Winter refuge characteristics of Spiny-tailed iguanas, Ctenosaura hemilopha, in Baja California Sur, Mexico

Winter refuges of spiny-tailed iguanas were located in old woodpecker nests in giant columnar cacti (cardons) (50%), and in other tree cavities (50%). The most important factors determining the choice of cactus were the existence of other holes, and the cactus height. Because iguanas use the winter refuges also in summer, refuges may allow lizards to feed and bask on the tree, minimizing the risk of predation. Site selection is related to a predator-safe refuge and a suitable basking perch. We suggest that lizards attempt to retain the winter refuge site for the next breeding season, which has important implications for their life history.