HIBERNATION OF THE HEDGEHOG (ERINACEUS-EUROPAEUS L) IN ITS NATURAL-ENVIRONMENT - BIOTELEMETRIC STUDY OF BODY-TEMPERATURE

The timing of hibernation and the duration and depth of hibernation bouts are described in adult male hedgehogs in western France. Previous studies on free living hibernators are lacking. A radiotelemetry system was developed for simultaneous detection, without disturbance, of the location of the animal and continuous recording of its body temperature (Tb). The system comprises a temperature-sensitive transmitter surgically implanted into the abdominal cavity, and a receptor associated with an autonomous station, for the acquisition and storage of data. With regard to Tb variations, hibernation can be divided into three phases: (1) the pre-hibernation phase (from September to mid-October) characterized by short spontaneous bouts of hypothermia (less-than-or-equal-to 12 hrs.); (2) the hibernation phase (from October to January) when the duration of deep hibernation bouts progressively increased (maximum length 10-12 days in December-January), and the depth of Tb during hypothermia decreased (from 15-18-degrees-C in October to 1.5-3.0-degrees-C in December-January); these deep hibernation bouts alternated with short spontaneous arousals and euthermic states (ranging from 2 days in October to 6-7 hrs. in December-January); (3) the end of hibernation occurred between the end of January and mid-February. These studies make it possible to estimate, in the hedgehog, the energy expenditure associated with the different phases of hibernation and to take into account the importance of individual variations.