In the darkness, a pallid bat hears the sound of crawling legs. The bat swoops in to face dangerous prey. The scorpion does not yield easily, and stings repeatedly, even after being snatched in the bat's jaws. Unaffected by the stings, the bat enjoys a hearty meal. It remains mysterious how this small mammal can be immune to the scorpion's potent venom. Pallid bats inhabit much of the western United States, including Carlsbad Caverns National Park.