Marine Iguana - photo by Agnes Gram
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Marine iguanas are found only in the Galapagos archipelago. It is believed that they and the land iguanas evolved from a common ancestor that somehow reached the isles. They are vegetarians and feed on marine algae in the intertidal zones. They feast on seaweed in shallow pools and on the rocks, but also dive underwater to feed. Such dives are usually only 5-15 m deep and last a few minutes, but there are records of dives lasting half an hour.

Marine iguanas discharge excess salt from their nostrils while basking in the sun to warm themselves after submerging. The salt is what gives this iguana the characteristic white head displayed in the photo.

Periodic declines of sea iguana populations, with high mortality rates, during El Niños result from a reduction in availability of the seaweed they subsist on. Climate change and shifts of the oceanic currents would jeopardize this species survival. Galapagos iguanas are also threatened by exotic species introduced to the islands – notably dogs and cats.

Marine Iguana – photo by Agnes Gram
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