EXTERNAL AND INTERNAL BODY TEMPERATURE OF THE COMMON ADDER
Background . “Cold-blooded” reptiles are thermophilic and actively regulate body temperature raising it, when it possible. For many species of reptiles and for the common viper Vipera berus (Linnaeus, 1758), the temperature of different parts of the body, including external and rectal temperatures, is known to differ. However, in the literature there is no data continuously record the temperature of the integuments and viscera. Such observations are likely to reveal thermoregulation parameters. Materials and methods . The observations were carried out during May 2017 over an adult female adder, who lived in an aviary in an artificial shelter (Karelia). Microloggers were implanted under the skin of the back and into the abdominal cavity, fixing the body temperature every 2 minutes. All movements of the viper were recorded on video. Results . Observations have shown that at night and in the absence of the sun in cloudy weather, the temperature of the different layers of the body is the same. When heated under the rays of the sun, the temperature of the covers is on average 2 °C higher than the temperature of the viscera (up to 6,8 °C). With rapid cooling in the shade of clouds, the temperature of the covers may drop by 4 °C below the temperature of the viscera. The typical cooling behavior is a more compact arrangement of the rings of the body. The decoding of the video and logger readings revealed 45 such cases during cooling. Conclusions . The average difference between the external and internal body temperature was 1,3 °C, which coincided with early observations when using a remote thermometer. This makes it possible to consider the indicated difference of 1,3 °C as a thermoregulation parameter that causes adaptive behavior - a change of posture to reduce heat losses.