Evolved long ago from a terrestrial iguana, one of the stangest creatures to populate the rugged shores of these remote islands is the only sea-going lizard in the world: the marine iguana (Amblyrynchus cristatus). Charles Darwin, during his five-week visit here in 1835, coined the name "imps of darkness" for this strange-looking animal, often described as hideous by early visitors, and giving the islands an unwelcoming aspect, as an area fit only for ante-diluvian monsters such as giant tortoises and strange lizards! The nineteenth century naturalist was the first to discover, as he dissected their stomach contents, that the iguana's diet consisted entirely of marine algae, and not fish as was previously thought. He also tortured the poor creatures by picking them up and repeatedly throwing them into the sea, to study their reaction (which was invariably to swim back to shore).

This amazing animal had to evolve in several ways to become adapted to the marine environment, the most important of which was the development of an extremely effective salt gland. Once out of the water, they form "tangles" of iguanas on the shorelines, and sneeze repeatedly to get the rid of their excess salt (a process made possible by the formation of a salt gland behind the animal's eyes), which often gives the group of animals a grayish appearance as the salt dries. To make up for the body temperatures that lower drastically as the animal dives, marine iguanas are black, and lie together in large groups, which enables them to warm up again as quickly as possible. They have long fingers and nails to cling onto the rocks amidst the wave action of the intertidal area, though no webbed fingers, as they use their long, vertically-flattened tails for locomotion in the water, as is pictured at left. Their generic name, Amblyrynchus, refers to their blunt faces, allowing them to get closer to the rocks for grazing. We had several opportunities of seeing these weird and wonderful animals in action this week, as we were lucky to have low tide during several outings, including the beautiful late afternoon stroll in Puerto Egas, Santiago Island.