The Herpetological Journal

AUTHOR: Malcolm W. Kennedy

ABSTRACT: Using non-contact infrared thermometers, the surface temperatures of freshly laid eggs of sea turtles were measured as proxies of core body temperatures while they were nesting. Data were accumulated over seven consecutive nesting seasons for two species with contrasting lifestyles – leatherbacks Dermochelys coriacea, the largest, which are anatomically adapted to migrate between tropical breeding sites to cold temperate waters, and the smaller hawksbills Eretmochelys imbricata that are generally confined to the tropics and sub-tropics. Leatherbacks ranged between 28.7 °C and 32.5 °C (30.9 °C ± 0.6 °C; mean ± standard deviation) and hawksbills 26.3 °C to 32.0 °C (29.2 °C ± 0.8 °C), with year-to-year variations in temperatures in populations of both species (year mean 30.4 °C to 31.5 °C in leatherbacks), hawksbills the more so (28.1 °C to 30.3 °C). These differences will likely be modified by both natural seasonal variations, anthropogenic changes in ocean temperatures and variabilities in currents and water temperatures local to nesting beaches. Such diversities in body temperatures of nesting turtles are pertinent to predicting environmental tolerances, reproductive success and nest site selection, and could contribute to predicting which rookeries may remain viable or not as oceans warm.

Keywords: Dermochelys coriacea, Eretmochelys imbricata, core body temperatures, egg surface temperatures, oviposition