Is Longevity Related to Body Size or Behavior in a Hatchling Turtle

Abstract

Adequate knowledge of life history patterns is crucial when evaluating conservation options of declining species. Data often exist for adult animals, which are usually more visible in the environment and thus easier to study. However, hatchling and juvenile animals are critical to maintaining recruitment into a population, and data on these life stages are often lacking. We investigated the manner by which body size and behavior of hatchlings affect longevity (days) in a terrestrial turtle, Gopherus polyphemus , living in a protected habitat in Florida, USA. Survival was not related to body size, activity, or movement patterns and the occurrence of hatchlings killed by predators seemed random. Body size was consistent within, but not among clutches. However, variation in behavior and longevity was consistent among, but not within clutches. Thus, it appears that individual female tortoises are producing offspring of consistent size, with different behavioral traits that also differ in longevity (during the first year of life). These findings demonstrate the importance of individual female gopher tortoises to the stability and growth potential of a population because all females seem capable of producing offspring varying in longevity over short time-scales (<1 year). However, because all hatchlings in this study were depredated during their first year of life, the relationship between patterns of longevity in juvenile animals and population dynamics in long-lived species deserves further attention.