Indiana Jones would not want to explore this cave, where snakes hang from the ceiling, waiting to snag bats from the air for dinner.
Near the town of Kantemó in southern Mexico’s Yucatan Peninsula, the cave is a growing destination for adventurous ecotourists. About 300 visitors enter the cave a year, hoping to get a glimpse of the unusual behavior, says Liliana Garcia Ramirez, the director of Amigos de Sian Ka’an, a local nonprofit.
The yellow-red rat snakes (Pseudelaphe flavirufa) are not venomous, Ramirez says, and, as fierce as they look, they aren't a threat to people.
Typically, the relatively small serpentsy prey on rodents, lizards, and other small animals on the ground, in forests. But over time, some have discovered a new niche: bats. (See six bat myths busted, in time for Halloween.)
Six species of bats are known to frequent the cave, giving the snakes a varied spread. When the bats swarm in or out of the cave en masse, the snakes slide down from their crevice homes. Dangling down, they pluck the tasty morsels right out of the air with their mouths.
The adaption is rare but not unheard of—another cave in Puerto Rico is reported to be home to Puerto Rican boas (Epicrates inornatus) that are known to pluck bats out of the air.
In the Yucatan, locals—many of whom are of Maya descent—have long known about the snakes, referring to their lair as “Bat Cave.” It is also sometimes called the Cave of the Hanging Snakes (or serpents).
“Local people are committed to preserving this cave,” says Ramirez, adding that many view it as a unique part of their heritage. “They also know that it helps bring tourists into the area.”
All visitors must be accompanied by a guide, all of whom are certified, Ramirez says. No one is allowed to disturb or touch the animals, and only groups up to ten are allowed, to minimize impact. The snakes don’t seem to be bothered by spectators, she says. (Learn how snakes lost their legs.)
Part of the cave is flooded and is home to blind albino crustaceans. The surrounding forest and nearby lagoon is home to 60 species of birds, crocodiles, and fish.