THE ALLIES OF THE SQUIRREL 423 



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 greatly reduced. In some localities where 

 it is given protection, it is again becoming well established. 



Flesh-Eating Mammals. The carnivorous mammals, Car- 

 mVora (Lat. caro (cam-), "flesh"; vorare, "devour"), are 

 the flesh-eaters par excellence. The incisor teeth are small 

 and sharp ; the canines are generally long, strong, and coni- 

 cal, fitted for tearing; and the premolars and molars are 

 raised into more or less sharp ridges... The toes are sheathed 

 in claws, often fitted for grasping, and in one family, the 

 cats, are capable of being retracted and thus kept sharp by 

 being saved from constant friction. The group has divided 

 along two main lines of development, one adapted to terres- 

 trial, the other to aquatic, life. To the first belong the family 

 of cats (Fe'lidae), including the lion, tiger, leopard, lynx, jag- 

 uar, and puma ; the hyenas (Hyam'idae) ; the dogs, wolves, 



