Methods for estimating the parameters of thermoregulation in reptiles (by the example of the common viper, Vipera berus L.)

We present the analysis of long-term studies of the thermobiology of the common viper, including the use of loggers, mini-sensors for recording the body temperature of a living individual. A series of traditional and original indicators characterizing the ability of the common viper to regulate its body temperature is considered. It is shown that the so-called thermoecological indicators characterize to a greater extent the conditions of stay of animals, but not their ability to thermoregulation. The thermophysiological indicators include parameters with both good and unsatisfactory statistical properties (in terms of variability and stability). The most stable indicator is that characterizing the physiological abilities of an individual or a group of individuals - "maximum typical temperature", assessed by the regression-quantile method. The maximum typical temperature is interpreted as the upper tolerance threshold, i.e. the true specific maximum body temperature. The main parameter of the viper thermoregulation is the maximum voluntary temperature, which is fixed at the moment when the animals avoids overheating. Recording the maximum voluntary temperature requires continuous monitoring of both the body temperature and the behavior of the reptile, which makes the calculation of the maximum voluntary temperature quite difficult and time-consuming. The simplest indicator for assessing the main parameter of thermoregulation (maximum voluntary temperature) was the median active temperature for the sample above 30 °C (close to the temperature of "full activity"). To compare different groups of animals, it is strongly discouraged to use statistical indicators assessing the range of variability of normal daytime temperatures or their averaging.