10 



CIRCULAR 4 2 3, U. S. DEPARTMENT OF' AGRICULTURE 



Numerous articles of doubtful food value, also, such as soap, paint, 

 bone, and leather (figs. 11, 12, 13, and 14), are destroyed by their 

 gnawing. 



In dry goods and furniture stores rats can figuratively destroy their 

 weight in gold by gnawing for nesting material through bolts of 



silk and into expen- 

 sive upholstery. 

 Even in office build- 

 ings and libraries 

 they have caused se- 

 rious losses by using 

 valuable paper for 

 their nests and by 

 eating the glue from 

 book bindings. 



After making a 

 careful rat-loss sur- 

 vey in Washington, 

 D. C, and Baltimore, 

 Md., in 1907, D. E. 

 Lantz, of the Bureau 

 of Biological Survey, 

 stated that he could 

 conservatively place 

 the yearly rat loss 

 for Washington at 

 $400,000 and for Bal- 

 timore at $700,000, 

 which was not much 

 more than $1 a year 

 for each of the hu- 

 man population. 

 With 10 years' added 

 experience and be- 

 cause of advancing 

 food and property 

 prices, Lantz saw fit 

 to raise this figure in 

 1917 to $2 per year 

 per rat (estimating 

 equal numbers of 

 rats and people ) , 

 and since then this 

 figure has been ac- 

 cepted generally by 

 students of the sub- 

 ject. As a result of 

 rat-loss surveys made 

 in Winston-Salem, 

 N. C, in 1928, and in Dallas, Tex., in 1931, a Biological Survey rep- 

 resentative fixed the loss in the former city at $100,000, or nearly 

 $1.50 for each human inhabitant, and in the latter city at $356,000, 

 or $1.35 for each person. On the basis that there is only one rat for 

 each two persons living in these cities, the loss caused per rat would 



FlGUBE 7. 



-Rat damage to wires explains some interruptions 

 to telephone service. 



