The term for a creature that lives both on land and in water is "amphibian." Amphibians are a class of animals that typically undergo a distinct life cycle, starting their lives in water as eggs or larvae (tadpoles) before transitioning to adult forms that can live on land. Common examples of amphibians include frogs, toads, and salamanders. They are characterized by their moist skin, which aids in respiration and hydration. Amphibians play crucial ecological roles, acting as both predators and prey in their ecosystems. They are also sensitive to environmental changes, making them important indicators of ecological health.