Reptiles, a diverse group of air-respiratory vertebrates, are characterized by their scaly skin, amniotic eggs, and ectothermic (chilly-blooded) metabolism. They can be typically classified into 4 living orders: Crocodilia (crocodiles and western hagnose, alligators), Sphenodontia (tuataras), Squamata (lizards and snakes), and Testudines (turtles a