Bats in Wonderland

Kartchner Caverns Designers Prove That Cave Lovers and Bats Can Go Happily Down the Same 'Rabbit Hole' Bats in Wonderland

On a warm fall day in 1974, two young men, Gary Tenen and Randy Tufts, fell down a rabbit hole on a path that would take them into a wonderland. Well, not a rabbit hole, really, though rabbits took shelter in it from time to time. They actually descended into a sinkhole that water had worn into the porous limestone of the Whetstone Mountains of southeastern Arizona.The two Tucsonans, along with other geologists and cavers, had been poking around in the foothills of the Whetstones for years, playing the geological odds they would find such an entrance into the earth. Tufts had even explored this sinkhole in 1967 before moving on to cave-rich country higher up in the mountains. Though others had come and poked into it in the meanwhile, the dark pit remained a mystery.

At the bottom of that 15-foot-deep hole, Tufts (who died in 2002) and Tenen felt something that they had not noticed before: a draft of moist air coming from somewhere within the earth. The cave was exchang-ing its air-literally breathing. Moreover, they could smell the acrid, loamy tang of bat guano, proof positive that a cave lay somewhere below.

ing its air-literally breathing. Moreover, they could smell the acrid, loamy tang of bat guano, proof positive that a cave lay somewhere below.

Tenen and Tufts had found the entrance to one of Arizona's most treasured natural wonders, Kartchner Caverns. A masterwork of geological forces in pristine condition, the extensive limestone cave was home to a small population of Myotis velifer, or cave myotis, a species of the widespread bat family called Vespertilionidae, whose Latin name hints at a bat's favorite time, twilight. Most of the world's vespertilionids are cave dwellers, though some members of the family's 355 species make their home in wells, mineshafts, tunnels, tree hollows and even buildings.

The myotis of Kartchner Caverns had hit the jackpot: they had found a cave undisturbed by humans, so far as anyone knew, since the dawn of time. Numerous spots along the ceiling of what would eventually be called the Big Room, a football-field-long jumble of stalactites, stalagmites, pools,shields and flowstone, were covered with the bats' oily footprints, and mounds of guano rich enough to sustain a thousand gardens lay on the cave floor. The only real hitch, from a bat's point of view, was a peril attendant in getting into and out of the cave. A wily tribe of ringtails (Bassariscus astutus), creatures nicknamed "miner's cats" though related to raccoons, had learned to wait at the tiny entrance that Tenen and Tufts found, there to snare a meal on the wing. The ringtails notwithstanding, Kartchner Caverns has long been a summer migratory home and nursery for a population of 1,000 to 2,000 Myotis velifer. The bats begin arriving there in midto late April from their Mexican wintering grounds. They alight on the rough surface of the cave ceiling, making use of cracks and fissures to stabilize themselves. Then they settle in, head down and wings folded. Pregnant females give birth in late June to a single "pup," or rarely, twins. The youngsters are wholly dependent on their mothers, clinging to them like increasingly heavy fruit. Several times a night, a mother will tuck her pup away in some sheltering niche on the ceiling and fly out of the Big Room to catch insects; on returning,

Ecology of Guano

Hanging Around While hanging upside down may not make much sense to upright-walking bipeds, it makes perfect sense to bats. The position is ideal for takeoff (bats become airborne by hang-gliding rather than launching like birds). Hanging comes naturally, thanks to an adaptation that makes bat talons, connected by tendons only to the upper body and not to muscles as in a human fist, clench tight when relaxed.

Circle of Life In the food chain, guano, or bat dung, keeps cave life going. Cave myotis bats produce copious amounts of guano, which is fine with the bacteria and fungi that feed on it, as well as the mites, lice and nematodes that sup on this product and the arachnids and insects that feast on those critters. Skeletal myotis remains and guano as old as 50,000 years have been found in the Throne and Rotunda rooms of Kartchner Caverns.

Fertile Ground Guano has long been prized as nature's best fertilizer. Nitrogen-rich bat guano feeds plants for vigorous, leafy growth. Growers of spinach, lettuce and herbs have taken advantage of the batty brew, as have farmers of tomatoes, peppers, cucumbers, cantaloupe and many other fruits and vegetables.

Batty Schemes Bats have long been admired and maligned, studied and avoided. From Batman paraphernalia to Web sites suggesting "bat guano for Mother's Day," the bats inspire the unlikely. In a peculiar plot, World War II-era American researchers "recruited" thousands of Southwestern bats, planning to attach small fire bombs to the mammals and send them to Japan, where they envisioned countless infernos when the bats went to roost.

she locates her youngster by its individual smell and the sound of its cry, as distinct as a human baby's voice. So it goes for a few weeks, until about early August, when the colony's young are capable of both flight and hunting. After training the young in both skills, the colony moves in early to mid-October as the Chihuahuan Desert nights begin to cool. Then mother and pup make their way down into Mexico. Just what the fathers do during the migration is a subject that scientists are now studying. A standard compendium of the bats of the world, though, puts it thus: "Males do not exhibit an active interest in the young." Other creatures besides the occasional ringtail owe their livelihoods to the bats. Some, such as certain snakes and owls, feed directly on the vespertilionids. Other creatures feed indirectly, dining on what the bats produce. The Kartchner Caverns myotis colony, by a couple of estimates, removes half a ton of insects from the skies around the cave, including plenty of mosquitoes, a bane to any summer evening. A half-ton of insects adds up to a substantial haul

Taking a Bite Out of the Biters

Bats, nature's bug patrol, play their role happily. Humans nursing itchy welts and fearing the mosquito-spread West Nile virus (in 2005, there were 3,000 verified cases of West Nile in the United States alone) can take heart. Seventy percent of the world's bat species and almost all U.S. bats, including myotis, feed mainly on mosquitoes and other insects.

Going Batty

More than a thousand female cave myotis bats bear and tend young among Kartchner's shield formations, spearlike stalactites and the larger grounddwelling stalagmites, massive columns, fried-egg formations and fragile draperies, birdsnest needle quartz and hollow soda straws. Throughout the summer, the colony consumes about half a ton of insects. DAVID ELMS JR.

while the bats are resident in the great limestone cave, and that in turn means a steady supply of guano. In a perfect example of the great biologist Charles Elton's "food chain," a variety of fungi and bacteria break the guano down and in the process become food for creepycrawlies such as nematodes, mites and lice, which in turn feed spiders, scorpions, centipedes and crickets, all found in a great abundance in the moist, warm cave. In fact, almost all of the 39 species that live in the cave depend on bat guano for their survival, directly or indirectly.

On finally entering the limestone cavern after widening the entrance (thereby making the ringtails' work more difficult), Tenen and Tufts knew at once that they, too, had hit the jackpot, the kind of discovery that cavers spend their lives seeking and rarely find. To protect their treasure, they swore other cavers to secrecy, then launched a sometimes-James Bondish campaign to enroll Kartchner Caverns as a state park and thus preserve its sensitive environment. The process took some 14 years, partly because the discoverers and the scientists insisted that the park safeguard the bat colony. The Greta Garbo of bats, Myotis velifer wants noth-ing more than to be left alone, as scientists discovered when early work on the park subjected the colony to all kinds of human-associated stimuli, ranging from the occasional clicks of an infrared camera to shuffling feet and the usual throat-clearing and muffled conversa-tions of a tour group. Each click and whisper alarmed the bats, raising the terrible possibility that in fleeing the disturbance, a mother might drop a newborn pup on the hard floor below.

Thanks to the Arizona State Parks' leadership, those shy bats and their young are safe. The park closes the Big Room during the bats' half-year residency, affording Myotis velifer a unique sanctuary-for no other park in any other state has given such extensive protection to a species that is not yet endangered, but vulnerable to disturbance. That the bats are generous enough to share their homes with us while they're away is a boon. It's fitting that we honor their privacy when they're at home, deep in Kartchner Caverns' wonderland. Al