Townsend voles responded to each other by raising their core temperatures. 2. Increments of temperature increases that accompanied hostile reactions between voles, were proportional to the intensity of the behavioral displays. 3. Amicable behaviors (huddling) were also associated with higher body temperatures that were proportional to group size. 4. Huddling voles conserved metabolic energy expenditure by reducing their metabolic rates and thermal conductances. 5. Such conservation required 1 or more days of amicable behavior to develop, and to be reversed. 6. The degree of metabolic rate reduction that accompanied amicable huddling behavior and the associated reduction of thermal conductance was independent of group size.
