The Ultimate Kids (and Parents) Guide to the International Year Caves & Karst: 7 Things to know about Kentucky’s Caves

We’re here to be your Kentucky experts during the International Year of Caves & Karst. And we know that your kids will have questions. Well, we have answers that will explain the terminology and landscape, and we have great experiences with caves, walking trails, hiking trails, paddling trails, horseback trails, and even a cool hands-on museum that we’re sure the whole family will enjoy. And did we mention kangaroos? Follow us into the exciting world of caves & karst! Make sure you click on the links that will take you to more cool information.

1. What are caves and how are they formed?

A cave is an area or space under the surface of the earth, in hillsides, or in cliff walls. Caves are usually a complicated system of connected underground passageways that are like an underground maze.

It takes a long, long time for a cave to form, because the natural processes that make a cave are very slow. Most caves are formed in rocks that can dissolve more easily like limestone, marble, dolomite, and gypsum. Solutional caves are the most common, and they are formed from rainfall and chemical processes.

Kentucky is home to Mammoth Cave National Park. There are more than 400 miles of cave passageways mapped, making it the world’s longest cave. They have a Junior Cave Scientist  Program with resources that are currently online to get you ready for your visit.

Entrance sign to Mammoth Cave National Park

2. Do all caves look alike?

Some of our caves have beautiful formations created over many years by water dripping from the surface through the ground. Stalactites look like icicles hanging down. They form from water dripping from the roof of the cave. Stalagmites grow upward, and this is usually from water that dripped off the end of stalactites. Sometimes stalactites and stalagmites join together in the middle, forming columns. You’ll find some of these on certain tours of Mammoth Cave and also on tours at Mammoth Onyx Cave.

Other caves, like Hidden River Cave, have passageways cut by rivers that flow through the cave. Hidden River Cave is located right in the middle of the small historic town of Horse CaveTours there take you across the world’s longest underground swinging bridge to Sunset Dome, the largest dome room in the entire area. You can also zip line across the mouth of the cave and rappel down the limestone face of the cave.

There are even caves in our own Green River. Blue holes are deep, circular columns of water that form when rainwater dissolves a sink hole through limestone rock. You can spot a blue hole easily because of the color. You can even take a canoe or kayak trip along our own Green River to look for karst formations, blue holes, and springs.

Mammoth Onyx Cave at Kentucky Down Under Adventure Zoo

Hidden River Cave (Photo by @bardomc)

3. What is karst?

The word “karst” means stony ground, and Kentucky is one of the most famous karst areas in the world. Our gently rolling landscape with “knobs” (small hills) and sinkholes has shallow soil with layers of limestone underneath.  This karst terrain has developed over thousands of years as the rock is slowly dissolved by weak acids found naturally in rain and water in the soil as the water moves underground.

You can see the rolling landscape as you drive along our roads, you can even see sinkholes, and you can see layers of limestone along our trailsYou’ll want to make sure to take a walk, hike, horseback ride, or paddle while you’re in our area to see if you can find some karst.

Sinkhole plain with karst formations

4. Are caves dangerous?

Exploring unfamiliar caves can be dangerous for untrained people. That’s why it’s important to never go alone and always have a trained cave guide. Almost 100 years ago, young cave explorer Floyd Collins was searching a new passageway and became trapped. Even though this was before internet, his story became the very first “viral” story that went around the world through the brand-new technology of broadcast radio. Today, you can see Sand Cave, where he was trapped that is near the entrance of Mammoth Cave National Park.

You can also visit beautiful Mammoth Onyx Cave that was discovered by 10-year-old Martha Woodson. Her brothers later explored the cave with her in 1799, more than 200 years ago. This cave is located in the small town of Horse Cave, on the property of Kentucky Down Under Adventure Zoo in where you can even pet a kangaroo!

Petting a kangaroo at Kentucky Down Under Adventure Zoo

5. Are there animals in caves?

Some animals like to hang out in the entrance of caves, but they don’t truly live inside of caves. These animals are called troglophiles, and they include mammals like foxes and bears, insects like spiders and cockroaches, and reptiles like salamanders and frogs. Some troglophiles want to escape from the heat in a shady spot, and some use the cave entrance for safety, sleeping, or hibernation. Certain birds like swallows and owls may use cave entrances for nesting.

The true cave dwellers are the troglobites. These are animals that live inside of caves and never go outside. They have usually adapted or adjusted to life inside a cave with physical changes like reduced or no vision and a loss of color. For example, blind cave fish have no eyes and no coloring.

Bats aren’t actually troglobites because they only use caves for sleep and reproduction. They frequently leave the cave to hunt food. Also, despite popular rumors, bats are not blind.

The American Cave Museum in the Hidden River Cave complex has interesting exhibits about cave animals. And you may even find some on your cave tour!

Cave Salamander

6. What are caves used for?

Years ago, some caves were used for shelter. Because the temperature inside caves is about 58 degrees or below, caves have been used to store food like vegetables. Sometimes people gathered at the mouths of the caves during hot weather to enjoy the cool air. In 1839, Dr. John Croghan set up a tuberculosis hospital in Mammoth Cave, but that did not prove to be successful.

Dr. George A. Thomas built a system to provide water from the underground river at Hidden River Cave and another system to generate electricity for the small town of Horse Cave, making it the first city in Kentucky outside Louisville to have electricity and the very first in the state to have incandescent street lights.

Of course, caves have also been exciting tourism attractions. Mammoth Cave has been open for tourists for more than 200 years, making it the second-oldest tourist destination in the United States, just after Niagara Falls

Hidden River Cave in downtown Horse Cave, Kentucky

7. Can you tell if you are standing on a cave?

Caves are usually far underneath your feet, and you can’t tell where they go. But in downtown Horse Cave, the pathway of Hidden River Cave is outlined in the sidewalk in aggregate (a pebbly concrete). You can stand “on the cave or off the cave”!

The award-winning Horse Cave Stories Cell Phone Tour takes you around the above-ground pathway of Hidden River Cave. You can use your cell phone to hear stories from locals about how a cave grew on top of a cave and about what’s underneath your feet. And you can go to the Horse Cave Stories website to hear more stories and see cool photos.

Horse Cave Stories Cell Phone Tour

Some info from, Kentucky Down Under Adventure Zoo/Mammoth Onyx Cave, Mammoth Cave Biosphere Preserve, Hidden River Cave/American Cave Museum, and