Ritmi circadiani e comportamento di un gruppo di marmotte alpine (Marmota marmota) in ibernazione. Rhythm and behaviour in a group of hibernating alpine marmots [Rythme et comportement dans un groupe de marmottes hibernantes].

Résumé

Three adult Alpine Marmots (Marmota marmota) were studied, during winter 91, in a dark room under constant ambient temperature (8°C). Behaviour and skin temperature were continuously recorded, during the whole period. Behavioural patterns and percentage of activity, observed during arousal phases, showed no significant variations from one arousal to another whatever the duration of the arousals may be. Constant ambient conditions allowed us to show a free-running circadian activity rhythm, the period of which varied from 25 to 34 hours, depending on the individuals. Marmots seemed able to adjust their activity in relation to duration of their arousals. Adjustment of activity and adoption of postures reducing heat losses might contribute to a minimization of energetic expenses.