Regulation of arousal from hibernation by temperature in three species of Citellus

The frequency of arousal from periods of hibernation of Citellus lateralis, C. tridecemlineatus, and C. columbianus was demonstrated to be regulated by environmental (and therefore body) temperature over the range of 2-12 degrees C in a log-linear relationship. The slopes of the lines of regression for all three species were not significantly different from one another. Durations of the periods of hibernation for the considerably larger C. columbianus, however, were significantly longer at all levels of temperature than those for the similar-sized C. lateralis and C. tridecemlineatus. The mechanism(s) regulating the duration of the period of hibernation was considered to be concerned with some aspect of metabolism and probably the same for all three species.