Bracken Cave is a cave located in southern Comal County, Texas, outside the city of San Antonio. The 100-foot (30 m)-wide crescent shaped opening to the cave lies at the bottom of a sinkhole, formed when the roof of the cave collapsed.

Mar 20, 2025 · Bracken Cave is the summer home of more than 15 million Mexican free-tailed bats (Tadarida brasiliensis), making it the world’s largest bat colony and one of the largest concentrations of mammals on earth. The emergence of these millions of bats, as they spiral out of the cave at dusk for their nightly insect hunt, is an unforgettable sight.

Bracken Cave, on the northern outskirts of San Antonio, is home to the world’s largest bat colony, with more than 15 million Mexican free-tailed bats. It is a key maternity site for this species, and females congregate there each year to give birth and rear their young.

Located less than 20 miles from downtown San Antonio, Texas, Bracken Cave Preserve is the largest bat colony in the world — home to over 20 million Mexican free-tailed bats (Tadarida brasiliensis).

In 1992, we purchased Bracken Cave and the surrounding 4.7 acres of land to protect the largest colony of bats in the world. Over 30 years later, through a series of additional land purchases, that small initial acreage has grown by more than 300% into our 1,458-acre Bracken Cave Preserve.

Located roughly 30 miles northeast of San Antonio lies Bracken Bat Cave—the world’s largest bat colony. Each year, millions of Mexican free-tailed bats can be found roosting here between March and October.

Sep 27, 2023 · If you can’t make it to Bracken Cave, keep your eyes peeled. Mexican free-tailed bats roost all over Texas in caves, highway overpasses and bridges, like Austin’s Congress Avenue bridge, where the city’s famous urban bat colony lives.

Near San Antonio, a 1,521-acre property houses the world’s largest bat colony. Welcome to Bracken Cave, where millions of Mexican free-tailed bats roost each year between March and October. Have you ever seen a million of anything? Probably not.

Nov 20, 2013 · An estimated twenty million tiny flying mammals take up residence in this cave between March and October, making it not only the largest such colony of bats, but perhaps the largest concentration...

Bracken Cave, Texas. Every evening in the summer, around 20 million Mexican free-tailed bats fly out from the Bracken Cave, thereby creating the densest concentration of mammals on Earth. When the bats come out, the sound of so many bats is like running water.