Bracken Cave

Coordinates: 29°41′14″N 98°21′09″W / 29.68715°N 98.352606°W / 29.68715; -98.352606

Bracken Cave is the summer home to the largest colony of bats in the world. An estimated 20 million Mexican Free-tailed Bats roost in the cave from March to October making it the largest known concentration of mammals. The cave is located in southern Comal County, Texas, outside the city of San Antonio. The 100-foot-wide crescent shaped opening to the cave lies at the bottom of a sinkhole, formed when the roof of the cave collapsed.

The cave and 1,521 undeveloped acres around it are owned by Austin, Texas-based Bat Conservation International, which restores the land to support native vegetation and an abundant variety of wildlife. Bat Conservation International bought the initial 697 acres from the Marbach family, and has been assisted in preservation efforts by The Nature Conservancy. Access to the cave is restricted to protect the habitat of the resident bats. Bat Conservation International offers evening guided tours to the cave to watch the bats emerge from the...