While present day marine reptiles do not exhibit great species diversity, they are comprised of an interesting mixture of different animals, including sea snakes, marine iguanas, sea turtles, and the marine caiman and saltwater crocodile. Undoubtedly, the most diverse of the group of marine reptiles are the sea snakes, with over 50 species. In addition, they are the only marine reptiles that spend their entire lives in the sea, even giving birth to live young there. All other marine reptiles require land to complete their life history. Sea turtles come ashore on beaches to lay their eggs, the marine iguanas of the Galapagos Islands bask in the sun for long hours on the rocks of the shoreline, and the marine caiman, like its freshwater counterpart, the alligator, spends much of its time lounging on the banks catching sun rays.
Certainly, the most well-known of the marine reptiles are the sea turtles. These, like marine mammals, are considered to be charismatic megafauna, having elicited great emotional outporings from the public, associated with their incidental deaths in shrimp trawls. Most of the sea turtle species are currently protected by the Endangered Species Act, having reached low to critical populations levels, mostly due to interactions with humans.