WHY DO ANIMALS BECOME EXTINCT? 



feres. He either kills and eats animals, or takes 

 their food from them, or occupies their ground, 

 or cuts down the forests in which they live, and 

 so on. But before man appeared on the scene 

 there were changes going on, and different 



Fig. 18.— The living Giant Tortoise of the Court House, 

 Mauritius, more than 150 years old. 



kinds of animals succeeded one another. We 

 know this by finding the remains of different 

 animals at different depths in the crust of the 

 earth, in the different strata which have suc- 

 ceeded one another. The cause of these 

 changes, the cause of the extinction of animals, 



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