OUR ANCIENT RELATIVES 



OUR LONG-SNOUTED ANCESTORS CROWD OUT THE 

 DINOSAURS 



For many millions of years during the Age of 

 Reptiles the ancestral mammals enjoyed all the 

 advantages of a higher level of vital activity, a 

 higher body temperature, a better locomotor 

 system, larger brains and more economical repro- 

 ductive methods, which had made them far supe- 

 rior in grade to the group from which they sprang. 

 Nevertheless, in all parts of the world where fossils 

 have been found these advantages did not enable 

 the mammals to supplant immediately their swarm- 

 ing relatives the reptiles. On the contrary, the 

 reptilian class, which very early broke up into 

 many orders, including the turtles, lizards, snakes, 

 crocodilians, dinosaurs, birds, flying reptiles and 

 many others, for millions of years dominated the 

 earth, while both the mammals and the birds 

 remained small and inconspicuous. For all the 

 millions of years during which the dinosaurs ruled 

 the land, the fossil record of life as it is preserved 

 in Europe and North America so far reveals 

 extremely few mammalian remains, and these only 

 from very thin layers in widely separated parts 



of the world. 



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