Caves have a variety of definitions. From the explorer’s point of view, they are openings in the Earth large enough for human exploration. From the biologist’s point of view, they are openings that will accommodate cave-adapted organisms. From a hydrologist’s point of view, caves are fragments of the conduits that transmit water through karst aquifers. Caves form by a variety of independent processes including tectonic movements of the bedrock, differential erosion, and bedrock dissolution by several different processes. Caves also form by the draining of flowing lava and by the melting and draining of glacial ice.