Abstract

The Brazilian rattlesnake (Crotalus durissus terrificus) is distributed all over south and southwestern Brazil. This snake is responsible for 10% of the 20,000 annual snakebites in this country. The aims of this study were to collect and evaluate the semen of the Brazilian rattlesnake (Crotalus durissus terrificus) during a 12-month period. The serum testosterone levels were also studied. Samples were obtained from wild-caught adult males from the Sao Paulo state. It was possible to obtain 112 semen samples and 116 serum samples. The spermogram results are as follows: seminal volume 18.49±2.04 µl, sperm concentration 1.39±0.08x10⁹/ml. The highest value for pleomorphic sperm cells occurred in the winter (42.35±4.18%). The lowest value occurred in the spring (17.67±2.45%). In the summer (spermatogenesis peak) and autumn (mating season), we found intermediate values of 28.72±2.73% and 28.53±1.83%, respectively. The seasonal serum testosterone levels were: 8.89±3.81 ng/ml (winter), 12.09±3.58 ng/ml (spring), 52.6±9.24 ng/ml (summer) and 43.12±8.89 ng/ml (autumn). The results during the mating season and spermatogenesis peak (autumn and summer, respectively) matched with the highest testosterone levels.

Acknowledgments

We thank CNPq, FAPESP.