To insure successful trapping 

 operations, plenty of traps should 

 be used. As with bait, consider- 

 ably more ti'aps should be put out 

 than would seem necessary. 



OTHER METHODS 



Many other methods and tech- 

 niques for killing rats have been 

 advocated, but the three general 

 methods previously discussed give 

 the most satisfactory results. For 

 the most part, other means of 

 destruction are rarely as efficient, 

 or must be relegated to the role 

 of superstition and folklore. 

 Shooting rats, while sometimes an 

 amusing sport, will not achieve 

 control of an entire population. 

 Small terrier dogs and, rarely, 

 cats will kill occasional rats that 

 they find, but cannot rid the prem- 

 ises of the pests. Ferrets, also, 

 have been used to kill rats, but 

 they are too unreliable and de- 

 stroy too few rats to be a prac- 

 ticable control factor. Such nat- 

 ural enemies as hawks, owls, and 

 snakes should be encouraged to 

 remain about the premises rather 

 than destroyed, but they cannot 

 be relied upon for comiolete con- 

 trol. Repellents of many kinds 

 have been suggested, but, as they 

 dissipate rapidly, their use is lim- 

 ited to small confined spaces, and 

 even there they must be replen- 

 ished constantly. Furthermore, 

 they bring about no decrease in 

 the population. Glue boards, 

 based on the same principle as fly- 

 paper, have been prepared, but 

 they are very messy, and besides, 

 rats soon learn to avoid them. 



Virus diseases, supposedly ca- 

 Dable of starting an epidemic 

 among rat populations, have at- 

 tracted some interest, chiefly be- 

 cause of the spectacular nature of 

 the method. Those tried, how- 

 ever, have rarely proved effective. 



Rats killed by eating the infected 

 food had to be eaten l^y another 

 rat in order for the disease to he 

 passed on. Furthermore, the bac- 

 teria used belong to the same 

 group as the food-poisoning ba- 

 cilli and have caused some deaths 

 among human beings. Some lo- 

 calities have prohil^ited the sale or 

 use of the so-called rat viruses. 

 For these reasons, they are not 

 recommended. 



There are many other methods 

 that are popularly supposed to be 

 eflfective in killing rats, but all 

 have proved ineffective. Ever 

 since the dissemination of the 

 legend of the Pied Piper, man has 

 been searching for some easy way 

 to get rid of rats. The sooner it 

 is realized that downright hard 

 work is the only solution, the 

 sooner adequate control will be 

 attained. 



REMOVAL OF RAT 

 HARBORAGES 



Unless the places in which rats 

 are living are destroyed and po- 

 tential habitations broken up, con- 

 trol methods are rarely success- 

 ful. Rats can always find enough 

 food available to sustain life. As 

 long as a place to hide and rear 

 young exists, they will continue to 

 survive. Studies have shown that 

 after a poisoning campaign the 

 rat population will regain its for- 

 mer numbers within about 9 

 months or less if no other control 

 measures are undertaken. 



The common brown rat lives 

 underground, beneath stored ma- 

 terials, behind double walls, and 

 in other similar enclosed spaces. 

 After a thorough poisoning pro- 

 gram, these harborages must be 

 eliminated as far as possible. All 

 burrows should be broken up. 

 Stored materials should be placed 

 on racks 12 to 18 inches off the 

 ground (fig. 11). If the woodpile 



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