BEHAVIOR AND COLOR CHANGES OF TREE FROGS 



CHARLES W. HARGITT 



From the Zoological Laboratory of Syracuse University 



INTRODUCTORY 



Concerning the general facts of the life history, behavior, 

 etc., of amphibia as a class much is well known. The admirable 

 " Frog Book," by Miss Dickerson ('06) has made available a 

 splendid body of information concerning " North American 

 Toads and Frogs," and a similar service has been rendered by 

 Boulenger ('98) in the " Tailless Bactrachians of Europe." But 

 admirable as these are for the general student, they leave much 

 to be desired in the way of detailed scientific investigation. 

 This is particularly the case with phases of behavior, color 

 changes, development, etc. 



In the following account I have sought to bring together 

 the results of observations and experiments touching facts of 

 behavior and color changes in two species of tree frogs, Hyla 

 versicolor and H. arborea; the former, the common tree frog of 

 eastern North America, the latter the equally familiar tree frog 

 of Europe. My study of Hyla arborea has been limited to 

 about two months, and was done at Naples. In the case of 

 H. versicolor my observations cover a period of several years, 

 though at such incidental times as made it convenient and 

 practicable. As will be seen, these studies include both field 

 and laboratory work, especially of the American species, and 

 I have made the field work emphatic wherever at all practicable. 

 I have elsewhere ('09, p. 157) emphasized the crying need for 

 larger attention to this phase of experimental work, believing 

 that in many cases it is all but impossible to secure trustworthy 

 results as to behavior of animals where the work has been done 

 under such unusual, unnatural and artificial conditions as 

 most laboratory provisions afford. 



What right has one to assume that the actions of an animal 

 taken rudely from its natural habitat and as rudely imprisoned 

 in some improvised cage are in any scientific sense an expression 



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