THE BLACK-TAILED HARE 229 



At times rabbits become so plentiful that 

 they are seen almost everywhere in the open 

 country, and then after this there may come 

 years when they seem to have in large part dis- 

 appeared. Many old prospectors and ranchmen 

 will tell you that this is because food is scarce 

 and that the rabbits have gone to better feed- 

 ing-grounds. This is an error. While food de- 

 ficiency may have something to do with the 

 ability of great numbers of rabbits to subsist in 

 any region, yet their scarcity at certain periods 

 cannot be accounted for wholly on this basis. 

 These rodents are subject to several contagious 

 maladies which at times so reduce their num- 

 bers that it would seem there were scarcely 

 enough healthy ones left to replenish their kind. 

 But those that survive manage to repopulate 

 the fields in a remarkably short time, and the 

 ranchers are all too soon complaining about 

 "too many jack rabbits " again. 



The water blisters often found on hares are 

 due to the presence of the larval form of a 

 tapeworm. The late Dr. Katherine Brandegee 

 worked out the life-history of this parasite, and 

 I give her words concerning it: 



