Galápagos Marine Iguana

The marine iguana (Amblyrhynchus cristatus), also known as the sea iguana, saltwater iguana, or Galápagos marine iguana, is a species of iguana found only on the Galápagos Islands (Ecuador).

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.

Marine iguanas mostly eat seaweed and algae. Larger iguanas will dive into the sea in order to forage, sometimes diving as deep as 12 m and staying submerged for more than an hour. Under normal circumstances, they make shallow dives, usually lasting around 10 minutes. The smaller iguanas keep out of the water, feeding instead on algae on rocks in the tidal area.

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 onshore or underwater in heavy currents.

Before feeding the marine iguana must raise its body temperatures to approximately 36°C. These iguanas are ectotherms and can lose up to 10°C when in the ocean. To regulate their body temperature they must bask in the sun for long periods of time. Their black skin helps them to absorb lots of heat from the sun so they can dive into the cold ocean. And they even have special glands that clean their blood of extra salt, which they ingest while feeding.

They mainly live in colonies on rocky shores where they bask after visiting the relatively cold water or intertidal zone but can also be seen in marshes, mangroves, and beaches. Large males defend territories for a short period, but smaller males have other breeding strategies. After mating, the female digs a nest hole in the soil where she lays her eggs, leaving them to hatch on their own a few months later.

Their population is not well known. They are under constant pressure from non-native predators like the Galapagos hawk, the Galapagos racer snake, Lava heron, great blue heron, striated heron, short-eared owl, and frigate bird. They are protected throughout the archipelago and are considered vulnerable to extinction.

#Wildlife #RockyShores #Reptile