Metabolism of the Iguanid Lizard Uta Stansburiana in the Supercooled State

Abstract
The iguanid lizard U. stansburiana regularly enters the supercooled state at temperatures below the in vitro freezing point of its blood and other body''fluids (-0.60 [plus or minus] 0.04[degree] C). The survivorship LD50 [50% effective lethal dose] for minimum deep body temperature is -5.8[degree] C. Weight-specific O2 consumption is given for the body temperature range 5.0[degree] - -5.0[degree]C. Slight differences in minimum thermal tolerance and respiratory metabolism of samples collected during winter and summer months were not statistically significant at the 5% level. Relevant behavioral thermoregulation to this winter-active species is discussed.