Postprandial thermophily of Chinese green tree vipers, Trimeresurus s. stejnegeri: Interfering factors on snake temperature selection in a thigmothermal gradient

1. Measuring snake temperature selection in a linear thigmothermal gradient is a common way to determine preferred temperature (T_p). However, few investigators have checked the degree of instrumental interferences. We conducted three experiments to study the possible effect of thermocouples, the influence of seclusion, and the presence of water on the temperature-selecting behavior of Trimeresurus s. stejnegeri. 2. Thermocouples might change a snake's T_p by causing it to lift its prehensile tail from the gradient floor or affecting its movement. 3. With the videotape-recording method, T. s. stejnegeri presented postprandial thermophily only when seclusion sites and water were provided in the gradient. 4. In the absence of seclusion sites and water, the fasting and postprandial T_b was 23.0±1.2°C and 24.7±1.2°C, respectively. With seclusion sites and water, the fasting and postprandial T_b was 22.5±1.0°C (Tset=20.3-24.3°C) and 27.8±0.6°C (Tset=26.5-28.8°C), respectively.