Physiological aspects of overwintering in the boreal chorus frog ( pseudacris triseriata maculata)

Abstract

1. 1. Total body water content and plasma osmolality of frogs captured in April and August and acclimated to various combinations of temperature and photoperiod were determined. 2. 2. Total body water content appeared to remain stable while plasma osmolality decreased with declining acclimation temperatures. Photoperiod had no effect on either of these variables. 3. 3. Seasonally, August frogs had a reduced total body water content and greater mean plasma osmolality than April frogs. 4. 4. April frogs supercooled to −3.0 C.