THE EVOLUTION OF THE ELEPHANT 



leaves and twigs. The shovel-teeth were no longer needed. 

 The long lower jaws were no more an advantage. So we 

 come to a series of elephants in which the lower jaw is 

 shortening. The necessity for reaching the ground, at least 

 for water, still remains, and for this purpose the long upper 

 lip is used, but being no longer supported it becomes pen- 

 dant, a proboscis. These new forms with a shortened lower 

 jaw are the mastodons. There are many intermediate stages, 

 such as Mastodon longivostris of the lower Pliocene of Ger- 

 many, in which the lower jaw is still of considerable length. 

 Mastodon atticus from Pikerni, in Greece, has a long chin, 

 and while young has incisors in the lower jaw. Throughout 

 the Pliocene there are several species of mastodons in Europe 

 and Asia. By Pleistocene time they had reached North 

 America, where they flourished throughout the Ice-Age and 

 for a short time afterward. Among even the American mas- 

 todons there is occasionally found one which has vestiges of 

 tusks in the lower jaw, like the one at Amherst College, 

 which has tusks nine inches long. 



The upper tusks, after they were no longer used for dig- 

 ging, did not disappear, as would be expected, but instead 

 turned upward and forward, increasing in size, so that those 

 of a well-grown adult are usually seven to eight feet long, 

 and a single tusk weighs over a hundred pounds. Projecting 

 so far in front of the animal they may be of some use in 

 pushing or lifting, perhaps in fighting; but these uses can 

 hardly compensate for the inconvenience of such projections, 

 or for the effort involved in carrying so much weight out in 

 front of the head. Like the antlers of the elk or moose, they 

 seem to be overdeveloped structures, and were probably 

 among the features that caused the extermination of these 

 great beasts. Though the mastodons flourished throughout 

 the Pleistocene epoch and for a short time thereafter, they all 



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