Comparison of thermoregulation parameters of grass snake and common viper

The parameters of thermoregulation of two sympatric species of widespread snakes are considered: the common viper (Vipera berus L.) and the grass snake (Natrix natrix L.). The analysis of unique data obtained by continuous recording of reptile body temperature by loggers was carried out. The calculation of the parameters was made by the original author's methodology and included 6 indicators: maximum highest temperature, maximum typical temperature, median activity temperature, temperature during basking, sum of temperatures, minimum temperature. Four out of the six indicators in the viper were significantly higher than in the grass snake. The viper shows greater tolerance to low temperatures, but, at the same time, is a more thermophilic species than the grass snake. The inactive common viper effectively accumulates heat, while the constant spontaneous activity of the grass snake does not allow it to reach high body temperatures.