Growth, sexual maturation and body size dimorphism in the Indian bullfrog, Hoplobatrachus tigerinus (DAUD)

Abstract

The pattern of growth, age and size at sexual maturity, and sexual size dimorphism were determined for 30 Indian bullfrogs, (Hoplobatrachus tigerinus) reared in out-door terraria, from metamorphosis to 3 years of age. Size and the growth rates for males and females were comparable throughout the study. For SVL, annual mean growth rate was very high in the first year (7.31 cm) but declined in the 2^nd (2.70 cm) and 3^rd (0.53 cm) years. For body mass, annual mean growth rate was similar (∼68 g) for the 1^st and 2^nd years but declined (24.31 g) in the 3^rd year. In general, growth was faster during summer than in winter months. After attaining maturity, growth rate declined for both sexes. Some males attained sexual maturity in the first year (10 months old), while the remaining males and all females matured at the end of 2^nd year. In naturally occurring breeding populations, males tend to be smaller than females. This difference appears to be due to the presence of males and females of different age groups rather than differences in early growth rates.