Comparative Ecology of Two Species of Semiaquatic Snakes in Southeastern North America

Abstract

The banded water snake (Nerodia fasciata fasciata) and the Eastern cottonmouth (Agkistrodon piscivorus piscivorus) were the focal species in a long-term mark and recapture study in the upper coastal plain of South Carolina, USA. Recapture rates were low for both species. Female N. fasciata were significantly larger than males. Male A. piscivorus were larger than females but not significantly. Age structure and sex ratios were determined for these populations. Recapture latency was greater for A. piscivorus than for N. fasciata. There was little dietary niche overlap between these two species. Nerodia fasciata ingested significantly more fish headfirst and more amphibians tail first. Growth rates were also calculated for both species. Litter size, offspring size, relative clutch mass and parturition dates were determined for N. fasciata.