Frio Bat Cave: Concan, Texas, U.S.A.

Quick—To the Bat Cave!

As the sun sinks quietly in the west Texas sky, there’s electricity in the air. Something is about to happen—something big (this is Texas, after all). The crowd gathers, waiting, watching. At first, there’s nothing. Then a flutter. And another. And in an instant, millions and millions of bats are pouring out of the cave entrance, like an immense pillar of dark smoke, in one of the most thrilling spectacles in the animal kingdom. The noise and the flurry of this mass movement of mammals are an amazing sight that holds people in awe year after year.

The Frio bat cave is located about 80 miles (129km) west of San Antonio, deep in the heart of the Texas Hill Country. The cave is tucked away on a private ranch, but it’s open to the public by taking an inexpensive scheduled tour. The tours operate on a weather-permitting schedule; call ahead for details. There are several other caves in the area that also host millions of bats, but they’re closed to the public.

This nightly ritual, when the Mexican free-tail bats come out to feed, involves so many bats that they show up on weather radar as rain clouds. And like rain clouds, they’re a welcome sight to Texas farmers—the bats eat roughly 2 million pounds of insects each night, including those that destroy local crops.

While waiting for the bats to emerge, you’ll be treated to a tale of the cave’s history. From the Civil War through World War I, it was mined for bat guano, which was used to make gunpowder; the guano drying kilns are still standing near the cave’s entrance. A much stranger part of military history comes from World War II, when bats from the cave were trapped to take part in top-secret Project X-Ray; it was believed that thousands of bats carrying small incendiary devices could be released over Japan, setting off thousands of fires—the plan was scuttled in favor of the atomic bomb, and the bats returned to civilian life. —ML

Tour: Hill Country Adventures ( 830/966-2320;

When to Go: Apr–Nov.

San Antonio (83 miles/134km).

$$ Neal’s Lodges, Concan ( 830/232-6118; $$ River Haven Cabins, Ranch Rd. 1120, Leakey ( 866/232-5400;

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