Growth and Age at Reproductive Maturity of the Carolina Pigmy Rattlesnake, Sistrurus m. miliarius (Reptilia: Serpentes).

摘要

Growth and age at reproductive maturity are life history attributes that play an important role in the development of proper management strategies. The Carolina Pigmy Rattlesnake, Sistrurus m. miliarius, is one of two dwarf rattlesnake species. The subspecies ranges from eastern NC to nearly the southern tip of SC, and into the northeastern portion of GA. In NC, where the species' status is of Special Concern, fragmentation and land development has destroyed most of its historic range. Its small size also makes it highly susceptible to predation. In some parts of the range, commercial collection is another pressure the species faces. Carolina Pigmy Rattlesnakes are difficult to study due to their elusive behavior; thus, little is known about their life history. I modeled growth and age at reproductive maturity for a stable population of pigmy rattlesnakes from a wildlife refuge in north-central SC. During a six-year mark-recapture study, I recorded growth intervals (snout to vent length, or SVL) from free-ranging Carolina Pigmy Rattlesnakes. I fit these data to both von Bertalanffy and logistic growth interval models, and used residual error mean square for comparison. The von Bertalanffy model estimated age at reproductive maturity at 2.7 years (males) and 2.1 years (females), and asymptotic size at 46.7cm (42.3-51.5, males) and 45cm (36.4-53.7, females); the logistic model estimated maturity at 3.4 years (males) and 3 years (females), and a total length of 45.2cm (42.1-48.2, males) and 43.9cm (37.7-50, females). These results demonstrate an accelerated life history of Carolina Pigmy Rattlesnakes, especially when compared to other pit vipers. An understanding of these aspects of their life history is essential to a sound management plan.