The term "hypogean" refers to environments or organisms that exist below the surface of the earth, particularly in caves or subterranean habitats. These areas are often characterized by unique ecosystems that have adapted to low light, high humidity, and limited food sources. Hypogean organisms, such as certain species of bats and cave-dwelling fish, have evolved specialized traits to survive in these conditions. Hypogean environments are important for scientific research, as they provide insights into biodiversity and evolutionary processes. Studying these ecosystems can help scientists understand how life adapts to extreme conditions and the role of subterranean habitats in the broader ecological landscape.