The iguanas get their babies from both types of nests. The disadvantages are that, if the number of reptiles increases more than the owners have space in their homes, it will be a big problem to feed them. It is difficult to manage and control when they already exist in a huge number and will not survive unless they get full care, proper food and shelter. These are mysterious animals and are kept as pets. So many stores sell young iguanas at low prices for keeping pets. Many people get attracted by these cute creatures and get involved with them to keep them as pets. It is a fact that these tiny animals can turn very large very soon and may also become aggressive. They essentially feed on marine algae that are almost imposible to create commercially. Genus Conolophus, have closest resemblance with the marine iguana. This iguana is also known as Galapagos Land Iguana and basically eats plants and cactus. The next varieties, Genus Ctenosauria are spiny tailed iguanas. Vitamins and minerals: Iguana requires a lot of Vitamin D3, calcium and phosphorous for growth of its bones and body. You should select the food containing these minerals and maintain the ratio of these elements 2:1. Feed them those foods, which have these nutrients. 4. Lighting; Proper lighting is most important for iguanas. You can get the details of the nutritious food advice for iguanas from those selling the pets. Many people like to feed their iguana with crush and lettuce, but they are not aware that it is just like sponge and does not have any nutrition value. The problem can further deteriorate with inadequate supply of calcium and vitamin D3 in food. In cold days they almost become immobile and easily fall prey to the marauders. They can move only slowly and they strike the invaders with their tails and bite the predators. When their breeding season comes, the male will mate with females and guard them against other males. Marine iguanas maintain their number and sizes according to the availability of food.