The iguanas flourishing in Fernandina become brick red and dull green. The sizes of marine iguanas also vary from one island to another. In Isabella and Fernandina, you can get the biggest marine iguanas of complete Galapagos Islands. There are smallest marine iguanas living in Genovesa. Marine iguanas are classified as poikilothermic creatures. Female iguanas do not have heavy fat pockets on head and their jaws are smaller. Moreover, their femoral pores are also smaller. Male iguanas erect their spine at back while in courtship and bobble the head. They are more aggressive while in courtship. At the same time they are timid also and will run away out of fear. Therefore, you have to feed them with suitable food in proper manner. Scientifically, Iguanas are categorized as herbivores; as such they should not be fed with green leaves as their primary diet. It is recommended to feed them with worms and other fleshy food rich in animal protein. Maybe, you have watched iguanas on TV eating some insects. As the iguana grows, you should be able to make changes in the size of its cage rather than shifting it from one cage to another. It is advisable to go for a bigger cage from the beginning. That will provide more freedom to iguana for moving around. Food: Now coming to the food to be given to your pet iguana, naturally it should be given a healthy food. Heat tape, under tank heaters and ceramic lights are some of the other alternatives. The Food: The food given to iguana should be healthy and nutritious. You can follow a diet plan for them in consultation with an expert. The iguanas normally eat plants, vegetables and fruits. They should not be fed food containing animal protein. There is another species related to Rhinoceros Iguana found in Navassa and that is almost on the verge of extinction. The scientific name for Rhinoceros Iguana is cyclura comuta. Here are some critical characteristics about this species. Physical characteristics of Rhinoceros Iguana: This is a very strong type of lizard.