EIGHTH ANNUAL YEAR BOOK—PART X. 711 



METHODS OP DESTROYING RATS. 



U. 8. Department of Agriculture, Farmers' Bulletin No. 297 — By David 



E. Lantz. 



The brown or Norway rat (Mus norvegicus) is the worst mammal 

 pest in the United States, the losses from its depredations amounting to 

 many millions of dollars yearly — to more, indeed, than the losses from all 

 other injurious mammals combined.* In addition to its destructive 

 habits, this rat is now known to be an active agent in disseminating 

 infectious diseases, a fact which renders measures for its destruction 

 doubly important. 



Introduced into America about the year 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 or four times a year and produces from 6 to 12, and even 

 more, young at a litter. Young females breed when only 4 or 5 months 

 old. The species is practically omniverous, feeding upon all kinds of 

 animal and vegetable matter. It makes its home in the open fields, 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 fur, laces, silks, carpets, leather goods, and groceries. 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 the farmers' pigs, eggs, 

 and young poultry; eats the eggs and j^oung of song and game birds; and 

 damages foundations, floors, doors, and furnishings of dwellings. 



METHODS OF DESTEOYING RATS. 



A compilation of all the methods of destroying rats practiced in his- 

 toric times would fill a volume. Unfortunately, the greater number of 

 them are worthless or impracticable. Few have more than temporary 

 effect upon their numbers, and even the best of them fail unless per- 

 sistently applied. Conditions vary so much that no one method of dealing 



a Several gpecies of rats are known as ' ' house rats , ' ' including the black rat {Mus 

 rattus) , the roof rat (Mus alexandrinus) , and the brown rat (Af«s norvegicus) . Of 

 these, the last is the commonest and most widespread in this country. Not one of 

 these is a native, but all were imported from the Old World. As their habits in gen- 

 eral are similar, the instructions given in the bulletin apply alike to all. 



