Thermotelemetric study on the hibernation of a common hamster, Cricetus cricetus (Linnaeus, 1758), under natural circumstances

By means of radio-thermotelemetry a study was made of the thermoregulatory patterns during hibernation of a common hamster, Cricetus cricetus (L., 1758) under natural conditions. In the euthermic state, body temperature (Tb) fluctuated between 36.4 and 38.6°C with Tb higher than 37.0°C probably indicating activity. The hamster went into deep hibernation 23 times. The entrance into hibernation lasted 20—60 hours, the state of deep hibernation 17—110 hours and the subsequent arousal 3.5—6.5 hours. Both the duration of arousal and of a bout of hibernation seemed to be negatively correlated with Tb. The euthermic interbout state lasted 4—25 hours. The minimum Tb during deep hibernation ranged between 10.0 and 2.6°C. Sixteen bouts of hibernation could be observed completely with their respective intervals from entrance to arousal. In 11 bouts arousal followed after a drop of the ambient temperature (Ta), in four bouts after a rise of Ta and in one bout at a constant Ta