Marine Iguana

Fascinating facts about the Marine Iguana

• The marine iguana is the world's only seafaring lizard — and it holds its breath like a champion freediver. Diving to depths of 12 metres in search of algae, these reptiles can stay underwater for up to an hour, their heart rate dropping by half to conserve oxygen. When they surface, they expel excess salt through specialised glands in their nostrils, producing a spray that gave them the nickname 'spitting dragon' among early explorers.
• A marine iguana's body temperature plummets 10°C when it dives into the cold Pacific waters of the Galápagos — so it basks on volcanic rocks for up to 3 hours afterwards to rewarm itself. This peculiar cycle means these reptiles spend more time sunbathing than feeding, a trade-off unique among modern lizards that reveals how marginal life is on a volcanic island with unpredictable food supplies.
• In 1982 and 1997, El Niño events killed up to 90% of the Galápagos marine iguana population by warming the ocean and killing their algae food source — yet they rebounded. Their ability to shrink their body length by up to 20% during food shortages, and their tolerance for near-starvation, suggests evolution has hardwired survival through climatic chaos into their bones.
• Charles Darwin famously called the marine iguana 'hideous-looking' and 'most disgusting, clumsy lizard' — yet he was watching an animal found nowhere else on Earth, one that had colonised the Galápagos from mainland South America roughly 4.5 million years ago. That single founding population, marooned on volcanic rock, became the template for everything we now know about how species adapt to extreme isolation.
• Male marine iguanas engage in head-butting contests that can last for hours, their skulls slamming together repeatedly as they compete for breeding territory on crowded rocky beaches. The largest males — weighing up to 1.3 kg — dominate the best feeding grounds and mating sites, making body size a countdown timer: grow large or lose everything to the next generation.

At a glance

About the Marine Iguana

As the waves crash against the sun-baked shores of the Galapagos, a most singular creature emerges from the turbulent surf, its scaly form glistening like polished onyx as it hauls itself onto the rocky outcroppings. The marine iguana, with its spiky crest and eyes that seem to hold a primordial wisdom, moves with a deliberate slowness, as if savoring the warmth that seeps from the black volcanic stone beneath its feet. In this desolate yet majestic landscape, it reigns supreme, a remarkable and resilient sentinel of the sea, its very existence a testament to the boundless adaptability of life on Earth.

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