RODENTIA 293 



44,000 bags of grain out of 46,000 were cut by rats, the damage 

 amounting to $2,200. The damage caused by these rats is estimated 

 at $3,000,000 in Denmark, $40,000,000 in France, $50,000,000 in 

 Germany, $73,000,000 in Great Britain and Ireland; $193,615 damage 

 to business men in Washington, B.C., and $700,000 to business men 

 of Baltimore, in i year; probably $20,000,000 damage annually in 

 cities of more than 100,000 inhabitants in the United States. They 

 "kill more chickens than any other animal." 7 



Many publications contain directions for the destruction of rats, and 

 suggestions for the prevention of damage by them. 8 Among the meth- 

 ods for destroying them are trapping, poisoning, fumigating and the 

 use of ferrets, cats and dogs, though very few cats will attack rats and 

 many dogs will not. Deterrents, such as odors (naphthaline in large 

 quantities, creosote, carbolic acid, lysol, paracide, etc.), may be suc- 

 cessfully used in some cases to drive them from their hiding places, 

 where no foodstuffs are exposed to the fumes. All weed patches, rub- 

 bish piles and other hiding and breeding places should be eliminated. 

 All buildings should be rat-proofed by the free use of cement in 

 foundations and for basement floors, and sometimes metal to prevent 

 gnawing about doors. All unnecessary holes or openings in foundations 

 should be plugged and necessary openings such as drain pipes should 

 be screened. All food and garbage receptacles should be made rat- 

 proof and kept closed. Corn cribs may be protected by setting them 

 three feet above the ground, on posts topped by inverted tin pans. De- 

 priving the rats of food makes them hungry and more easily trapped 

 or poisoned. Depriving them of breeding places and hiding places and 

 driving them out into the open is one of the most effective methods of 

 preventing their increase. Community action is often necessary in cam- 

 paigns against rats, as against other pests, in order to get rid of sources 

 of infestation and to prevent continual inflow of new stock from ex- 

 traneous breeding grounds. In cities, professional rat hunters are often 

 employed very advantageously, as trapping and poisoning rats is not 

 an easy matter. They have acquired considerable resistance to strych- 

 nine and perhaps to other poisons. City building regulations should re- 



7 Fisher, Yearbook U. S. Dept. Agric. for 1908, p. 193. 



8 In addition to publications cited in preceding footnotes, see Claremont, A prac- 

 tical handbook on rat destruction, London, 1926. Silver, Rat control, Farmers' Bull, 

 No. 1533, 1927. Lantz, The brown rat in the United States, U. S. Biol Surv. Bull. 

 No. 33, 1909; House rats and mice, Farmers' Bull., No. 896, 1917. Dice, Lethal dose 

 of strychnine for the Norway rat, Journ. Mammalogy, rv, 188-189, 1923. Hovell, 

 Rats and how to destroy them, London, 1924. Reese, Outlines of economic zoology, 

 pp. 234-244, 1919. Munch, Silver and Horn, Red squill powders, U. S. Dept. Agric. 

 Technical Bull, No. 134, 1929. 



