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 exist ence 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 t ree, minimizing the risk of predation. Site selection is related to a preda tor-safe refuge and a suitable basking perch. We suggest that lizards attem pt to retain the winter refuge site for the neat breeding season, which has important implications for their life history. (C) 2001 Academic Press.