6 



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



presence, with the erection of better buildings, with reduced use of 

 horses, and with improved rat-control methods, but progress in elimi- 

 nation has been slower than in cities or in small towns. The 

 total rat population of farms in the United States, which is fully 

 double the human farm population, may be estimated at 60.000,000. 



Adding to the 60,- 

 000,000 rats on farms, 

 the 34,000,000 rats in 

 nonfarm country 

 residences and in 

 towns of less than 

 10,000 population (1 

 rat per person) and 

 the 29,000,000 rats in 

 cities of 10,000 and 

 over (1 rat to each 2 

 persons) , the esti- 

 mated grand total 

 rat population for 

 the United States 

 amounts to 123,000,- 

 000, which is close 

 to the popular state- 

 ment that the rat 

 population approxi- 

 mates t h e human 

 population. 



ECONOMIC STATUS 



DESTRUCTION OF FOOD 

 AND OTHER PROPERTY 



In estimating the 

 losses chargeable to 

 rats, one must take 

 into consideration 

 not only the food 

 they consume and 

 waste, but also the 

 other property they 

 destroy and the cost 

 of controlling them. 

 About 50 pounds of grain or its equivalent are required to maintain 

 one rat for 1 year, representing a minimum annual cost of 50 cents 

 per rat for food actually consumed. On the farm, although much 

 waste grain that has no value is eaten by rats, yet the great bulk is 

 taken from corncribs and granaries, from shocks and sheaves (fig. 2), 

 and from mangers, pig troughs, and poultry yards. To offset the 

 waste grain eaten, rats usually eat just the germ of the corn kernel, 

 polluting the residue so that it is unfit either for seed or for feed. The 

 50 pounds thus actually consumed represent probably an additional 

 100 pounds of corn wasted. Also, some of the grain taken is planted 

 seed (fig. 3), so that the cost of the labor in planting and replanting 

 must be added to the grain cost. 



Figure 



-Rats are good climbers, and corn on the stalk is 

 an acceptable food supply. 



