Fig. 3. Relationship for V. rosenbergi of (A) the rate of oxygen consumption (_O2) and (B) heart rate (fH) versus body temperature (T_b±0.4°C) during heating and cooling in fasting (squares) and postprandial (circles) lizards. Irrespective of digestive state, a hysteresis in _O2 during heating and cooling was not observed, although, both during heating and cooling between 25°C and 35°C, _O2 was significantly higher in postprandial lizards than in fasting lizards. There was a significant hysteresis in fH during heating and cooling from 19°C to 35°C in fasting animals although, for postprandial animals, the fH hysteresis was significant only between 24°C and 35°C. Values are means ± S.E.M. (C) The absolute differences in fH between heating and cooling for fasting (grey bars) and postprandial (black bars) animals.