Every summer night, tourists line up at the mouth of a mysterious cave in Texas.
As the sun begins to set, a sound vaguely reminiscent of a rain storm begins to echo out of the cave, much to the excitement of the gathered crowd. The bats are coming. Ten million of them.
Located just outside of San Antonio in Comal County, Texas, The Bracken Bat Cave is home to the largest bat colony in the entire world. Every summer, around 20 million Mexican free-tailed bats migrate to Texas from Mexico to raise their young. The largest group of these winged creatures takes up residence in the Bracken Bat Cave.
For four hours every night through the months of March to October, the bats stream from the cave in spectacular fashion, blotting out the setting sun as they disperse into the night to feed. So many bats fill the sky that the squeaking mass of critters actually shows up on Doppler radar, prompting local meteorologists to excuse the area above the Bracken Bat Cave from their weather estimations.
The summer migration isn't just good for the farmers who rely on the bats to control pests that can potentially ruin crops, it's also good for the local Great Horned Owl population, who feed on the bats. Even raccoons and rattlesnakes will wait to snag a low-flying bat for a midnight meal.
The bat cave is located on private land owned by Bat Conservation International, and while access to the cave is restricted in order to protect the habitat of the bats, the BCI hosts four public viewing nights a month where bat lovers and tourists can watch in awe as the creatures make their nightly exodus.
If you want to witness the incredible site for yourself, make sure you reserve your spot well ahead of time, as slots fill up quickly.