Survivorship of adult females in a northern population of common snapping turtles, Chelydra serpentina

Survivorship of adult female snapping turtles (Chelydra serpentina) in a marked population in Algonquin Provincial Park, Ontario, was estimated using recapture records and catch-curve analysis of age structure. Known mortality was less than 1% per year, and a 13-year average of survivorship was 96.6% per year. Even the conservatively biased catch-curve estimate (92.9% per year) was among the highest yet reported for any turtle population. We compared two hypotheses to account for these high values. Although not at variance with our results, we rejected Rubner's proximal "rate of living" hypothesis because of lack of any other evidence that this process operates in reptiles. The second hypothesis was that high survivorship was the consequence of specific demographic features in a bet-hedging life-history strategy. Females would be more successful, given the high and stochastic clutch mortality and lack of predation on adults in this northern population, if they produced smaller clutches over many years than if they produced larger clutches over fewer years. This suite of characteristics may have allowed for the establishment of this northern population, or the high survivorship of adult females in this population may be an evolved response in the direction predicted by bet-hedging theory.