Reptiles and amphibians are distantly related to each other but in spite of some similarities, they can be distinguished by their physical appearance and different stages of life. Amphibians live "double lives" — one in water with gills and the other on land by growing lungs as they age. They are vertebrates and cold blooded (ectothermic). Early amphibians, a crucial link from fish to terrestrial reptiles, were the first animals to leave the sea and venture onto the land. Reptiles (meaning "to creep stealthily under cover of darkness") are a group of animals that have scales (or modified scales), breathe air, and usually lay eggs. Most reptiles live on land and reproduce by laying eggs. Crocodiles, snakes, lizards, and turtles are all examples of reptiles.