To regulate their body temperature they must bask in the sun for long periods of time. This acquired heat is important to the iguana because to obtain food the iguana must go into the water. The waters off the Galapagos Islands is controlled by the Humboldt Current. The Humboldt Current is a cold water current and causes the iguanas to lose heat rapidly. Habitat Marine iguanas live in colonies where shallow reefs occur with an extensive intertidal zone and a rocky coastline approximately 2 to 5 meters above sea level on the Galapagos Islands.
Softer substrate is needed for egg laying.
They sleep either exposed on the coastline or even up in mangrove trees. Young iguanas are found among the adults in most basking aggregations. Unlike adults, they spend a great amount of time in cracks and crevices. They are never far away from a hiding place. This endemic species has sparked a great deal of academic conversation about its' origin.