SEX RECOGNITION AND THE MATING BEHAVIOR 

 OF THE WOOD FROG, RANA SYLVATICA. 



ARTHUR M. BANTA. 



During the last three seasons while collecting amphibian eggs 

 for use in some experimental work the writer had opportunity 

 incidentally to observe some interesting behavior of the wood 

 frog, Rana sylvatica. Inasmuch as the mating behavior and sex- 

 recognition of this frog appear not to have been described in any 

 detail it seems worth while to publish a digest of the rather 

 extensive notes made during the times of observation. 



Miss Hinckley 1 has reported some observations on the egg 

 laying and incidentally refers to the activity and "quacks" or 

 croaks of the males at the mating season. She gives some inter- 

 esting temperature observations, stating that when the air tem- 

 perature is 45 F. there is little activity of the frogs but that they 

 float on the surface "like dead leaves," but that they spawn at 

 50 and that at 52 they are "active and clamorous." The 

 mating season evidently begins earlier at Milton, Mass., where 

 her observations were made, than at Cold Spring Harbor, for 

 in 1880 she observed the frogs at ponds on Feb. 28 and in 1881 

 saw eggs and the quacking males on March 8. 



Wright 2 describes the appearance of the eggs and gives the 

 season at Ithaca, N. Y., as April I to 30. 



The pond at which the writer mainly observed these frogs is 

 perhaps 100 by 40 feet. It was formerly part of an artificial lake 

 from which it was cut off by a grade intended for a railway. 

 In the years since the grade has been abandoned the "Cut-off 

 Pond" has become much filled up with leaves and other debris, 

 so that now it is shallow, largely filled with leaves and much 

 encroached upon about the margin. 



1 Mary H. Hinckley, "Notes on the Development of Rana sylvatica Leconte," 

 Proc. Bost. Soc. Nat. Hist., Vol. 22, pp. 85-95, 1882. 



2 Albert Hazen Wright, "The Anura of Ithaca, N. Y.: A Key to their Eggs," 

 BIOL. BULL., Vol. 18, pp. 69-71, 1910. 



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