Anchihaline caves are caves, usually coastal, containing a mixture of freshwater and saline water (usually seawater). They occur in many parts of the world, and often contain highly specialised and endemic faunas. Lechuguilla Cave, New Mexico A cave is a natural underground void large enough for a human to enter. ... Annual mean sea surface temperature for the World Ocean. ... In biology and ecology endemic means exclusively native to a place or biota, in contrast to cosmopolitan or introduced. ...