Thermal-metabolic relationships in hatchling snapping turtles during simulated seasonal cooling

There is limited information available regarding metabolic rates (MR) in many species or life stages of turtles. I measured MR (as O2 consumption) in fasted hatchling snapping turtles (Chelydra serpentina) at 5 to 25 °C.  The relationships between temperature and MR (per capita and per gram wet body mass) were exponential and linearized by Log10 transformations. The relative change in MR over a 10 °C range (Q10) varied with the ranges of temperatures compared and ranged from Q10, 15 to 5 = 3.6 to Q10, 25 to 15 = 9.6 to 9.9, for per capita and per gram values, respectively. The high Q10 values observed here demonstrate reductions in metabolic activity with declining temperatures that are two to three times the predicted value.  Such a strong thermal dependence of MR suggests a rapid response to seasonal changes, facilitating energy conservation during cooling periods and growth during warming periods in this temperate reptile.

Methods
Data are mean values per animal from assays of metabolic rates, measured as oxygen consumption. Data are given in per capita and per gram rates.  Units for temperature = degrees Celcius; Units for wet mass = grams; Units for per capita metabolic rates = ul O2/ minute; Units for per gram metabolic rates = ul O2/ gram minute. Log transformed data were transformed by Log10.