Modern reptiles include the alligators and crocodiles, turtles, lizards, and snakes. They all have several typical characteristics: They have a protective covering of scales or plates, they lay eggs, they are cold-blooded, they breathe with lungs instead of gills, and they have five clawed toes on each foot (with exceptions, of course, such as snakes; and alligators only have four toes on their back feet, but five on their front feet).