Shelly's Guide to Cool Caves

By | September 1, 2015
From Xplor: September/October 2015

Hi, I’m Shelly. I study Missouri’s bats. Let’s go see what makes caves so cool. You’ll be surprised by all the different critters that live down here. So slap on your helmet, turn on your headlamp, and get ready to crawl, slip, and slide underground.

It took millions of years for these cave formations to grow, as water slowly trickled down through rock and left these minerals behind. Let’s check them out!

Stalactites Drip. Drop.

That slow but steady drip — over thousands of years — leaves behind enough minerals to form immense stalactites. They look like icicles, but they’re made of rock!

Cave Bacon

Water dripping off cave ceilings can leave behind a thin strip of cave bacon, made of calcium. It’s so thin that light shines through. Cave bacon always makes me hungry for breakfast!

Soda Straws

In some caves, these delicate soda straws hang from the ceiling. Dripping water forms tiny, hollow straws. Aren’t they beautiful?

Cave Pearls

Cave pearls are a rare treat. They can grow as big as marbles! They form when sand gets coated with calcite. A little water movement keeps them from sticking to the ground. Stalagmites Dripping water also forms stalagmites on the cave floor.

It takes about 100 years for them to grow a quarter inch. Remembering the difference between stalactites and stalagmites is easy — you might step on a stalagmite.

Bats love it down here!

It’s cool and damp year-round. Most bats spend their winters in caves and their summers in trees or barns, raising their young. Gray bats, however, live in caves all year and raise their babies (called pups) here.

So Many Bats

The big brown bat is one of the most common bats in Missouri. You’ve probably seen them swooping in for a meal near light poles. Missouri has many other types of bats, too, such as tricolored, little browns, and grays — 14 different kinds in all. Sometimes I find rare bats, like the silverhaired bat.

Insect Eaters

Bats are Missouri’s top insect eaters. The Show-Me State doesn’t have vampire bats or fruit bats, like other parts of the world. Sure Missouri’s bats eat mosquitoes, but they love bigger meals like beetles and moths, which give them more energy. Bats can eat their body weight in insects in a single night.

Sound off

When chasing down a meal, bats use their eyes and also rely on echolocation (ek-ohlo- cay-shun), a form of sonar. Bats emit high-pitched chirps up to 200 times per second. By listening to the echoes, they can locate and nab prey. It sounds way harder than playing Marco! Polo! in the swimming pool, doesn’t it?

Bunches of Bats

Those are hibernating gray bats. They can pile on top of each other four deep. I’ve seen 250 bats snuggled together in a space no bigger than this page! Sometimes clusters contain hundreds of thousands of bats. As a cave biologist, it’s my job to count them all to help other scientists learn whether bat numbers are going up or down. Watch this short video to see how we count bats:

Sleepy Time

When bats hibernate, their body temperatures drop to the cave temperature. Their heart rates slow down, too. Most bats wake up every few weeks to get a drink, but most don’t eat all winter long. Tricolored bats can hibernate for six months.

Missouri, the Cave State, has more than 7,000 caves. About 900 different types of animals have been seen down here. That’s a whole lot of life underground!

Life in the twilight zone

Most cave life is near the entrance, where there’s sunlight. This is called the twilight zone. It provides wildlife with food, water, and shelter. You might see eastern phoebes building nests or turkey vultures raising chicks. This is a great place to find snakes and other reptiles cooling down on hot summer days. Since the air is damp, mosses and ferns thrive.

Exploring the Dark Zone

It’s pitch black all the time back here. Whoa! Don’t climb that dirt pile — that’s a giant heap of bat droppings, called guano, from a gray bat colony. Guano is rich in nutrients and all sorts of cave insects live on it, such as cave crickets, millipedes, and pseudoscorpions.

Unique and Rare

Grotto Salamander

Cave critters are uniquely evolved for life underground. The grotto salamander is the only blind salamander in Missouri. They live in total darkness and prefer caves with a spring or stream running through them. See more photos and a video at

Tumbling Creek Cave Snail and Pink Planarian

The Tumbling Creek cave snail and the pink planarian, like many of Missouri’s cave creatures, are found nowhere else on Earth. The pink planarian is a flatworm, one of the simplest animals with a brain and nervous system. It sucks the juices out of tiny amphipods to stay alive. Learn more about pink planarians at

Ozark Cavefish

Ozark cavefish are very rare. Cavefish live most of their lives in total darkness, so they don’t develop eyes. Caves have a limited supply of nutrients, so cavefish depend on food brought in from outside, like leaves, sticks, and bat guano. Learn more about these fish at

Thanks for getting muddy with me! Remember, caves are fragile and loaded with unique animals. So always be respectful underground.

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This Issue's Staff

Brett Dufur
Les Fortenberry
Karen Hudson
Regina Knauer
Angie Daly Morfeld
Noppadol Paothong
Marci Porter
Mark Raithel
Laura Scheuler
Matt Seek
David Stonner
Nichole LeClair Terrill
Stephanie Thurber
Cliff White