Thermoregulation and water requirements in semiarid and montane populations of the least chipmunk, Eutamias minimus—III. Acclimatization at a high ambient temperature

Abstract

Abstract 1. Acclimatization at 34°C results in a reduction of metabolism, body temperature (Th), and evaporative heat loss (EHL) and an increase in dry heat conductance as compared to values reported for chipmunks acclimatized at 22°C. 2. At high ambient temperatures, the semiarid population, as compared to the montane population, maintains a lower Th under all conditions examined. The lower Th occurs because of a higher EHL when water is available and because of reduced metabolism when dehydrated. 3. Adaptation of E. minimus to the semiarid habitat has involved changes in response to acute and chronic heat and water stress which increase the time the chipmunks can survive exposures to high ambient temperature, regardless of water availability.