Iguanas

Iguanas are believed to be monophyletic, that is, they have evolved from a single ancestral type dating back to the extinction of the dinosaurs. Except for the banded iguana of the Fijian islands, all species are found exclusively in the Western Hemisphere. Marine iguanas are the only living lizard which spends time in the ocean, exclusively existing on algae gathered from rocks either by diving or foraging on tidally exposed reefs. Only the banded iguana and the green iguana of South America are found in wet tropics, while all other species inhabit dry environments.

Iguanas are strictly herbivorous—with the exception of the spiny-tailed iguana whose young eat insects and a few species which occasionally eat readily available meat. Iguanas are selective about their diet, preferring easily digested fruit, flower buds, and tender young leaves.