224 J Snakes and Frogs and Their Relatives 



The Legs and Tail Develop: A tadpole's flat tail, bordered by a 

 fin, is a valuable swimming aid. But in a matter of weeks the 

 time depends on the species the first sign of legs foreshadows the 

 decline of the tail's usefulness. The hind legs appear first as mere 

 bumps but soon push out completely with five webbed toes. 



Meanwhile the front legs show just in back of the head, the 

 left one pushing out through the breathing pore. The front feet 

 have only four toes apiece and are not webbed; they are used for 

 balancing, whereas the back feet serve for thrusting forward. 

 While these changes are taking place, the tail is becoming 

 absorbed by the body. 



First Amphibian Landing: Young frogs do not always wait for 

 the completion of their adult form before venturing on land. In 

 late spring or early summer you may see one hopping about, still 

 wearing its stumpy little tail. From then on the frog is primarily 

 a land animal, though the members of most species stay near 

 water, ready to jump in at a sign of danger or simply to refresh 

 themselves. 



The frog puts its tongue to good use. Hinged to the front of 

 the lower jaw, the tongue can be thrust far out of the mouth to 

 capture insects on its sticky surface. 



BIGGEST AND SMALLEST FROGS 



The bullfrog is the giant among North American frogs. 

 Eight inches is about its maximum length. Its head is usually a 

 bright green, the upper part of its body green also but shading 

 to gray and brown, and its underside is yellowish. 



Other identifying features are its large eardrums and the con- 

 spicuous folds of skin which run from behind the eyes around 

 the eardrums to the front legs. The bullfrog's deep voice is prob- 

 ably better known than its appearance. You may hear its sonorous 

 jug-o'-rum repeatedly near lakes and ponds on summer evenings. 



Just as the bullfrog is a typical "voice of summer," the little 

 tree frog, commonly known as the peeper, might be called the 

 "voice of spring." The spring peeper or, more prosaically, Pick- 

 ering's hyla is one of the tiniest of froglets. Fully grown, it is about 

 an inch long! 



