Hyperthermic reactions of voles to novel and repetitive psychogenic stimuli

Montane voles (Microtus montanus) respond to brief conspecific encounters with strange voles by adrenergic reactions which result in elevations of their core temperatures by approximately 1.0 degrees C. Elevations of body temperatures and agonistic behaviors decrease in intensity with sequential encounters between the same conspecific challengers but are restored when one of the challengers is replaced by a new "strange" vole. The rates of habituation of agonistic behaviors and of hyperthermic response are a function of the number of encounters permitted, rather than time between encounters. Levels of hyperthermic responses resulting from contact between previously habituated animals are higher than those elicited by non-specific stimuli such as noise or handling. Radiotelemetry of feral animal temperature homeostasis may provide a useful measure of low-frequency social encounters between conspecific voles.