In 2000, Hotspots of Subterranean Biodiversity in Caves and Wells was published. It listed only 20 sites on the entire earth where 20 plus species of subterranean animals occur. At the time, three were in the United States (one cave in Kentucky, one in Alabama, and a deep artesian well in Texas). As a result of biologists surveying animals in Binkley Cave since 1997, Binkley Cave has now been added to this list of hotspots.
Due to the vast extent of the cave, its 38+ miles of passages host a wide variety of living spaces or habitats for these animals. For example, water habitats in Binkley vary from deep cave rivers where countless cavefish live to shallow pools of water created by dripping formations where tiny crustaceans live.
Another factor is geographic location. The Binkley system is located in an area that was adjacent to the great glaciers of the Pleistocene Ice Age. This led to a diverse fauna, some species are only known to exist in the Binkley cave system. Others are known only from caves within the drainage of our local Blue River, while some (like the eyeless cave crayfish) are found in caves from parts of Indiana and Kentucky.
So far 21 species of troglobites have been identified in Binkley Cave system and the biological survey continues. One example of a troglobite is the eyeless cavefish.
David C. Culver & Boris SketHotspots of Subterranean Biodiversity in Caves and Wells
Tours leave frequently throughout the day. You must arrive no later than 4pm EDT on weekdays and 4:30 on Saturday and Sunday to be guaranteed a spot on the last tour of the day. The cave temperature is 56 degrees all year. Weather is never a problem.
Closed only on Thanksgiving and Christmas Day.