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Villa Luz: Mexico’s Poisonous Cave

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By John L. Eliot Photographs by Stephen Alvarez

An underworld of hydrogen sulfide harbors life-forms awesome and awful.

Get a taste of what awaits you in print from this compelling excerpt.

We could smell the cave long before we saw it. Along the mile-and-a-half (2.4-kilometer) trail from the Almandro River a natural paradise unfolded. Oropendolas, hummingbirds, motmots, and other tropical birds perched in ceiba and quebracho trees. Leafcutter ants paraded across our path in this lush rain forest in southern Mexico’s Tabasco state. But as the rotten-egg stench increased, paradise was about to be lost. At the entrance of the cave my scientific companions—all accomplished cavers—and I donned respirators for protection against the vapors within.

Then we descended. Louise Hose, a geologist at California’s Chapman University, led me to a rock wall festooned with long white mucus-like colonies of sulfur-eating bacteria.

“We joke that this cave has a cold, and we call these ‘snottites,’” Hose said. The bacteria oxidize sulfur compounds in subterranean springs that feed into the cave—sulfur is the basis for nearly all its life. Besides the incredibly acidic snottites, the researchers term other forms of bacterial slime “phlegm balls.” Some forms of bacteria are new to science, and some are even beautiful, like those christened “biovermiculations” by Hose. On some walls they grow in an intricate lavender texture, like a rich tapestry.

Get the whole story in the pages of National Geographic magazine.

This job can kill you! Photographer Stephen Alvarez talks about working in this lung-scorching, acid-filled cave.

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We offer this forum board in Spanish and English.

Not every National Geographic assignment is an exotic adventure. What trips have you taken that took a turn for the worse? Tell us your stories.

Presentamos este forum en inglés y en español. ¿No todas las misiones de National Geographic son aventuras exóticas. ¿Qué viajes han hecho que se volvieron pesadillas? Comparta su historias.

In More to Explore the National Geographic magazine team shares some of its best sources and other information. Special thanks to the Research Division.

How many times have you swatted a fly and chuckled in hindsight because you couldn’t believe it didn’t move fast enough to avoid the big colored piece of plastic headed right for its tiny body? Well, some flies are slow, but to be a midge (a tiny fly) in Cueva de Villa Luz, you can’t be slow. If you are, life will pass you by before you know it. Adult midges found within this cave are thought to live for only five to ten days. These midges are nonfeeding, all the same size, and their sole purpose is reproduction. With a life span of less than two weeks, there’s certainly no opportunity for hesitation.

—P. Davida Kales

Showcaves of the World
This site is available in both English and German and provides general information on caves around the world. Features include a list of countries, maps, a bookstore, links, and humor.

Cueva de Villa Luz, Tabasco
A website featuring scientists’ exchange of information about Villa Luz. Slides, video, articles, and news releases are among the materials available.

Plattsburgh State University of New York
A summary of Dr. Kathy Lavoie’s trip with two of her students to Villa Luz. The article provides general information about the biology of the cave.


Hose, Louise D. “Cave of the Sulfur Eaters,” Natural History (April 1999), 54-61.

Peterson, Roger Tory, and Edward L. Chalif. A Field Guide to Mexican Birds. Houghton Mifflin Company, 1973.


Aulenbach, Nancy Holler, Hazel A. Barton, and Marfé Ferguson Delano. Exploring Caves: Journeys into the Earth. National Geographic Books, 2001.

Miller, Thomas. “Inside Chiquibul: Exploring Central America’s Longest Cave,” National Geographic (April 2000), 54-63.

Stone, William C. “Cave Quest: Trial and Tragedy a Mile Beneath Mexico,” National Geographic (September 1995), 78-93.

Brownell, M. Barbara. “Come on Down to the World Underground,” National Geographic World (September 1994), 24-28.

Mysteries Underground. National Geographic Videos, 1992.

Siffre, Michel. “Six Months Alone in a Cave,” National Geographic (March 1975), 426-435.

Stirling, Matthew W. “On the Trail of La Venta Man,” National Geographic (February 1947), 137-172.


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