36 



BREEDING HABITS OF AMPHIBIA 



The male has a yellowish throat but also a yellow spot or ring xn the center ol its tym- 

 panum, and its head is wider than that of the female. Breeding occurs in quiet, shallow 

 plant-grown ponds from May to August, generally in late June and early July, even in the 

 same latitude and environment. The eggs may number as many as 5, 000 and they are 

 approximately the size of those of Rana pipiens, 1. 5 mm. in diameter. The eggs and 

 tadpoles can tolerate a low oxygen environment, the tadpoles generally hibernating in mud 

 for one winter and then quickly passing through metamorphosis in early Spring at 370 to 

 400 days. Low temperatures are disastrous, the embryos being unable to survive 10 C. 

 The time lapse from stage #12 to gill circulation at 15°C. is about 220 hours. 



) ;■• '' 



Typical amplexus of 

 Rana clamitonsj lateral 

 view. 



Egg-laying posture of Upstroke of the male Downstroke of the male 



Rana clamitans just Rana clamitans and Rana clamitans and 



prior to the onset of the appearance of the the formation of the 



the oviposition; first batch of eggs; surface film; dorsal 



dorsal view. dorsal view. view. 



(From Aronson 1943: Am. Mus. Nov. #1224. Artist Mr. M. Sorensen) 



RANA PALUSTRIS . the pickerel frog. This is also known 

 as the Spring Leopard Frog, and is found largely in the 

 East, in sphagnum bogs or in cool clear water surrounded 

 by high grass and other vegetation. The adults rarely 

 exceed 3 inches in body length. 



The color is light brown with numerous squarish dark spots 

 with dark borders, arranged largely in two rows between 

 the lateral plicase which run posteriorly from the eyes. 

 The underside of the legs is bright yellow or orange. The 

 thumb pad of the male is unusually large. 



These frogs breed in late April and in May, the 2, 000 bright 

 yellow eggs measuring about 1. 6 mm. in diameter. The 

 water temperature is generally between 60° and 65°F. , and 

 development is normal between 46°F. and 86°F. The eggs 

 hatch in about 2 weeks, the tadpole reaches a length of about 

 3 inches and metamorphosis occurs in about 80 days. Under 

 laboratory conditions of 15°C. temperature, it takes 200 

 hours to go from stage #12 to gill circulation. Development 

 is slightly faster than that of Rana pipiens. 



Rana palustris, the 

 pickerel frog, as 

 seen from obove. 



(Courtesy C. H. Pope 

 1944: Chicago Mus. 

 Nat. Hist.) 



