CHORDATA — VERTEBRATA — REPTILES 



361 



known, the largest land animals that ever lived on this earth. 

 Brontosaurus excelsus (Fig. 154) from the Upper Jurassic of the 

 Rocky Mountain region was about sixty feet long; while 

 Atlantosauriis immanis from the same region was probably 

 eighty feet long by twenty or twenty-five feet high, and Giganto- 

 saurus, from East Africa, was still more immense. 



The problem of food supply for such huge animals must at 

 times have been very real. A full-grown Indian elephant weigh- 

 ing 8000 pounds eats 800 pounds of green fodder and 18 pounds 

 of grain per day. A Brontosaurus with a probable weight of 

 twenty tons would consume at least 4000 pounds of leaves 

 and twigs. If these animals, like the living reptiles, were cold- 

 blooded, they would eat somewhat less, but they may possibly 

 have been warm-blooded. The difference between the daily 

 rations of the w^arm-blooded lion and the cold-blooded crocodile 

 of equal weights is very slight. A twelve-foot crocodile of 415 



Fig. 155. — A restoration of the reptile, Stegosanrus ungulatus (Fig. 156), by C. R. 

 Knight. (From Lucas, through the courtesy of McClure, Phillips & Co.) 



