Reptiles are a class of cold-blooded vertebrates that include animals such as snakes, lizards, turtles, and crocodiles. They typically have scaly skin, which helps prevent water loss, and most lay eggs with leathery shells. Reptiles are found in a variety of habitats, including deserts, forests, and wetlands. Reptiles are ectothermic, meaning they rely on external sources of heat to regulate their body temperature. They play important roles in ecosystems as predators and prey, helping to maintain the balance of their environments. Some reptiles, like tortoises, can live for many decades, while others, like geckos, have shorter lifespans.