The effect of temperature on the rate of oxygen consumption and heart rate has been investigated in the Red Sea, inter-tidal wedge clam Donax faba. The 010 values for both oxygen consumption and heart rate were often < 2.5 and were relatively constant over a wide range of temperature. This suggests that wedge clam is well adapted for life in high temperature environment. It was noted, however, that behavioural mechanisms were important in reducing the degree of temperature stress that could be experienced in the field.