538 LIFE AS RELATED TO PHYSICAL CONDITIONS 



to one another, it might be expected that the animals of 

 these continents would resemble one another, particularly 



in the more northern 

 parts. This is true. 

 Bears, wolves, foxes, 

 elk, deer, and sheep of 

 nearly related species 

 are found distributed 

 over the northern con- 

 tinents. 



The animals of the 

 southern continents 

 are much less nearly 

 related. The ostrich, 

 giraffe, zebra, and hip- 

 popotamus are among 

 the characteristic ani- 

 mals of Africa which are not found elsewhere. In South 

 America the tapir, great anteater, armadillo, and llama 

 are among the animals not represented elsewhere. Both 

 of these continents, 

 however, have ani- 

 mals ^closely related 

 to those of other 

 great divisions, show- 

 ing that their present 

 isolation has not con- 

 tinued far back in 

 geological time. 



The animals of 

 Australia differ 

 greatly from those 



OSTRICHES 

 The largest of all birds. 



OPOSSUM 



Many opossums have no pouch but carry 

 their young on their backs. 



