Marine Iguana

• fisiologíaIt is the only lizard that feeds in the sea, diving to graze algae, and sneezes the excess salt out through nasal glands.
• fisiologíaDuring the food shortages brought on by El Niño it can temporarily shrink its own skeleton by as much as 20%, reabsorbing bone tissue, and grow back once the algae return.
• It is the only lizard in the world that feeds in the sea. Of some 7,850 lizard species, only this one dives to eat algae.
• It shrinks to survive. During El Niño episodes the algae disappear and adults reduce their body length by up to 20%, bone length included, growing back when the food returns. It is one of the most extraordinary fasting responses documented in a vertebrate.
• And it does not just shrink: one study measured that during El Niño its relative mass falls by 17%, its girth by 12% and its resting metabolism by 20%. In other words, it actively shuts down its energy consumption.
• Those episodes can kill more than half of an island's population.
• It expels excess salt by sneezing it out: nasal glands concentrate the salt from seawater and expel it in a jet, leaving white crusts on its head.
• It must reach between 35 and 38 °C basking on the lava before it can dive, hence the carpets of motionless iguanas at dawn.
• Darwin saw it in 1835 on Fernandina and called it an 'imp of darkness'.
• Its total area of occupancy is estimated at less than 500 km², spread across ten island subpopulations.

Skeleton type

Vertebrate - internal bony skeleton (reptile)

Habitat & environment

Rocky lava shores of the Galápagos Islands; it basks in the sun on the basalt and dives to feed on algae, to depths of more than 30 m in large adults

Sources consulted: https://es.wikipedia.org/wiki/Amblyrhynchus_cristatus