CHAPTER XXXI 

 ANIMALS 



Distribution. Animals are found wherever the con- 

 ditions are suitable for their existence. The chief 

 external conditions which influence animal life are 

 food, oxygen, moisture, and suitable temperature. 

 There are only a few" places where these conditions 

 are not favorable to the life of some kind of animals. 

 In an ice covered region, like the interior of Green- 

 land, and in exceedingly dry areas, like the Sahara 

 and other deserts, there is almost no life of any kind. 

 With a few exceptions like these, animals exist every- 

 where in great numbers and in great variety. The 

 animal life of any region is known as its fauna. 



From personal knowledge most of us are already 

 familiar with the fact that animals differ very greatly 

 irrespective of their living places on the surface of 

 the earth. We know that the animals in our immediate 

 locality are unlike. The animals which are found in 

 the ponds and streams differ from those of the prairie ; 

 those of the field differ from those of the forest. The 

 greatest differences exist between the animals which 

 live in water and those which live on land. These 



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