TIME CONSTANTS OF HEATING AND COOLING IN THE EASTERN WATER DRAGON, PHYSIGNATHUS-LESUERUII AND SOME GENERALIZATIONS ABOUT HEATING AND COOLING IN REPTILES

1. 1.|In keeping with other reptiles, core temperature of the lizard Physignathus lesueurii responds more rapidly to a step function increase in temperature than to a corresponding decrease. 2. 2.|Observations on twelve species (five families) of non-Chelonian reptiles heating and cooling in air and water show that strongly predictable relationships exist between thermal time constants and body size. Chelonia show a different pattern. 3. 3.|These observations are compared with the predictions of a simple model which, although not sufficiently complex to simulate physiological changes, provides insight into the relative importance of the physical and biological factors which underlie the observed relationships. © 1979.