Hibernation of the black-capped marmot Marmota camtschatica with body temperatures of 0 and −1°C

Abstract

The blackcapped marmot ( Marmota camtschatica Pallas, 1811) is the largest (in size and weight) repre� sentative of hibernating true squirrels. It is met in the mountain systems of Eastern Siberia from the Bar� guzin Ridge to the mouth of the Lena River and Chukotka Highland. The blackcapped marmots in Yakutian mountains live up to 1500 m above the sea level; in Transbaikalia, up to 1900 m; and in Kam� chatka, up to 1400 m. The depth of their burrows in Yakutia does not exceed 120 cm, and the temperature at the level of their hibernation chambers does not ele� vate above 2°C even in the summer season (3). The lowest temperatures in the inhabited part of the globe have been recorded in the Verkhoyan'e mountain sys� tem. In particular, the absolute temperature minimum near the city of Verkhoyansk is -67.8°C; characteristic of the soil conditions in the blackcapped marmot habitats is the presence of permafrost with a thickness of up to 500 m and a seasonally thawing horizon, typ� ically, of 60-100 cm (6). This marmot overwinters and hibernates at low positive and negative ambient tem� peratures over almost the entire period. The ecology of the blackcapped marmot in Yakutia has been rela� tively comprehensively studied (4, 7-9); several papers detail its hibernation, body temperature, and meta� bolic level (2, 5, 12). As for the experiment, the body temperature of three individual blackcapped mar� mots was monitored during their active period and in hibernation at ambient temperatures of -8 to -10°C. Three 1�yearold blackcapped marmots (