NOTES ON THE NATURAL BREEDING HABITS OF SOME 



COMMON AMPHIBIA 



. Natural breeding on the part of different species of the Amphibia covers all the sea- 

 sons of the year, in the various latitudes. The one characteristic feature of all but a 

 very few specialized forms is that breeding occurs in or near water regardless of the 

 habitat during the balance of the year. In general, the Amphibia lay their eggs and then 

 desert them. This means that there is a very high mortality and in order to survive, the 

 race must produce a great excess of eggs. It has been estimated (Smith: Science 19'+?, 

 V. 105, P« 619) that the maximum number of eggs layed by any amphibian species is probably 

 in the neighborhood of 55,000. It is interesting that the high numbers are layed by the 

 predominantly aquatic Anura while among the Urodela the number of eggs layed may be less 

 than 100, in certain species. The aquatic environment is apparently the more hazardous 

 when compared with the mildly damp environment where one occasionally finds Urodele eggs. 



Regarding the insemination of the eggs, the frogs shed their products into the water 

 simultaneously during amplexus; many of the toads similarly shed their gametic products 

 but the eggs are layed In strings and the male Inseminates each egg as it eioerges from the 

 cloaca. Finally, among the Urodela it is necessary for the female to pick up spermato- 

 phores and to take them into her cloaca and genital tract where the eggs are fertilized 

 before being layed. Thus there is considerable variation in the breeding procedure among 

 the various species of Amphibia. 



There are a number of forms which, because they are relatively common, are likely to 

 be available for use in our laboratories. For this reason there Is presented below a 

 table showing the common name, location, breeding periods, and egg production of these 

 forms. 



BREEDING HABITS OF SOME COMMON AMPHIBIA 



Animal 



Popular Name 



Locality 



Breeding # ^gs 



FBOGS 



ACRIS GRYLLUS 

 HYLA CRUCIFER 

 HYLA VERSICOLOB 

 PSEUDACEIS NIGBITA 



RAKA CATESBIANA 



BANA CLAMITANS 

 EANA PALUSTBIS 

 SANA PIPIENS 

 EANA SYLVATICA 



Cricket frog 

 Spring peeper 

 Tree frog 

 Swamp tree frog 



Bullfrog 



Green frog 

 Pickerel frog 

 Leopard frog 

 Wood frog 



Central U.S. 

 Eastern seaboard 

 Eastern U.S., Canada 

 All U.S. except N.Eng. 



East of Bockies 



Eastern N. America 

 Eastern N. America 

 Entire U.S. 

 Entire U.S. 



May to July 



April 



May and June 



March and April 



May to August 



June to August 

 April and May 

 March to May 

 March to May 



Few 



1,000 

 50 



500 to 



1,500 



6,000 to 



20,000 

 5,000 

 2,000 

 5,000 

 5,000 



TOADS 



BUFO AMERICANUS 

 BUFO FOWLERI 

 XENOPUS LAEVIS 



American toad 

 Fowler's toad 

 African clawed-toad 



Northeastern U.S. 

 Central & East U.S. 

 South Africa 



April and May 

 April to June 

 April to Sept. 



6,000 



8,000 



15,000 



SALAMANDEBS 



AMBLYSTOMA 



JEFFERSONIAMJM 

 A. OPACUM 

 A. PUNCTATUM 



(MACULATUM) 



Jefferson 



salamander 

 Marble salamander 

 Spotted salamander 



East U.S., South 



Canada 

 East & Middle West 

 Eastern U.S. 



Early Spring 



Sept. to Oct. 

 January to May 



500 



100-250 

 100-200 



-50, 



