Planet Earth - Discovery HD

Caves (1x10)

Udgivelsesdato: Apr 22, 2007

This installment explores "Planet Earth's final frontier": caves. At a depth of 400 metres (1,300 ft), Mexico's Cave of Swallows is Earth's deepest Pit Cave freefall drop, allowing entry by BASE jumpers. Its volume could contain New York City's Empire State Building. In this episode divers explore the otherworldly cenotes of the Yucatán Peninsula, appearing to be flying in water (because it is so clear), allowing viewers a glimpse of the hundreds of kilometers of caves which have already been mapped. Also featured is Borneo's Deer Cave and Gomantong Cave. Inhabitants of the former include three million wrinkle-lipped free-tailed bat, which have deposited guano on to an enormous mound. In Gomantong Cave, guano is many metres high and is blanketed with hundreds of thousands of cockroaches and other invertebrates. Also depicted are eyeless, subterranean creatures, such as the Texas blind salamander and (bizarrely) a species of crab. Carlsbad Caverns National Park is featured with its calcite formations. Mexico's Cueva de Villa Luz is also featured, with its flowing stream of sulphuric acid and snottite formations made of living bacteria. A fish species, the shortfin molly, has adapted to this habitat. The programme ends in New Mexico's Lechuguilla Cave (discovered in 1986) where sulphuric acid has produced unusually ornate, gypsum crystal formations.