Marine iguanas of the Galápagos Islands are a wonder of evolvution

Marine iguanas are fascinating animals that exist in only one place on earth; the Galápagos Islands. They are descended from regular iguanas but they have changed over time so that they can thrive in this beautiful, but hostile environment.Show more

During the dry season there is little vegetation growing in this harsh climate. Food is scarce and competition for what little nourishment there is can be tremendous.

Marine iguanas evolved to be able to live on algae, but the catch is that the algae grows only underwater. The iguanas learned to feed when the tide receded, but competition drove them to seek out algae that grew outside of the intertidal zones. Marine iguanas have developed an ability to hold their breath for up to 30 minutes, allowing them to swim out beyond the surf and into a world full of food. They are able to dive as deep as 30m (100 feet) in search of food. Because the waters around the Galapagos Islands are cold, the iguanas must store up body heat by basking in the sun each morning before venturing out to feed.

Eventually, cold will drive them back onto land where they will stretch out on lava rocks to warm up again. Females and juvenile iguanas are not strong enough to withstand the crashing waves and strong currents as they seek algae. They feed closer to shore in calmer waters and leave the deeper algae to the larger males. Marine iguanas have also evolved to have long, powerful claws so that they can anchor themselves in the surge. Their mouths have shortened and become more suited for chewing on the plant growth that exists on the rock surfaces underwater. These iguanas, and the other animals of the Galapagos Islands helped Charles Darwin form his theory of evolution that changed the way we thing about our planet, as well as our own origins.