Caving is also physically grueling. During a typical trip to two caves, Lewis and his assistant had to scramble through a narrow passage while gripping rocks jutting out from each side, wade on hands and knees through freezing water and slog through "boot sticking" mud.
"My definition of a good cave trip is when you can stop the bleeding at the end of the day," Lewis said cheerily as he prepared to enter. Walking into the dark, the biologist started whistling "We're Off to See the Wizard," pausing to exclaim, "Get ready for the lions and tigers and bears!"
Shining his small head lamp on the traps that had lured small animals over two weeks, Lewis began inventorying the cave's inhabitants. His first haul included a spider, a primitive insect-like creature called a springtail that can catapult itself into the air to avoid predators, and an unpigmented millipede, which he examined while scanning the walls for live specimens.
One trap offered up a rare find, a tiny blind cave beetle called pseudanophthalmus. The water held another trove of creatures, including a blind white crayfish that was probably several decades old and a sand-colored sculpin fish with black spots that seemed to disappear into the muddy waters.
Some of the species of beetles were so small they looked like dots. Lewis said he would be able to distinguish them only under a microscope. "You have to think small when you do this," he said.
Once Lewis issues his final report next year, Garland said, the Conservancy will decide which caves might be worth buying to shield them from development. In the mid-1980s, the Conservancy paid $29,000 to buy Hubbard's Cave and the 50-acre forest that buffers it in McMinnville, Tenn., home to more than 100,000 federally endangered gray bats.
"It's important to identify the caves that support a rare species before something happens to them," said Robert Currie, an Asheville, N.C.-based U.S. Fish and Wildlife biologist. "Knowing where something is is a first requirement before you can protect it."
While state officials could take some steps to guard the caves, their task is complicated by the fact that invertebrates such as the millipedes are not considered wildlife under state law and do not enjoy as many protections.
Some Tennessee animals such as the Indiana bat are on the brink of extinction, but Garland said she is optimistic that conservation advocates would be able to protect many plants and species.
"We still have so much in this state," she said. "We haven't lost everything yet."
