Marine iguanas are some of the Galapagos’ most resilient residents. By adapting to their harsh environment over millions of years, these remarkable reptiles have set themselves apart from any other lizard on the planet. With aquatic adaptations that see them foraging in the ocean and distinctive salty sneezes, this scaly species is testament to the power of evolution. Eager to learn more? Read on for a deep dive into our favourite facts about marine iguanas.
- Aquatic adaptation
- Salty sneezes
- Multi-coloured mating season
- Shrinking skeletons
- Interspecies interactions
Aquatic adaptations
Thanks to their arrival on the Galapagos Islands and divergence from land-dwelling iguanas some five to ten million years ago, marine iguanas boast some fascinating aquatic adaptations. Firstly, their stubby snouts (with razor-sharp teeth) help them lead a healthy herbivore lifestyle by scraping algae off rocks. While feeding, despite being unable to breathe underwater, these swimming sensations can hold their breath for up to 40 minutes and dive as deep as 98ft. This blows most reptiles out of the water, as marine iguanas are the world’s only sea-feeding lizard.
Salty sneezes
Our next fact about marine iguanas proves that living the sweet seaside lifestyle presents some not-so-pretty problems. While feeding, marine iguanas ingest a fatally high salt level, and so have developed glands that remove salt without removing water. The result? Salty sneezes that, lacking the ability to use tissues, form crusty crowns on their head. Despite wearing them with pride, they might be the reason why Charles Darwin labelled marine iguanas as ‘hideous-looking creatures.’ It turns out that beauty really is in the eye of the beholder.
Multi-coloured mating season
Despite normally sporting black scales to help absorb heat after an icy ocean dip, mating season is a different story for marine iguanas. From December to March, adult males flaunt different colours depending on their species: on Española Island, the aptly nicknamed ‘Christmas iguana’ flushes bright red and green; on Santa Cruz they develop patches of red; and on Fernandina they wear dull green and brick red. These dazzling displays are all in a bid to impress the females, however, it’s often their combination of size, strength and territory defence that eventually wins them over.
Shrinking skeletons
A surprising fact about marine iguanas is that bigger isn’t always better. Due to their dependency on the sea for food, they’re susceptible to changes caused by the El Niño-Southern Oscillation, an irregular climate cycle that affects temperatures worldwide. This can cause their food supplies to dwindle dramatically, putting larger iguanas at more risk. The seemingly impossible solution? To shrink their skeletons up to 20% shorter. This bizarre strategy actually works, with smaller iguanas faring better in tough times than their larger counterparts.
Interspecies interaction
Mockingbirds and marine iguanas prove to be the most unlikely of friends. Researchers have discovered that these large lizards are the only non-vocal animals known to recognise and utilise another species’ calls. By eavesdropping on mockingbirds, they respond to the birds' warning calls about nearby Galapagos hawks (who enjoy snacking on both species). What’s more, mockingbirds are known to peck at marine iguanas to remove ticks, providing both a snack and a parasite extraction service. Delicious.
Written by Evie Buller.
