Microhabitat Selection in Diet and Trophic Ecology of a Spiny-Tailed Iguana Ctenosaura hemilopha

Annual variation in the diet of adult spiny-tailed iguanas was studied by analyzing feces collected at 38 known iguana refuges in the desert of the southern Baja California peninsula. Iguanas consumed mostly plants, a small percentage of arthropods, their own skin, and remains from conspecifics. They consumed at least 22 of 83 plant species known to be present in the area. Leaves of three perennial Leguminosae species formed the year-round basis of their diet. Iguanas ate flowers and fruit when available. We propose that iguanas could be efficient seed dispersers for Cactaceae, but that they crush many of the seeds of leafy tree species. No significant differences in food consumption pattern were found between dry and rainy seasons. Iguanas apparently moved to neighboring trees only when searching for food. We propose that predation risk could have more influence than the nutritional value of plants on the species' foraging behavior and microhabitat selection in this area.