Regulation of Body Temperature in the Blue-Tongued Lizard

Lizards ( Tiliqua scincoides ) regulated their internal body temperature by moving back and forth between 15° and 45°C environments to maintain colonic and brain temperatures between 30° and 37°C. A pair of thermodes were implanted across the preoptic region of the brain stem, and a reentrant tube for a thermocouple was implanted in the brain stem. Heating the brain stem to 41°C activated the exit response from the hot environment at a colonic temperature 1° to 2°C lower than normal, whereas cooling the brain stem to 25°C delayed the exit from the hot environment until the colonic temperature was 1° to 2°C higher than normal. The behavioral thermoregulatory responses of this ectotherm appear to be activated by a combination of hypothalamic and other body temperatures.