MAMMALIA 



351 



concealment, as in the rabbit, though the rabbit will fight vi- 

 ciously by biting and by striking with its hind feet if cornered, or 

 if the nest or " form " containing the young is attacked. 



Some hibernate in winter, others migrate in flocks. They live 

 almost everywhere, but are chiefly terrestrial; some are aquatic, 

 some subterranean, and still others arboreal. They are very 



Fig. 284. American flying squirrel (Sdurop'terus volucella). (From Pack- 

 ard's ".Zoology," Henry Holt & Co., Publishers.) 



prolific, the young being numerous, and, in some families, four to 

 six litters a year. Since they are hardy, often nocturnal, and not 

 very particular as to the character of their food or lodging, they 

 have become worldwide in distribution. 



Squirrels (Sciu'ridce) are worldwide, excepting Australia and Madagascar. 

 The eyes and eais are large, the tail long and bushy, the thumbs on the fore 

 feet inconspicuous, There are four toes on the hind feet and the tibia and 



