Seasonal Variations in Energy Turnover and Body Temperature in Free-Living Edible Dormice, Glis glis

Abstract

Edible dormice (Glis glis) face low food availability after emergence from hibernation, and during years when there is no seed production from their main feeding trees. In this field study we aimed to investigate seasonal changes of energy turnover and body temperature (T b) in edible dormice during periods of high and low food availability, to understand energy saving strategies, besides the use of hibernation and torpor. We therefore measured daily energy expenditure of nine adults using the doubly labelled water and resting metabolic rate of 20 euthermic individuals with portable gas analysers. Additionally, we analysed T b patterns of 118 individuals during years of high and low food availability. All measurements were carried out in the field during the active months of edible dormice between 1996 and 2006 in south western Germany. Results of this study demonstrate that energy turnover and T b in edible dormice vary markedly over their active season and among years. Variations of food intake and the heat increment of feeding are likely to cause a substantial part of these variations together with the reactivation of organs that are atrophied during hibernation. T b patterns strongly suggest that edible dormice reduce their T b to save energy during periods of limited food supply.