Subterranean fauna refers to the diverse range of animals that live underground, often in dark and moist environments. These creatures have adapted to life below the surface, developing unique features such as reduced eyesight, elongated bodies, and specialized sensory organs. Common examples include earthworms, moles, and blind cave fish. These animals play crucial roles in their ecosystems, such as aerating soil and decomposing organic matter. Subterranean fauna also contributes to nutrient cycling, which supports plant growth above ground. Understanding these organisms helps scientists learn more about biodiversity and the health of underground habitats.