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EVOLUTION OF ANIMALS 



Part V 



season, scatter off by themselves, and spend the summer in meadows and moist 

 woods. Their haunts vary with the species, but all are moisture seekers. 



Food. Adult frogs eat any animal they can get, of any size that they can 

 swallow whole, mostly invertebrates — insects, spiders, earthworms, snails, fish 

 fry, and their own tadpoles. The latter are strict herbivores that rasp and comb 

 soft water plants (Fig. 34.7). 





Fot body 



Fat body 



Fig. 34.7. Upper, mouths of tadpoles. Left, green frog, Rana clumitans: right, 

 spade foot toad, Scaphiopus holbrooki. Tadpoles of frogs and toads live on soft 

 plant food collecting it with the chitinous scrapers and combs that surround their 

 mouths. Different species have such different patterns of scrapers that they are 

 used as recognition marks. Lower, the relatively short intestine of a carnivorous 

 adult newt {left) and the long watchspring coil of the intestine of the herbivorous 

 tadpole of a bullfrog (right). The adult newt, Triturus, length 4 inches, lives on 

 aquatic worms, crustaceans and insects. The tadpole, length 2 to 4 inches, feeds 

 exclusively on algae and other soft plants of which it requires a large amount. 

 (Upper, courtesy, Wright: Life Histories of the Frogs of the Okefenokee Swamp, 

 Georgia. New York, The Macmillan Co., 1931.) 



