Ecology and Morphology of Chelydra serpentina in Northwestern Florida

Abstract

Chelydra serpentina (Common Snapping Turtle) is a wide-ranging and often abundant turtle species in the eastern United States, but relatively little is known of its basic ecology in the Southeast. The objective of our study was to examine the ecology and population biology of and describe the morphology of Common Snapping Turtles in northwestern Florida. We intensively sampled five localities in Leon County, FL using traps and hand collection (n = 111), and we also opportunistically collected Common Snapping Turtles as we encountered them through the course of other studies (n = 11). Analysis of seven morphological characters from a subset of individuals indicated that the Common Snapping Turtle in this study is an intergrade between C. s. serpentina and C. s. osceola. Estimated early growth rates were 20 mm carapace length (CL)/year, and females matured at about 220 mm CL (156 mm PL, approximately 6–8 years). Male Common Snapping Turtles (CL mean = 299 ± 6 mm) were larger than females (CL mean = 270 ± 5 mm), and the overall adult sex ratio was 1:1. Diet consisted primarily of aquatic plants (n = 4). Nesting females were found from early April through mid-May, and clutch size ranged from 5 to 49 eggs (n = 3). Common Snapping Turtle abundance varied over the five sites, but was highest (an average density of 16 individuals/ha) in small suburban ponds with abundant aquatic vegetation, a thick layer of organic sediment, and no alligators. In northwestern Florida, predation by alligators and humans and primary productivity appear to be the factors that influence the distribution and abundance of Common Snapping Turtles.