Radiotelemetry of body temperatures of free-ranging snapping turtles (Chelydra serpentina) during summer

We wished to determine whether free-ranging snapping turtles (Chelydra serpentina) would use aquatic and atmospheric basking to maintain body temperature at the mean temperature (28–30 °C) selected by snapping turtles placed in a controlled aquatic thermal gradient. Body temperatures from eight adult snapping turtles in three different lakes in Algonquin Provincial Park were monitored by radiotelemetry during July and August 1987. Mean body temperature of all eight turtles over the study period was 22.7 °C, and mean temperature of every individual was well below the reported mean selected temperature for this species. The turtles did not maintain body temperatures near the available maximum environmental temperature. The mean body temperatures of the turtles were not significantly different among the three study lakes although these lakes had different physical characteristics. Similarly, there were no significant differences, among individual turtles, between air temperatures or operative environmental temperatures recorded concurrently with their body temperatures Nevertheless, mean body temperatures differed significantly among individuals; foraging tactics, metabolic rates, and home range structure may account for these differences.