National Geographic : 2007 Sep
Massive, venom-spitting pincers make this pseudo scorpion a formidable predator that can grapple with feisty prey from a safe distance. A single cave yielded three species. "They're a cave's great white sharks," Joel Despain says. CHTHONIID,UNIDENTIFIEDSP.,0.14 IN, KAWEAHCAVE but the local troglobites could be far older. The Sierra have been uplifting and eroding for tens of millions of years, and mountains long gone may once have held caves; when they wore out, the occupants could just have moved downstairs. On the other end of the evolutionary timescale are endemic diplura and harvestmen in near freezing Panorama Cave, in the alpine zone at 10,600 feet. This area was glaciated only 10,000 years ago, and it is hard to believe anything sur vived under a mile of ice and meltwater. Like Dar win's finches, these creatures must have arrived and evolved not over eons, but in human time. Unfortunately, the futures of many troglo bites may be shorter than their pasts. Just 41 species are on federal endangered or threat ened lists, but the Nature Conservancy says 95 percent of the thousand species known in the United States are actually imperiled. Caves pro vide ready conduits for seeping pesticides and sewage from cities and farmlands; troglobites are exquisitely sensitive to such poisons. Entire aquifers such as the Edwards are fast being drained, and as the water disappears, so does aquatic habitat. Some caves are simply excavated out of existence for roads and buildings. The Kauai wolf spider, which inhabits lava tubes in Hawaii, is facing competition from a new invader: the brown recluse spider. In Sequoia Kings, officials worry about airborne fertilizers and pesticides from the heavily farmed adjoin ing San Joaquin Valley-not to mention scores of marijuana growers who have invaded the parks' backcountry and apply the same stuff. Even scientific expeditions, it must be admit ted, can be a hazard. More than once, team mem bers lightly brushed a tiny bug while turning over a rock, or crawling along: end of troglobite. 146 NATIONAL GEOGRAPHIC . SEPTEMBER 2007 In Crystal Cave, they peered respectfully at-but did not touch-a sink-size series of rimstone pools supplied with water dripping from the ceil ing. A few grayish, jellylike things the size of string snippets cruised the surface's underside-newly discovered aquatic flatworms known from this spot, and this spot only, on Earth. One must be careful: Hairs, dandruff, and lint shed by humans may provide food sources that nourish compet ing alien surface mites, fungi, and bacteria, which also hitchhike in on humans. Finally, climate change-the force that may have helped create many troglobites-could help destroy them. Most caves have cool, constant temperatures that reflect the yearly mean outside. The critters are finely tuned to this constancy. If temperatures keep ascending at their current rate, some troglo bites may not adjust rapidly enough. For now, the frontier is still there. In late August last year, four amateur cavers were poking around a cliff face in the Sierra. They found a softball-size blowhole, enlarged it, climbed in, and discovered one of the most spec tacular caves in the western U.S. Its cathedral like spaces are up to a hundred feet wide and richly decorated with sparkling crystals and for mations in every color of the rainbow. It has been named Ursa Minor, for the massive skeleton of a bear found lying at the foot of a curtain of stone. The first people to rappel in saw uniden tified reddish worms clinging to the wall next to them. Farther back, one man thought he saw a flicker of movement in a pile of rocks. O k A Tight Squeeze Writer Kevin Krajick and photographer David Liittschwager found their story in the dark, in passages too small to turn around in. Read more in On Assignment at ngm.com/0709.