Reptiles are a category of animals that includes snakes, lizards, turtles, crocodiles, and alligators. They are characterized by their scaly skin, cold-blooded metabolism, and reproduction that typically involves laying eggs. Reptiles are found in a variety of habitats, including deserts, forests, and wetlands, and they play essential roles in their ecosystems as predators and prey. This group of animals has a long evolutionary history, with some species dating back over 300 million years, showcasing their adaptability and resilience in diverse environments.