THE BROWN RAT IN THE UNITED STATES. 



INTRODUCTION. 



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

 tions 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 seaport the germs of the dreaded plague. 



Once occupying only a comparatively small part of the Old World, 

 through the spread of commerce the brown rat has been furnished free 

 transportation to the uttermost parts of the earth, while its fecundity, 

 cunning, and adaptability to almost every kind of environment have 

 enabled it to nourish and multiply wherever it has secured a foot- 

 hold. 



Man s antipathy to the rat is not new. For centuries the animal 

 has been banned, and human ingenuity has been taxed to the utmost 

 to suppress it. Innumerable devices in the way of traps, poisons, 

 gases, and, more recently, cultures supposed to spread fatal diseases 

 have been resorte n I , Nevertheless, the pest continues to prosper, 

 and its numbers and destructiveness keep pace with the advance of 

 civilization. ^Everywhere the history of the contest is the same. 

 Though thousands are killed, the relief is only temporary, and other 

 thousands soon replace the slain. Therefore, if conducted along the 

 old lines, the war promises to be never-ending. 



The futility of past efforts and the lack of permanent results in- 

 dicate that the real cure for the rat evil in cities, especially seaports, 

 lies in preventive rather than curative methods. The extraor- 

 dinary success that has attended the rat's struggle for existence is to 

 be explained largely by the abundance of food and shelter furnished 

 by man. Preventive measures should be directed to withholding 

 these advantages. The curtailing of food is less important in its effect 

 on the present rat population than in its certain result in lessening 

 reproduction. Abundance of food means many } r oung in a litter 

 and many litters in a year; a restricted supply means fewer young 

 and fewer litters. The most important steps, therefore, toward the 

 suppression of the rat are : 



(1) TJie enactment and strict enforcement of municipal ordinances 

 providing for the disposal of garbage and the protection of food supplies. — 

 Ever}^ effort should be made to instruct the public as to the necessity 

 81155— Bull. 33—09 2 9 



