Ecology of the snapping turtle,
Chelydra serpentina, in northwestern Florida

Matthew J. Aresco¹ and Margaret S. Gunzburger²

¹Department of Biological Science, Florida State University, Tallahassee, FL 32306-1100
²United States Geological Survey, Florida Integrated Science Center, Gainesville, FL 32653-3701

Presented at the 2005 Joint Meeting of Ichthyologists and Herpetologists, Tampa, FL, 6-11 July 2005.

Background

Chelydra serpentina, the common snapping turtle, is one of the largest and most widely distributed turtles in North America.  Life-history and demography of C. serpentina are relatively well-studied in some areas in the northern portion of its range, and research indicates that this species has a typical life history of a long-lived ectothermic vertebrate: slow growth rate to maturity, low egg and juvenile survivorship, low recruitment, and high adult survivorship.

Chelydra serpentina osceola, pointed neck tubercles, Marion Co., FL Photo courtesy of Steve Johnson, UF

Objective

To collect baseline ecological data for C. serpentina from the southern portion of its range, in the Florida panhandle.

C. s. serpentina x C. s. osceola intergrade, intermediate neck tubercles, Leon Co., FL

Methods

We sampled C. serpentina at 5 localities in Leon Co. FL from 1999-2004 using various collection techniques, including hoop traps and hand collecting (n=112).  We also recorded data for C. serpentina that we encountered incidentally at other localities (n=11).

Population Structure & Demography

Taxonomy

Analysis of seven morphological characters in 35 individuals indicates that C. serpentina in Leon Co. FL are C. s. serpentina x C. s. osceola intergrades.

Growth rate

Estimated early growth rate (age 1-6 yr) of C. serpentina ranged from 20-30 mm CL/yr. Females mature in 6-8 yr, males mature in 4-6 yr.  Males are larger than females.

Reproduction

Clutch size ranges from 5-49 eggs; nesting occurs from early April to late May (n=3).  Sex ratios were 1:1.

Conclusions

C. serpentina abundance and biomass are highest at small, suburban ponds and lowest in large lakes.

Juvenile recruitment is low; populations are dominated by large adults.

Size at maturity is similar between populations in Florida and in the northern portion of the species range, but growth rates are higher in Florida.

C. serpentina populations are threatened by habitat alteration, including wetland sediment removal operations, habitat fragmentation, and unregulated harvest.