The Common Bullfrog 



aquatic than any of the other frogs of northeastern North Amer- 

 ica. However, if we happen to be walking across country, or 

 even along a country road during a long-continued heavy rain, 

 we may overtake a large Bullfrog who seems to be making the 

 same journey. Whether the continued wet weather has tempted 

 him to go hunting beyond his usual bounds, or whether he is mi- 

 grating from pond to pond, it would be difficult to say. He 

 proceeds by successive leaps, about three feet each in length. 

 He can cover a distance of five or six feet without difficulty, 

 notwithstanding his large, heavy body. A wet Bullfrog leaping 



i^ 







across a dry surface leaves curious tracks, interesting in that 

 they show how large a part of the under portion of the body 

 and thighs strikes the ground forcibly after each leap, and how 

 the frog " toes in " with its front feet. 



The Bullfrog is our largest frog. (Fig. 277.) He may 

 measure six or seven inches from the tip of the muzzle to the 

 posterior end of the body. A young frog of this species, which 

 had been raised in the laboratory, measured four inches in length 

 on his first birthday. However, size is not a good criterion by 

 which to judge the age of a Bullfrog, or even its identity. The 

 variation in this particular is marvellous. A frog one year old 

 may be no more than two inches long. Much depends on the 

 size attained by the tadpole before the transformation, and of 

 course much also depends on the food and other conditions 

 of the environment, and the ability of the individual frog to cope 

 with these conditions. 



The Bullfrog (Figs. 276 to 278) is very easily distinguished 

 from other frogs, however, whatever may be its size. The head 

 is broad and flat. (The head of the young Bullfrog is relatively 

 less broad than that of the adult.) The ear is much larger than 

 the eye. There are no lateral folds. There is a short fold of 

 skin extending backward from the eye, over the ear, and down 



229 



