Wildlife & Habitat

Bats in cave

Although the refuge is only 199 acres in size, a diversity of species make their home here. Two hundred species of birds, mammals, fish, reptiles, and amphibians use the refuge.

  • Wildlife

    Here at Fern Cave National Wildlife Refuge, there is a unique array of residents living in the cave, in addition to the endangered bats. One survey expedition by a biologist and geologist documented cave fish (Typhlichthys subterraneous), bluegill (Lepomis machrochirus), yellow bullhead catfish (Ictalurus natalis), cave salamanders (Eurycea lucifuga), northern slimy salamanders (Plethodon glutinosus), honey-colored crickets (Othoptera: Euhadonecus), mosquitoes (Diptera: Clulicidae), crane flies (Tipulidae), heliomyzid flies (Diptera: Heliomyzidae), frogs (Anura), and white millipedes (Diplopoda).  

    Above ground, white-tailed deer, turkeys, migratory songbirds, squirrels, opossums, raccoons, and rabbits abound. 

  • Gray Bats

    Wildlife Viewing

    Fern Cave contains the largest wintering colony of gray bats in the United States, with over one million bats hibernating there in the winter. The gray bat weighs 8-11 grams and has a 27-32 cm (11-13 inches) wingspan. The average life span is 14-15 years. For this species, mating occurs in September and October; pups are born in late May or early June and are capable of flight within 20-25 days. Remarkably, 95 percent of these bats only hibernate in eight caves. 

  • Indiana Bat

    Indiana bats 150x118

    The Indiana bat (Myotis sodalis) is primarily a winter resident of Sauta Cave. The Indiana bat is 6 to 9 grams and has a 24 to 28 centimeter (9 to 11 inches) wingspan. This bat also averages a 14 year lifespan. Mating occurs in mid-August and early September. Once babies are born in June, they are raised under loose bark, primarily in a wooded streamside habitat. Nearly 85 percent only hibernate in nine locations.

  • American hart's-tongue

    American harts tongue fern

    The American hart's-tongue fern is a federally threatened species. Identifying, protecting, and restoring endangered and threatened species is the primary objective of the U.S. Fish and Wildlife Service's endangered species program. This fern is found in close association with outcrops of dolomitic limestone, in coulees, gorges, and in cool limestone sinkholes in mature hardwood forests. It requires high humidity and deep shade provided by mature forest canopies or overhanging rock cliffs. American hart's-tongue fern prefers soils high in magnesium.