FROGS BUILDING WALLS 



our solitary craftsman in the present chapter, though his 

 'masonry 1 is nothing more than a rampart or crater of 

 soft mud. 



The animal in question is called by naturalists Hyla 

 faber, and is one of the largest of the tree frogs. Its home 

 is in Brazil, where it is known as the Ferreiro, or smith, and 

 it is quite the genius of its family. During the breeding 

 season the female frog builds regular nests in the shallow 

 margins of ponds and marshes. She dives to the bottom of 

 the water and in her two hands takes up masses of mud, 

 which she places side by side in such a way as to form a 

 circular wall, enclosing a space about a foot in diameter. 

 She continues to build in this manner until the wall gradu- 

 ally reaches the top of the water, and at length stands up 

 for the height of about four inches above the surface, when 

 it has the appearance of a miniature crater of a volcano. 

 The parapet is smoothed most carefully on the inner side, 

 and for this purpose the frog uses its broad, flat hands like 

 trowels. The bottom of the little pond or crater is also 

 made quite even by the under surfac * *he animal's body, 

 aided by its hands. The building ^5 carnta* on during the 

 hours after sunset, when these creatures are most active, and 

 by the end of the second night the nest is completed and 

 quite ready to receive the eggs. It no doubt affords excel- 

 lent protection against their enemies for both the eggs and, 

 later on, the tadpoles. 



The male frog gives no assistance whatever in the prepara- 

 tion of the nest ; both parents, however, usually remain in 

 its vicinity afterwards and appear to keep an eye on it. 



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