Specific dynamic action, postprandial thermophily, and the impact of temperature on gastric digestion in the cornsnake Pantherophis guttatus

Abstract

The purpose of this work was to study the role of feeding on the energetics of cornsnakes. We measured oxygen consumption in cornsnakes prior to a meal and 6, 15, 20, 30, 40, 48, 72, and 96 h after eating a meal that was equivalent to 10% of the snake's body mass. We monitored temperature selection of individual cornsnakes in a thermal gradient in the spring and again in the fall when snakes were starved, digesting a meal equivalent to 10% of its body mass, and digesting a meal equivalent to 25% of its body mass. We measured the gastric digestion rate by monitoring the passage of magnetic stir bars, placed inside a mouse meal, through the digestive tracts of cornsnakes maintained at 22°C, 25°C, 28°C, and 32°C. Oxygen consumption peaked at 2.3 times higher than baseline levels 24 h after feeding and had returned to pre-feeding levels by 72 h. Meal size affected temperature selection in both seasons; in fall, starved snakes selected lower body temperatures than fed snakes, but meal size had no effect on temperature selection by fed snakes. Passage rates from the stomach to the intestine did not significantly differ among the temperatures studied.