BREEDING HABITS OF AMPHIBIA 



55 



The color ia light hrown with numerous squarish dark spots with 

 dark horders, arranged largely in two rows hetween the lateral 

 plicase which run posteriorly from the eyes. The underside of the 

 legs is hright yellow or orange. The thumb pad of the male is un- 

 usually large. 



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

 yellow eggs measuring ahout 1.6 nan. in diameter. The water tempera- 

 ture is generally between 50° and 65°F., and development is normal 

 between h-6'^T. and 86°F. The eggs hatch in about 2 weeks, the tad- 

 pole reaches a length of about 3 inches and metamorphosis occurs in 

 about 80 days. Under laboratory conditions of 15°C. temperature, 

 it takea 200 hours to go from stage #12 to gill circulation. De- 

 velopment is slightly faster than that of Hana pipiens. 



nana palustris, the 

 pickerel frog, as 

 seen from above. 

 (Courtesy C. H. Pope 

 I9I+I+: Chicago Mus. 

 Nat. Hist.) 



It is found in al- 



BANA PIPIENS, the leopard frog. This is the common leopard frog 



most frequently used in our laboratories. 



most all parts of the United States and parts of Canada and 

 Mexico. The adults rarely exceed h- inches in body length (96 

 mm. ) but females must be 72 mm. or longer before they can be 

 considered sexually mature. The general color is green with 

 light dorsal plicae. The rounded dark spots on the skin have 

 light colored borders. The underside is white. The male is 

 darker and smaller than the female, with firm abdominal muscles, 

 lateral cheek pouches when croaking, and prominent thumb pad. 

 These frogs are omnivorous feeders and difficult to maintain ae 

 adults in the laboratory except under conditions simulating 

 hibernation when they can go for long periods without food. 

 The newly metamorphosed frogs may be fed earthworms cut into 

 1 inch lengths. These segments of worm will continue to move 

 and thus attract the frogs. 



Male Rana pipiens (the 

 leopard frog) with vo- 

 cal sacs Inflated, as 

 seen from above. 



(Courtesy C. H. Pope 

 19kk: Chicago Mus. 

 Nat. Hist.) 



These frogs breed from March to May depending upon the 

 latitude in which they are found. They lay about 5,000 eggs 

 (diameter about 1.75 nim. ) which generally reach metamorphosis 

 dui'ing the summer. The span from fertilization to hatching Is about 8 days and to meta- 

 morphosis (in the laboratory at 25°C. ) Is about 75 days. The eggs are normally layed In 

 water at about 15°C. and the upper limit of temperature tolerance la about 31°C. Leopard 

 frogs have been known to live for 5 years. 



Iholomus 



End of ovlpositlon. Tlie 

 male, about to release, 

 is sliowing the pre- 

 release movements. Note 

 the female (beneatli) 

 shapiiif!; the eggs into a 

 clump . 



(From Aronson 1914-2: Bull. 



Am. Mus. Nat. Hist. 80:127; 



nucleus N.n 



tegmentum 

 tiypottialomus { 



pars ventralls 



WARNING CROAK [ 



SRftWNING MOVEMENTS 

 ^ RELEASE 



olfoctory bulb 

 cerebrol twmispliere 

 preoptic Oreo 



SWIMMING RESPONSE 



Diagrammatic sagittal section tlirough tlie brain of Rana 

 pipiens Indicating the regions of tlie brain that were 

 found to be of primary importance for tlie mediation of 

 each of four phases of sexual behavior. 



(From Aronson l^k-^: Bull. Am. Museum Nat. Hist. 86:89) 



