CHAPTER XVII 

 THE RAT PROBLEM 



The rat is the worst mammalian pest known to man. Its depredations 

 throughout the world result in losses amounting to hundreds of millions of 

 dollars annually. But these losses, great as they are, are of less importance 

 than the fact that rats carry from house to house and from seaport to sea- 

 port the germs of the dreaded plague. DAVID LANTZ, "The Brown Rat 

 in the United States," p. 9. Bulletin No. 33, Biological Survey, United States 

 Department of Agriculture 



The smell of mice shall be in their nostrils and they shall die. Old sayiwj 



To pay $1,000,000 for the last pair of rats on the North 

 American continent, after the Panama Canal is cut through, 

 and every harbor is properly sea-walled, might be money well 

 expended. The warfare which has been going on for thou- 

 sands of years might then be terminated in at least one conti- 

 nent and may not all good Americans unite in the hope 

 that ours may be the first continent of which this is true ? 



The failure of all attempts to deal with this vile enemy 

 may be traceable to lack of a vivid realization of what the 

 " last pair " may do in the way of increase. The brown rat 

 may breed five times in a season and have from 6 to 23 young 

 at a litter. Allowing 8 young, the increase from a single pair 

 in a season may amount to 880 ; and if we figure 10 in a litter, 

 this number is increased to 1250. In three years with only 6 

 young in a litter Lantz has computed the possible increase at 

 20,155,392. From these data it is clear that any scientific 

 method of dealing with this problem in any home or locality 

 must catch the last pair, and also, under existing conditions, 

 insure catching the first pair as soon as it comes, 



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