Unexplored South Dakota cave could tell millennia-old tale of climate change

Scientist calls Persistence Cave 'a warehouse of information' and says he expects to find 100,000 animal bones over the summer as team excavates entrance

The National Park Service is beginning to excavate the mouth of an unexplored cave in the Black Hills of South Dakota, and researchers believe it could help broaden our understanding of how the region's climate has changed over thousands of years.

A park service worker found Persistence Cave in 2004 on the grounds of Wind Cave national park, in western South Dakota, but the agency kept it quiet, partly to prevent amateur spelunkers from trying to explore the well-preserved site.