Hypogean fauna refers to the diverse range of organisms that live underground, particularly in caves and other subterranean environments. These creatures have adapted to life in complete darkness, often developing unique physical traits such as reduced eyesight and heightened senses of touch and smell. Common examples include various species of cave-dwelling fish, insects, and amphibians. These organisms play crucial roles in their ecosystems, contributing to nutrient cycling and serving as food sources for other animals. The study of hypogean fauna helps scientists understand evolutionary processes and the impact of environmental changes on biodiversity. Conservation efforts are essential to protect these fragile habitats from threats like pollution and habitat destruction.