Selection of diurnal retreat sites by the nocturnal gekkonid lizard Oedura Lesueurii

Velvet geckos (Oedura lesueurii) are small nocturnal lizards that use crevices under slabs of rock as diurnal retreat sites. In laboratory trials offering a choice of alternative crevice types, captive geckos showed consistent preferences based on characteristics such as the size of the overlying rock and the width, shape, temperature, humidity, and height above the substrate of the crevice itself. The presence and sex of conspecifics also influenced the selection of retreat sites. No preferences were evident with respect to crevice orientation (horizontal versus vertical) or type of substrate (rock versus soil versus sand) in our laboratory trials, but the distributions of geckos in the field suggest that the lizards prefer rocky crevices as diurnal retreat sites. Our study shows that velvet geckos evaluate a wide variety of structural, microclimatic, and social aspects of potential shelters, and bence can use complex criteria to assess the suitability of potential retreat sites.