As the sun goes down over Stuart Bat Cave in southern Texas, half a million Mexican free-tailed bats spiral into the sky. For a few minutes, the pulsing, chirping cloud blots out the summer twilight in a display that’s either terrifying or inspiring. As a backpacker, you should be cheering. That’s because a single bat eats 1,000 insects a night. The colony leaving Stuart Bat Cave will consume 5 tons–the weight of a small bus–before dawn.
Bats comprise a diverse mammalian group found on every continent except Antarctica. They are the only mammals capable of flight, and despite their rodentlike appearance, they are more closely related to primates such as chimpanzees. Three-quarters of bat species eat insects like moths and beetles, while a few others feed on fruit, nectar, or small lizards. Only three Central and South American species drink blood from sleeping animals.
To the Bat Cave
Devil’s Den State Park, AR
The sandstone crevice caves dotting the Ozark highlands are home to big brown and red bats. In summer, hit the 1.5-mile Devil’s Den loop trail around dusk, so you reach the 550-foot-deep bat cave when the creatures emerge. And don’t miss Bat-O-Rama XVIII (June 8–10), with hikes and demos planned. (479) 761-3325; arkansasstateparks.com/devilsden
Kickapoo Cavern State Park, TX
Every night from mid-April to mid-September, more than half a million bats fly out of the Stuart Bat Cave in this undeveloped state park 130 miles west of San Antonio. Sign up for a biweekly guided hike to the cave entrance ($5), or explore the nearby hillsides on the park’s 14-mile trail network. (830) 563-2342; tpwd.state.tx.us
Pinnacles Nat. Monument, Ca
Located 60 miles southeast of San Jose, this Salinas Valley maze of canyons and spires is home to a nursery colony of Townsend’s big-eared bats. From the visitor center, hike the Bear Gulch Cave Trail through a network of talus caves, which formed when house-sized boulders fell into narrow canyons. (831) 389-4485; nps.gov/pinn