Dunes 101: Did you know?
I’m Ranger Matt, here at the Indiana Dunes, and I’d like to share with you some of my favorite fun facts about dunes environment, ecology, and history. Stay till the end, and I’ll share a special secret!
Origin of the dunes
Do you know what spawned the dunes and their diverse ecosystem? I’ll give you a hint: it was 300 feet high and moved very slowly. Glacially slow. That’s right! Over 10,000 years ago, glaciers receded north, leaving rolling hills, wetlands, Lake Michigan, and the dunes ridgeline.
Birthplace of ecology
I’ll bet you didn’t know that it was this specific ecosystem that was the birthplace of the science of ecology—that’s the study of organisms and how they relate to one another and their physical surroundings. You can thank Henry Chandler Cowles for that!
You can also thank environmentalist groups and individuals who helped establish the State Park and National Park. After a decade-long battle, Congress established both the Port of Indiana and the National Park.
Dunes, of course, are made of sand, but what is sand made out of? The sand itself is mostly made out of quartz and silica left behind by glaciers. Its composition creates an interesting sound when you walk on it, which is why we call it “singing sands.” There are only a few other places in the world that have singing sands, like Dubai and Japan.
Types of dunes
There are two types of dunes: foredunes and blowout dunes. Foredunes are close to the beach and covered in vegetation like marram grass. This makes for a more stabilized dune and allows even more plant life to thrive. Blowout dunes are caused by intense winds that rip the dunes apart. The loose sand makes a “living dune,” that can move up to several feet every year! Blowout dunes can sometimes be the result of unapproved trails, or social trails, which gradually turn into bigger and bigger areas of sand. So, please check your map to make sure you are on approved trails only!
Old pieces of driftwood and fallen trees make up what the locals call “tree graveyards.” Their dried, gray wood looks kind of spooky, but they’re pretty cool!
Do you know what saltation means? It’s the movement of sand by turbulent air and water flow, and it happens all along our beaches. The sand piles up and eventually forms larger dunes, like Mt. Tom, the tallest dune in the area at 192 feet!
This whole area may look like a desert, but it is freezing and snowcovered for several months out of the year. Not exactly the ideal place for a cactus—or is it? The prickly pear cactus thrives because of the dunes’ desert-like sand. For cacti to thrive, they need well-drained sand and lots of sun. We have plenty of both here at the dunes. We also have more variety of orchids than all of Hawaii!
Another little-known fact is that the Indiana Dunes are full of unique carnivorous plants! Have you heard of a narrow-leaved sundew or a purple pitcher plant? Like the well-known venus fly-trap, these are killer plants that feed on small insects thanks to their clever adaptations. You can find these little meat eaters at Pinhook Bog.
One of my favorite dunes critters is a six-lined racerunner. They can dart around at up to 18 miles-per-hour—that’s almost as fast as an Olympic sprinter! Also native to the area is the gorgeous red fox. They have ears so sensitive that they can hear a mouse scratching a leaf 150 feet away. On top of that, more than 370 species of birds live or migrate through the dunes every single year. At certain times of the year, this is one of the best birding destinations in the nation. There is even a species of frog that has learned to preserve heat in its cells to make it through the frozen winters! But probably the most hard-working animal in the dunes is the dune beaver. We see them working on their dams every hour between dusk and dawn.
The French Polygala is really something special. It only grows on the northern slope of one specific dune, and nowhere else in Indiana. Its common name is Gaywing because it almost looks like it could take flight! Because it’s an endangered species, I’m going to keep its exact location secret.
These are just a few of my favorite fun facts about the Indiana Dunes. If you see me, or any other ranger, ask us questions! We have lots more to share. We also have a Nature Center and ranger-led tours and programs throughout the year.
For more tips and planning tools, get a copy of our Activities Guide at Indiana Dunes Visitor Center or online here. And don’t forget to SUBSCRIBE to our YouTube channel so you can get the most out of our Dunes 101 video series!