The Marine Iguana (Amblyrhynchus cristatus)
Why are Marine Iguanas so amazing?
Marine iguanas are only found in Galapagos Islands and have several unique adaptations, most notably the ability – unique amongst lizards – to live and forage in the sea. They can dive over 9 meters (30 feet) into the water in search of food. This isn’t the only amazing adaptation. Research in recent years found they actually decrease in length by up to 20% (it is believed their bones actually shorten) in El Niño years when food is in short supply. When their food supply improves they return to their previous size.
How did they get to Galapagos?
Scientists think that millions of years ago land-dwelling iguanas from mainland South America must have drifted out to sea on logs or land rafts, eventually being carried across by ocean currents to the Galapagos. From that species emerged marine iguanas which spread to nearly every island in the Galapagos, with each island hosting its own unique population in terms of size and colouring.
Where is the best place to see them?
Marine iguanas have now spread across the entire archipelago and you spot them in most places, but the absolute best place to see them is Fernandina Island. Fernandina is the most pristine island in Galapagos and enjoys the benefits of the cold water upwelling from the Cromwell Current. This creates ideal conditions for algae and seaweed which the iguanas eat. The iguanas here are also amongst the largest in Galapagos (the smallest are on Genovesa). In addition to size variations between islands, the marine iguanas also vary in colour with the males on Espanola (and other southern islands) acquiring a dramatic red and teal colouring around breeding time.
When is the best time to see them?
The short answer is all year long! In terms of seasonal variation, the breeding cycle is activated by the start of the rainy season in January/February when the males get territorial and start to mate. Soon after this the females start to lay their eggs which are then ready to hatch with the arrival of the nutrient rich cold water currents from late April and May through to early June.
They look fierce… are they?
Although they look fairly fierce with their spiky dorsal scales and knotty salt-encrusted heads, they are in reality gentle herbivores, surviving exclusively on underwater seaweed and algae. Over the years explorers weren’t always complementary in describing their looks. Charles Darwin described them as “hideous-looking” and “most disgusting, clumsy lizards.” They make great subjects for photos: because they are cold blooded reptiles they spend the early morning and late afternoon trying to warm up so they don’t move much. This gives you the ample chance to compose the perfect shot!