The energy metabolism of three species of snake (Coluber gemonensis, Coronella austriaca and Elnphe longissima) was investigated by polarography and direct calorimetry at 25 degrees C. The snakes produced a mean specific heat of 0.61 mW g(-1), a maximum of 0.94 mW g(-1) during locomotory activities and a minimum of 0.45 mW g(-1) during periods of rest. From simultaneous measurements of heat dissipation and oxygen consumption, calorimetric to respirometric ratios of 457, 637 and 309 kJ (mol O-2)(-1) for the three conditions were calculated.