Experimental analysis of body size and shape during critical life-history events of hatchling slider turtles, Trachemys scripta elegans

1. A fundamental goal of examining life-histories is to identify those traits that enable organisms to move from one stage of life to another; however, traits that are important in one stage or event may not be important in subsequent cases. For long-lived taxa like turtles, studies of early life stages might be especially revealing because mortality is high during those times. 2. In this study, we examined several morphological characters in hatchling turtles to assess their relationships with hatchling performance and survival. We assessed hatchling plastron shape and body size during a release–recapture field experiment and in subsequent swimming performance trials in the laboratory. 3. Hatchling mass and plastron shape were correlated. Heavier turtles were relatively shorter and wider than lighter turtles. 4. Hatchling mass had a significant positive correlation with both recapture rate, a proxy measure of survivorship, and with swimming speed. 5. Plastron shape and recapture probability were not significantly correlated, but shape was a significant predictor of swimming performance. Shorter, wider turtles swam faster than longer, skinnier individuals. We hypothesize that this may be advantageous for quick-start swimming to escape predation, a function of longer legs, or improved range of motion. 6. These data support previous studies that demonstrated the importance of hatchling size for survival in the critical overland migration from nests to the water and also document the impact of body shape on basic life-history traits for neonatal turtles.