The saltwater crocodiles, or Crocodylus porosus, are the largest reptiles that are normally referred to as "salties." They are indigenous to Northern Australia, Southeast Asia, and some regions of India but can also be found in some of the US wildlife parks and zoos. These top predators are very important in regulating fish and mammal populations, which balances the estuarine ecosystem and mangrove ecosystem.
This is because they are living fossils that are over 200 million years old. Their evolution is a show of unbelievable adaptability to survive in the thermal environment, to the sea environment, and be adapted to saltwater conditions, so that they can exist in rivers, estuaries, and coastal lagoons.