RATS. 83 



one of these species is a native, but all were imported from 

 the Old World. As their habits in general are similar, the 

 instructions given in the bulletin apply alike to all. 



In addition to its destructive habits, the rat is known to 

 be an active agent in disseminating infectious diseases, a fact 

 which renders measures for its destruction doubly important 



Introduced into America about 1775, the brown rat has 

 supplanted and nearly exterminated its less robust relative, 

 the black rat, and despite the incessant warfare of man has 

 extended its range and steadily increased in numbers. Its 

 dominance is due to its great fecundity and its ability to 

 adapt itself to all sorts of conditions. It breeds three, four 

 or even more, times a year, and produces from 6 to 17 young 

 in a litter. Females breed when only 4 or 5 months old. The 

 species is practically omnivorous, feeding upon all kinds of 

 animal and vegetable matter. It makes its home in the open 

 field, the hedge row, and the river bank, as well as in stone 

 walls, piers, and all kinds of buildings. It destroys grains 

 when newly planted, while growing, and in the shock, stack, 

 mow, crib, granary, mill, elevator, or ship's hold, and also in 

 the bin and feed trough. It invades store and warehouse, and 

 destroys furs, laces, silks, carpets, leather goods and grocer- 

 ies. It attacks fruits, vegetables and meats in the markets 

 and destroys by pollution ten times as much as it actually 

 eats. It carries disease germs from house to house and 

 bubonic plague from city to city. It causes disastrous con- 

 flagrations ; floods houses by gnawing lead water pipes ; ruins 

 artificial ponds and embankments by burrowing; destroys 

 eggs and young poultry; eats the eggs and young of song 

 birds and game birds ; and damages foundations, floors, doors, 

 and furnishings of dwellings. 



Means of Repressing Rats. — Rats have developed so 

 much intelligence and such extraordinary caution that attempts 

 to exterminate them have rarely succeeded. The failures 



