By M. Keith Hudson, Wildlife Biologist

When many people think of the natural beauty of Alabama the mind’s eye imagines beautiful verdant forests, rivers and lakes teeming with wildlife, or perhaps a favorite white-sanded beach. However, Alabama has another tremendous natural resource -- the world underground -- its caves and karst systems. Karst refers to a landscape pockmarked with sinkholes, caves, and underground streams.

Alabama has one of the highest densities of caves and karst features found anywhere in the world and the northern part of the state has a particularly high number. Much of north Alabama is underlain with deep deposits of limestone, formed over millions of years by the deposition of innumerable calcareous organisms in a shallow marine sea. These gray limestone deposits can be seen along highways that cut through the area’s mountains and hills. Most of the caves in Alabama were formed as water percolated through this limestone and dissolved away materials and formed openings and tunnels in the limestone. When enough material has been dissolved away, a cave is formed.

This geology underlies much of south-central Tennessee, north Alabama and northwest Georgia, or the TAG region as cavers refer to it. It is no accident that the national headquarters of the National Speleological Society (NSS) is in Huntsville, within the TAG area. The NSS is an organization dedicated to the purpose of advancing the study, conservation, exploration, and knowledge of caves. The NSS is the umbrella organization for local or regional caving groups, or “grottos,” which explore caves through recreational caving, sometimes called spelunking. An organization affiliated with the NSS is the Alabama Cave Survey (ACS), a group that surveys and maps Alabama caves. According to the ACS, there are over 4,100 known caves in Alabama and the ACS has mapped about a quarter of those. In most years, several dozen more are reported to the group. The NSS also contains groups who specialize in cave rescue and cave conservation.

Because a cave usually has constant environmental conditions and relatively permanent physical conditions, several unique animals inhabit and have adapted to dwell in caves, including several species of fish, insects, salamanders, and of course, some types of bats. Because caves are a unique and limited habitat, most of these creatures are rare and a few are considered endangered species. Alabama caves are habitat to two species of endangered bats, the Gray and Indiana bat. One cave in LauderdaleCounty contains the endangered Alabama cavefish that is found nowhere else in the world but this one cave. The Alabama cavefish is arguably one of the, if not the, rarest of all vertebrate species.

Several other Alabama wildlife “species of concern” use caves, including Rafinesque’s big-eared bat, the Southeastern myotis bat, the little brown bat, the Tennessee cave salamander, the Southern cavefish, the Alabama cavefish, and the Allegheny woodrat. Many types of wildlife will use the “twilight zones” around cave entrances for shelter and for dens. Many birds, such as the cliff swallow and barn owl, regularly utilize cave openings in which to nest. In a recent status assessment of wildlife in Alabama, caves and cave systems ranked third of six terrestrial habitats in terms of importance to imperiled wildlife. Sauta, Key and Fern caves in north Alabama, are small national wildlife refuges established and managed for the benefit of their endangered bats and/or cavefish.

Alabama has a number of caves easily available to the public to visit. Some of these include the Alabama State Parks of Cathedral Caverns and Rickwood Caverns. Several private caves, such as Sequoyah and Desoto Caverns, are also available for commercial tours. These commercial caves highlight the cave environment and the beautiful cave formations found within. Indeed, when most folks imagine caves, they likely imagine stalactites, stalagmites and other unique cave formations. RussellCaveNational Monument is also an interesting place to visit and learn about paleoman’s use of caves, though access is restricted to the cave’s entrance. For the more adventurous, the NSS offers opportunities for exploring “wild” caves for the novice and advanced caver.

While exploring caves may not be everyone"s cup of tea, everyone should appreciate the recreational, aesthetic and ecological value of Alabama's wild underground.