight 

 came a prolonged squeaking, thrilling and churring, suggestive of a 

 canary's song but of thinner and weaker quality. There could be no 

 question that it was a 'singing mouse.' Many cases are on record." 



All efforts to exterminate the House Mouse in the United States have 

 failed and, if anything, their numbers appear to be increasing. In 

 this connection it is interesting to note that three hundred years ago 

 the householder in England was annoyed by these little pests fully as 

 much as are those of the present day; at least in 1607 Edward Topsell 

 devoted several pages to describing various methods whereby they could 

 be trapped or killed. He says:t 



* Life Histories of Northern Animals, I, 1909, p. 482. 



t Historie of Foure Footed Beastes, London, 1607, pp. 509-510. 



