Hot rocks and much-too-hot rocks: seasonal patterns of retreat-site selection by a nocturnal ectotherm

(1) 1 studied seasonal patterns of diurnal retreat-site selection by a nocturnal, rock-dwelling lizard Christinus marmoratus. as well as the way physical characteristics of potential retreat-sites affect the thermal conditions within them. (2) Lizards were selective of the diameter and degree of shading of rocky retreat-sites, and these two variables significantly influenced the thermal conditions beneath rocks. Rock thickness also exerted a strong influence on thermal conditions but lizards were not strongly selective of this characteristic. (3) Seasonal changes in the pattern of retreat-site selection. and in thermal conditions within retreat-sites. strongly suggest that temperature affected quantitative changes in the types of rocky retreat-sites used by the lizards. A significant seasonal shift in the qualitative nature of retreat-sites used by lizards. from rocks during spring to deep crevices in the bedrock during summer, also appears to be thermally driven. (C) 2002 Elsevier Science Ltd. All rights reserved.