Mechanisms of Social Thermoregulation in Hibernating Alpine Marmots (Marmota marmota)

Abstract

Group-hibernating Alpine marmots maintain close body contact to other group members during both deep torpor and euthermic intervals. Analyzing telemetrically recorded body temperature (T_b) profiles of 64 free-living marmots we found that rates of heat loss were independent of individual body mass. Serial correlation coefficients for pairwise comparisons of T_b patterns indicated that the time course of changes between torpor and periodic arousals was generally well synchronized within groups, with territorials arousing significantly earlier than other group members. The degree of group synchrony was the most important factor influencing winter mass-loss. However, group synchrony was impaired in the presence of juveniles. Juveniles frequently displayed delayed warm-ups and appeared to passively gain heat from close body contact to warmer adults. While reduced group synchrony is disadvantageous for adults, it can be calculated that juveniles have a net energetical benefit .