Wood Frog Life History 



37 



Table 1. Body and ovarian weights (g) and ovarian weight as a percentage of 

 body weight for adult female Rana sylvatica collected in Alabama at 

 different times of the year. 



Date 



Body weight 



Ovary weight 



Ovary weight 



as pecentage 



of body weight 



3 September 



22.4 



3.3 



14.7 



29 September 



38.4 



3.7 



9.6 



12 November 



24.9 



3.1 



12.4 



12 November 



20.4 



2.9 



14.2 



23 November 



31.3 



4.3 



13.7 



23 November 



27.4 



4.0 



14.6 



23 November 



29.1 



4.8 



16.5 



17 January 



52.0 



21.7* 



41.7 



(female in breeding pond) 







18 January 



10.5 



0.6 



5.0 



(spent female) 









18 January 



17.6 



0.7 



3.9 



(spent female) 









14 May 



13.2 



0.7 



5.3 



* ovisac weight 









body weight, an extended period is probably necessary for a female to 

 reach reproductive condition. Redshaw (1972) reported that amphibian 

 oocyte enlargement from 450/i to 1400/i required a period of 9 months. 



Sexual Dimorphism, Calling, and Amplexus 



Sexual dimorphism is more pronounced during the breeding sea- 

 son. Males are generally much darker than females, the ground color 

 ranging from deep brown to almost black. Howard (1980) noted that 

 this darker color matched the dark color of the water in breeding ponds. 

 Females are usually tan to reddish brown during the breeding season. 

 Darker females are observed occasionally, but they are never as dark as 

 males. The margin of the toe webbing between the digits of the hindlimb 

 is markedly convex in males. The male thumb (first digit on the fore- 

 limb) and the musculature in the forelimb are also enlarged during this 

 time, as in other ranid species. Noble and Farris (1929) thought that the 

 additional surface area provided by convexity of the toe webbing 

 allowed males more mobility in the water, a suggestion consistent with 

 the behavior of males during the breeding season. The thumbs of male 



