BREEDING HABITS OF AMPHIBIA 



43 



Breeding occurs in the Fall following an elaborate courtship at the breeding grounds 

 which are on the edge of dry pond beds. Spermatophores are picked up by the female and 

 she proceeds to deposit singly from 100 to 250 eggs in a nest which is nothing more than 

 a depression under moss or a log. The duration of the pre-hatching stage depends en- 

 tirely upon the rainfall and may not occur until Spring. The adults can drown but the 

 larvae require the Fall rains to hatch. The eggs withstand desiccation but shrink as they 

 dry. They hatch at about 70°F. and mature about 15 months later. 



AMBLYSTOMA PUNCTATUM , the spotted salamander formerly known as A. maculatum. 

 This is the most common of the large American salamanders and is found in the Eastern 

 United States. There are two irregular rows of bright orange spots along the back. The 

 background color is bluish black. The males have dark bellies and protruding vents. 



Breeding occurs immediately after the Spring thaws, and there is a brief courtship on 

 the part of the male before it drops up to 40 spermatophores, in shallow water. The 

 water temperature may be as low as 13 C. The females pick up the spermatophores 

 with their cloacal lips and proceed to lay from 100 to 200 eggs in semi-solid clumps of 

 jelly about 6 inches below the surface, often attached to a stick or stem. The jelly is 

 sometinnes opaque, but the embryos are normal. The jelly masses lie freely in the water. 



Typical egg clusters of spotted 

 salamander as they appeared on 

 April 9. A spermatophore can 

 be seen on leaf below large 

 cluster. (After Bishop) 



Spermatophores of spotted salamander in situ 

 on April 14. Inset: A single one, greatly 

 enlarged. (After Bishop) 



(Courtesy C. H. Pope 1944: 

 Chicago Mas. Nat. History) 



These eggs will tolerate refrigerator temperatures as low as 4°C. and if kept at such low 

 temperatures the time to gastrulation may be extended to about 10 days. The optimum 

 temperature for development is between 12°C. and 15°C. , but the embryos will tolerate 

 20 C. at the upper limit. At 10°C. the embryos pass from stage #7 to stage #25 in about 

 300 hours (13 days). These are excellent eggs and embryos for operative procedures. 



AMBLYSTOMA TIGRINUM , the tiger salamander. This salamander is found throughout 

 the United States and in Canada and Mexico. There are numerous yellow spots which 

 cover the body but are largely concentrated along the sides of the belly, in contrast with 



