Marine Iguana

Overview

The Marine Iguana (Amblyrhynchus cristatus) is a unique reptile endemic to the Galápagos Islands and is the only lizard in the world that routinely forages in the sea. These specialized animals have adapted to a marine lifestyle, spending significant time in cold coastal waters to graze on algae before returning to land to bask and regulate their body temperature.

Appearance

Marine iguanas are typically grey to black, a coloration that helps them absorb heat from the sun after foraging in chilly ocean waters. They possess a spiky dorsal crest, short blunt snouts, and long, sharp, recurved claws that allow them to grip rocks securely. Their tails are laterally compressed, which aids in efficient swimming. Juveniles are often distinguished by a lighter-colored stripe running along their back.

Biology & Behavior

As ectotherms, these iguanas must balance their time between the cold ocean and the warm sun to maintain an optimal body temperature. They are frequently observed basking in large colonies on rocky shores. To manage the high salt intake from their marine diet, they possess specialized nasal glands that allow them to expel excess salt, often appearing as if they are "sneezing."

Feeding

Marine iguanas are herbivores that feed almost exclusively on marine algae. Foraging strategies vary by size: larger males are capable of diving to greater depths to graze, while smaller individuals and females typically feed in the intertidal zone during low tide.

Reproduction

During the breeding season, males establish and defend territories. Females dig burrows in sand or volcanic ash, often hundreds of meters inland, to lay their eggs. After laying, the female guards the nest for a short period before leaving the eggs to incubate on their own.