ANIMAL CYCLES 



179 



tions upon the fluctuations of numbers. Such defects in the method 

 appear inescapable, and hence the data derived from the fur trade 

 will probably for some time remain the best quantitative basis for 

 studying cycles among animals. 



An examination of the rabbit curve (Fig. 37), shows that the 

 greatest change in a year was a drop from about 285,000 to about 

 20,000 skins during 1845-46, while over against this are two rises of a 

 year each. The following table for the rabbit and lynx permits a 



TABLE 3 

 Phases of Rabbit and Lynx Cycles 



