Photo by E. “Tex” Helm.
From “Carlsbad Caverns in Color,” National Geographic, October, 1953.
Bats by the Millions Take Four Hours to Clear the Caverns’ Mouths
Pioneer ranchers’ attention was directed to the cave by evening’s bat flights, which darkened the sky like the funnel of a tornado. By night the bats fly for insects; by day they sleep in a dark chamber.