PBS
Pbs Nova: The Mysterious Life of Caves
Companion to a PBS program in the Nova series. There are wonderful photos of the Lechuguilla cave system in New Mexico, and some new information on how caves are formed.
Other
Missouri Conservationist Online: Missouri Cave Life
Excellent article describing a trip inside a cave. The article discusses the cave habitat and changes that occur as you go deeper into the cave. Includes interesting photographs.
Scholastic
Scholastic: Online Theme Unit for Caves
Discover more about caves through this online interactive theme unit. This resource provides links to sea caves, cave animals, caves in the United States, the science of caves and more.