Meet the Marine Iguana
The marine iguana is a one-of-a-kind species, the only lizard on Earth that swims and feeds in the ocean. With its dragon-like appearance, sharp claws, and flattened tail designed for swimming, it seems like a creature from another time. Unlike its land-dwelling relatives, the marine iguana has evolved the ability to hold its breath and dive for algae, spending up to 30 minutes underwater. Despite its fierce look, this species is gentle and slow-moving, often seen basking in the sun after a cold ocean dive.
Habitat
Marine iguanas are endemic to the Galápagos Islands and are found along rocky shores, intertidal zones, and mangrove forests. These reptiles rely on volcanic rocks to warm themselves after feeding in the chilly waters of the Pacific. Though they are excellent swimmers, they are never far from land, needing the sun’s heat to maintain their body temperature.
Lifespan
Marine iguanas can live between 5 and 12 years, and sometimes up to 60 years, with larger individuals typically having longer lifespans. Their survival is influenced by food availability and environmental conditions, particularly extreme weather events like El Niño, which can disrupt their food sources.
Diet
Their diet consists primarily of marine algae, making them the only herbivorous lizard that feeds exclusively in the ocean. Males dive deeper for algae, while smaller females and juveniles graze on algae growing near the shore. Due to limited food sources, marine iguanas have the remarkable ability to shrink their bones and organs during food shortages, reducing their size until conditions improve.
Reproduction
Breeding occurs once a year, with males establishing territories and engaging in head-bobbing displays to attract females. After mating, females lay one to four eggs in sandy nests, where they incubate for about three to four months. Once hatched, the tiny iguanas must avoid predators and make their way to the rocky shore to begin their unique marine lifestyle.
Interesting Facts
- Marine iguanas expel excess salt by sneezing it out through specialized glands in their nostrils.
- They change color during the breeding season, with males turning red, green, or turquoise to attract mates.
- These lizards hold their breath for up to 30 minutes while feeding underwater.
- Charles Darwin described them as “hideous-looking creatures, stupid and sluggish” – but they are a marvel of evolution!
Predators & Natural Threats
While adults have few natural predators, hatchlings and juveniles are vulnerable to hawks, snakes, herons, and crabs. Introduced species like feral cats, rats, and dogs also prey on eggs and young iguanas. Climate change, rising sea temperatures, and El Niño events threaten their food supply by reducing algae growth.
Behavior
Marine iguanas are highly social, often seen piled together for warmth. They regulate their body temperature by basking in the sun, darkening their skin to absorb heat and lightening it once they have warmed up. When swimming, they use their long, flattened tails to propel themselves through the water, much like an alligator.
Human Interactions
Though marine iguanas have no fear of humans, their populations are vulnerable to habitat destruction, pollution, and introduced predators. Tourists often observe them up close, but disturbances can stress them, particularly during nesting seasons.
Conservation Efforts
The Galápagos National Park and Marine Reserve protect marine iguanas from habitat destruction and human interference. Conservationists monitor populations, remove invasive species, and regulate tourism to minimize impact. However, climate change remains a growing threat to their survival.
Scientific Classification
- Kingdom: Animalia
- Phylum: Chordata
- Class: Reptilia
- Order: Squamata
- Family: Iguanidae
- Genus: Amblyrhynchus
- Species: A. cristatus
