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Abstract

Field and laboratory studies of thermal relations, metabolism and winter dormancy were conducted on the sand lizard, Acanthodactylus boskianus. During daily activity times the lizards were slightly, but significantly warmer than their environment. The standard metabolic rate was exponentially related to temperature. The maximum Q10 3.86 occurred between 25 and 30C and minimum one 1.56 between 35 and 40C. There was no evidence of dormancy or reduced metabolism due to reduced temperature to 15C in summer. Oxygen consumption was essentially the same in the field lizards and in captive ones held either in outdoor cages or at 15C in summer, when measured at 15C or 35C, but consumption was significantly higher in both groups than in field animals when measured at 25C. Lizards become dormant when exposed continuously to short photoperiods in winter. This lizard could not be maintained in an active condition through winter under laboratory conditions used successfully to keep other local lizards active. Despite the length of photoperiods used 8 hday or 16 hday, both groups showed a significantly reduced metabolic rate at 15C comparable to those measured at 25C or above. Therefore, dormancy and metabolic rate are controlled independently. The winter dormancy is controlled by reduced photoperiod, but lower metabolic rate is controlled by reduced temperature.