More Research! The iguanas spend most of their time basking on boulders on rugged shorelines, but enter the water for feeding. They have flattened tails for swimming, strong claws to hang on to rocks while feeding, and tricuspid teeth to scrape algae off the surface of underwater rocks. The smaller iguanas, juveniles and females, feed in shallower water while the larger males dive down to feed. All iguanas show a strong preference for red and green algae and avoid brown algae if the other varieties are present. Since the water in the Galápagos is usually much colder than most tropical water (about 18-23 °C), the ectothermic ("cold blooded") iguanas can only feed for a limited time before they have to crawl out onto the black rocks to warm up in the sun. The iguanas' natural predator, the Galápagos hawk, can only capture small hatchling iguanas, but predation risk can be high in islands with feral introduced dogs and cats. I Hypothesis 1: If there is less then marine iguanas will die. Hypothesis 2: If there are fewer basking rocks, Hypothesis 3: If there are more then marine iguanas will die. Hypothesis 4: dogs and cats, then marine iguanas will die.​