Long-Term Sperm Storage in the Female Neotropical Rattlesnake Crotalus durissus terrificus (Viperidae: Crotalinae)

Abstract

This paper reports tbe muscular twisting and convolution of the uterus in Crotalus durissus terrificus as a strategy to store sperm over winter (long-term sperm storage). Aspects of the female reproductive cycle are reported such as mating season (austral autumn), size of follicles (0.5 to 3.0 em). time of ovulation (austral spring), and gestation period (4 to 5 months). Morphological and physyological changes were observed in tbe uterus of adult females soon after mating. This condition lasted for only one season (austral winter) and after ovulation the uterus relaxed and spermatozoa ascended the oviducts. The anatomy of the genital tract is described and the terminology is discussed in comparison with other temperate relatives (c. viridis viridis). The importance of such physiological procfess is hypothesized as a way to avoid waste of vitellogenic follicles, which are nol ready to be ferlilized at the time of mating. Due to the asynchrony of the reproductive events in this species, long-term sperm storage is an obligatory component .