The entrance zone is most like the surrounding surface area. Some shade-loving green plants grow in the twilight zone but extend only to the deepest point where light penetrates. Temperature in the variable temperature zone fluctuates with the weather outside the cave. Deeper into the cave, in the constant temperature zone , the temperature stays at 58 degrees regardless of weather on the surface.
Biologists recognize three kinds of cave animals. Those that live above ground but often retreat to caves - bats and crickets - are trogloxenes , "cave guests." One trogloxene in Blanchard Springs Caverns is the Indiana bat, an endangered species. Animals living mostly in the cave but with the ability to survive outside it - some salamanders, frogs, and harvest men (daddy longlegs) - are troglophiles , "cave lovers." Animals which spend their entire lives in the cave's total darkness and uniform environment are troglobite , "cave dwellers." Like the white Ozark blind salamander, many are sightless and without pigment. This four-inch-long salamander, native to Blanchard Springs Caverns, was the first cave dwelling amphibian found in America.
After the mosses and ferns of the entrance zone, little plant life - except for bacteria, mold, and fungi - occurs farther back in the cave. The reason is obvious. Some animals can return to the surface for the food and energy they need to exist, but plants growing in the cave must be able to find a source of energy already "packaged" - in the form of decaying wood, leaves, and other organic matter.
Bacteria in the debris washed into the caverns by floods and run-off sustain some form of life. Microscopic organisms are food for slightly larger aquatic cave animals - flatworms, isopods, and amphipods, few of them even an inch long. They are devoured by still larger animals, such as salamanders and crayfish, major performers in the cave food web.
Even with the washed-in debris, many cave animals could not survive without the trogloxenes that regularly return to the surface for food. Bat droppings, or guano, supplement bacteria, mold, and fungi as food sources for the smaller non-aquatic cave animals - millipedes, snails, beetles, and other insects - which, in turn, are eaten by salamanders, spiders, and crickets.