Photo of the Day 27 October 2007

Bats in Cueva de Villa Luz, Mexico, 2001
Photograph by Stephen Alvarez
Bats emerge from the inky depths of Cueva de Villa Luz in southern Mexico. Hydrogen sulfide, which is poisonous to humans, permeates the cave's walls, streams, and air, sustaining a rich variety of bizarre organisms. In addition to bats, spiders, mites, amblypygids, and small, hemoglobin-rich fish thrive in the sulfur-saturated environment.