DISCUSSION II - MECHANISMS OF THERMAL TOLERANCE IN NON-HIBERNATING ENDOTHERMS

Abstract

Mechanisms of thermal tolerance to cold have been investigated primarily in laboratory animals. The question now, is whether or not these mechanisms are “universal,” thus extrapolation of these findings to other animals can be made without debate. Limited studies on acclimation and/or acclimatization of wild small animals suggested that extrapolation of available data must be made with caution. Physiological strategies and dicotomy of thermal tolerance to cold can be better understood with additional studies using wild animals and simulating field conditions. In other words, continuous exposure (24 hr) to cold may result in physiological responses that are peculiar to this type of cold stress. Still open to investigation is the role of the kidney, the gastrointestinal tract, and the immune response in physiological adaptations to cold. Additionally, further work on physiological and biochemical responses of large arctic animals to heat is urgently needed, since these animals may suffer from overheating during migration in winter or during the summer season.