94 



The National Geographic Magazine 



Photo by Viola McColm 



NOT DEAD, BUT PLAYING POSSUM 



squirrels of Washington injures the 

 wheat crop in a single county of that 

 State to the extent of half a million dol- 

 lars annually. While the loss to this 

 country by rodents by no means equals 

 that caused by insects, the total reaches 

 far into the millions and is a serious drain 

 on the national resources. 



To devise methods of combating these 

 pests, of reducing their numbers, and, if 

 possible, of accomplishing their exter- 

 mination is one of the important problems 

 dealt with by the Biological Survey. By 

 the use of traps, of poisoned foods, and 

 of gases to kill the animals in their bur- 

 rows, much has been accomplished. 

 Failure to secure the utmost results 

 aimed at by these methods is due chiefly 

 to the difficulty of securing the coopera- 

 tion of all the farmers in an infested re- 

 gion. It is evident that if a number of 

 landholders withhold their aid, their 

 farms become nurseries from which to re- 

 populate adjoining districts. Moreover, 

 in most regions there are sterile and un- 

 productive areas which receive no atten- 



tion, and these again are harbors of ref- 

 uge for the pests which later emerge to 

 restock farming lands. Hence the con- 

 test appears to be a never-ending one, 

 and is a constant source of loss and an- 

 noyance to the farmer. 



The difficulties of warfare against ro- 

 dents are in inverse proportion to the set- 

 tlement of the country. Where farms are 

 large and there is much waste land, the 

 difficulties are very great; but when 

 farms are comparatively small and there 

 is little unoccupied land, cooperation be- 

 tween landholders is easier to secure and 

 results are more encouraging. In parts of 

 Kansas, for instance, where formerly 

 farming population was scarce and 

 prairie dogs numerous and destructive, 

 the animals have been practically ex- 

 terminated as the result of the continued 

 effort of numerous ranchers working to- 

 gether for a common end and aided by 

 the state. 



In attempting to devise more effective 

 means of abating rodent pests the atten- 

 tion of the Survey has been turned to a 



