Effects of core temperature upon duration of hibernation of Citellus lateralis

Abstract

Continuous recordings of core temperatures by permanent thermocouples in 31 golden-mantled ground squirrels (Citellus lateralis) during the hibernating season indicate: 1) hibernating periods persisted longer at lower core temperatures, periods averaged approximately twice as long at 2 as at 11 C; 2) the duration of hibernating periods was relatively constant and predictable for individuals at given temperatures; 3) when two core temperatures were experienced during a single hibernating period and the time spent at each temperature expressed as a per cent of the predicted duration for each temperature, the sum of these percentages approximated 100%; and 4) less stimulus was required to evoke arousal as a hibernating period progressed. Based upon the time-temperature relationship, increased irritability as periods progressed and individual consistency, the termination of hibernating periods (arousal) was thought to be a triggering of the autonomic nervous system by an accumulation or depletion of factors exceeding the limits of the hibernating homeostasis. ground squirrel; arousal; hibernation induction; irritability; partial arousal; stimulus to arousal; homeostasis; thermocouple, permanent implantation Submitted on July 9, 1964