Wintering conditions for the adder, Vipera berus (Viperidae, Reptilia), in the southern of Karelia

In the southern part of Karelia, on the Kizhi island, the temperature dynamics in piles of stones (collected by peasants from fields), in which the common viper takes shelter from the winter cold, was studied. A key role in experiencing winter is played by snow drifts covering the stones from the outside, and heat coming from the depths of the earth. It has been shown that in ordinary winters, the temperature stays at 0°C for three months in the winter shelters of the viper, often drops down to -2°C, and even lower for a short time. Thaws turn out to be disastrous, reducing the snow cover depth before the return of frost.