The Herpetological Journal

pp. 31-39
Authors: Nunes, Simone de Fátima; Kaefer, Igor Luis; Leite, Pedro Terra & Cechin, Sonia Zanini

Abstract: Dissection of preserved specimens of Rhinocerophis (previously Bothrops) alternatus, combined with data on captive individuals, provided information on the reproductive biology, sexual dimorphism and feeding habits of this viperid snake, forming the first comprehensive study on the natural history of this species in subtropical Brazil. Females were longer than males in snout–vent length (SVL), averaging 992 mm. Males averaged 664 mm in SVL and had relatively longer tails. Mating was observed in July under conditions of captivity. Mature males were found throughout the year, as were females with enlarged follicles. Nevertheless spermatogenesis, inferred by an increase in testicular volume, occurred during the early mating period and its preceding months. Oviductal embryos were recorded only from November to January and parturition occurred from February to August, characteristics of a seasonal reproductive cycle, a recurrent pattern for snakes from the subtropical domain. We observed asynchrony in the timing of mating and parturition, indicating long-term sperm storage after mating by females. In addition, our observations of muscular contraction and the presence of spermatozoids in the posterior portion of the uterus of mature females allowed us to suggest utero-muscular twisting as a possible mechanism used by R. alternatus for controlling the timing of its reproductive cycle. The number of newborns per litter varied from five to 20 (mean = 12). Feeding frequency was 29.7%, and the analysis of gut contents indicated a highly specialized diet, which is restricted to rodents (Muridae and Caviidae) and marsupials (Didelphidae). Most of the prey was ingested head-first.

Keywords: VIPERIDAE, BOTHROPS, DIET, REPRODUCTION, MORPHOLOGY, SERPENTES