Thermal environment for overwintering hatchlings of the painted turtle (Chrysemys picta)

摘要

We monitored temperatures during the winter of 1995-1996 inside 18 nests containing hatchling painted turtles (Chrysemys picta). The study was performed at the Valentine National Wildlife Refuge in north-central Nebraska to assess survival of neonatal turtles in relation to the thermal environment inside their hibernacula. Minimum temperatures in the nests varied from -3 to -21 degrees C, and were better predictors of survival of hatchlings than other measures of the thermal environment. All hatchlings survived in nests where the temperature never went below -7 degrees C, some animals survived in nests where the minimum was between -7 and -13 degrees C, but no turtle survived in a nest where the minimum was below -14 degrees C. Hatchlings probably survived the cold by sustaining a state of supercooling, because the duration of exposure to low temperatures was far too long for animals in most nests to have survived in a frozen state.