THE ALLIES OF THE SQUIRREL: MAMMALIA 419 



in the upper jaw. Well-known American species are the 

 cottontail, or gray rabbit, of the East (Le'pus florida'nus), the 

 varying hare (Lepus america'nus) of the North, and the north- 

 ern jack-rabbit (Lepus campes'tris) of the West. The cottontail 

 is so named from the white tail, which is plainly shown in 

 flight and probably serves as a signaling or recognition mark. 

 The varying hare is a larger and more northern species which 

 takes on a white coat of fur in winter. The northern jack- 

 rabbit also changes to white in the northern part of its range ; 

 farther south the change is only partial or entirely wanting. 

 The domestic rabbit is descended from the common rabbit of 

 the Mediterranean basin (Lepus cunic'ulus). 



The porcupine (Erethi'zon dorsa'tus) is a sluggish, stupid 

 animal, which, having spines for protection, relies on them 

 to such an extent that it hunts its food in the daytime, 

 a habit which most rodents have had to give up (if they 

 ever possessed it) on account of their lack of protection and 

 means of defense against numerous enemies. The squirrels 

 have solved the problem in another way by the development 

 of extreme watchfulness. There is no truth in the oft- 

 repeated statement that the porcupine can shoot its quills, 

 the fact being that, as they are loosely attached, they are 

 likely to come out on slight pressure. 



So much has been written on the beaver and its works 

 that its habit of felling trees for its dam or for food, its win- 

 ter storage of branches or twigs beneath the ice, and the 

 habits developed in connection with its communal life are 

 pretty well known to everybody. In the communal life of 

 the beaver, as among the bees and wasps, instinctive actions 

 are performed with a high degree of perfection. The beaver 

 also has capabilities of meeting new conditions, and it has 

 been credited with a considerable degree of intelligence. 

 It has been hunted so persistently for its fur and scent- 

 bags that it is now almost extinct. The few remaining 



