The much-maligned marine iguanas of the Galápagos Islands are so famously homely, even Charles Darwin piled on, describing them as "hideous-looking" and "most disgusting, clumsy lizards."

It's true, they're not pretty, with their wide-set eyes, smashed-in faces, spiky dorsal scales, and knotty, salt-encrusted heads. But what these unusual creatures lack in looks they make up for with their amazing and unique ecological adaptations.

Population

Scientists figure that land-dwelling iguanas from South America must have drifted out to sea millions of years ago on logs or other debris, eventually landing on the Galápagos. From that species emerged marine iguanas, which spread to nearly all the islands of the archipelago. Each island hosts marine iguanas of unique size, shape and color.

Aquatic Adaptations

They look fierce, but are actually gentle herbivores, surviving exclusively on underwater algae and seaweed. Their short, blunt snouts and small, razor-sharp teeth help them scrape the algae off rocks, and their laterally flattened tails let them move crocodile-like through the water. Their claws are long and sharp for clinging to rocks on shore or underwater in heavy currents. They have dark gray coloring to better absorb sunlight after their forays into the frigid Galápagos waters. And they even have special glands that clean their blood of extra salt, which they ingest while feeding.

Threats to Survival