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Earth Notes: The Mystery of the Mummified Bats

A small brown bat hangs upside-down among white crystals on a cave ceiling. It's dead but looks alive.
Shawn Thomas
A mummified myotid bat at its last perch among the gypsum crystals in Double Bopper Cave.

This is Earth Notes…

The Grand Canyon is riddled with caves, and many of them hold secrets…. But none so strange as the Mystery of the Mummified Bats.

Years ago, cavers got a permit from the National Park Service to explore and map a cave in the canyon. They were astonished to find hundreds, maybe thousands, of mummified bats. Some still clung to the walls or ceiling, so perfectly preserved in Arizona’s dry climate they looked ready to fly away.

Why were they there? Did they get snuffed out all together in one catastrophic event? To answer that question, scientists needed to use carbon dating to put precise ages to the mummies.

But the bats remained in a desk drawer at Northern Arizona University for nearly a decade before wildlife biologist Carol Chambers got funding for the project. The first dozen bats she tested surprised her: they were more than thirty thousand years old. In follow up studies Chambers learned the ages of the dead bats ranged from the present day to older than carbon dating techniques can measure. No catastrophe had befallen the animals. They had lived and died in those caves for generations.

It’s a stunning (and spooky) example of how caves in the Grand Canyon act as safe harbors for bats and other animals, allowing them to thrive for millennia despite drastic changes in climate. And this treasure-trove of mummified bats—the largest in the world—is now a top priority for scientific research. One mystery might be solved, but there are plenty more secrets yet to be discovered.

This Earth Note was produced by KNAU and the Sustainable Communities Program at Northern Arizona University.

Melissa joined KNAU's team in 2015 to report on science, health, and the environment. Her work has appeared nationally on NPR and been featured on Science Friday. She grew up in Tucson, Arizona, where she fell in love with the ecology and geology of the Sonoran desert.
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