Cave Adventures in the Driftless

Kickapoo Cavern walls

For those in the know, southeastern MN and southwestern WI hold a wealth of cave systems - many yet undiscovered and unexplored. Others were discovered in the 19th and 20th centuries and were developed into tourist attractions. While some of these caves continue as commercial businesses, two caves I recently went through on guided tour - Mystery Cave near Preston MN and Kickapoo Caverns near Wauzeka WI - have been protected and are either offered to the public as part of the MN state park system or protected by the Mississippi Valley Conservancy (MVC) and used as research areas to help support declining bat populations.

The Driftless and Driftless-like parts of both MN and WI have a unique geology - karst.  According to the Forestville/Mystery Cave park's website,  "Karst occurs in areas of soluble rocks, usually limestone or dolomite. As rainwater percolates through the soil, it is rendered slightly acidic as it picks up carbon dioxide from microbial decay of organic soil material. This fortified water has the capacity to dissolve the rock. The effects of this dissolving action are minute from the perspective of a human’s lifetime. However, over the course of many thousands of years, dramatic changes occur; the typical features of karst develop – caves and sinkholes form; underground drainage occurs." 

The caves that formed over this time are used by bats as hibernucula from late October until early May. In the warm months in between, the caves are open for human visitors like us.

Heading deep into
Kickapoo Cavern

I was fortunate to register for the annual Mississippi Valley Conservancy Kickapoo Cavern Bat Ecology tour day in July. This is a one-day, once-a-year opportunity. The cave system is one of Wisconsin's longest natural cave systems. Once a tourist destination, the tour starts through the same door tourists used in the rustic old visitor center. The Mississippi Valley Conservancy works with the WI DNR and universities who are studying how the cave's population of bats (little brown; northern long-eared; and eastern pipistrelle) have been able to maintain their numbers despite the devastation of whitenose syndrome that has ravaged up to 90% of bat populations in other caves.

150 year old "baby" stalactites

The cave itself features "rooms" - the Register room where early explorers and tourists would write their names on the walls with graphite; the Cathedral room with 40 ft ceiling and a long straight cavern that could contain crowds; the Pipistrelle Pool room with its large, still pool. In the early days, explorers would break off stalactites and stalagmites as souvenirs so many of those lovely features are gone. Instead, we see 1"-3" "babies" forming. These babies are over 150 years old.

Calcium-rich water drops

Throughout the tour, we could hear the slow drip of droplets from rain and groundwater  around us.  The water continues it's millennial work of wearing away the limestone and dolomite to create more cracks and openings. Seeing the cave through the eyes of the bat ecologists who guided us was also a powerful learning experience. You too can take the tour through this video made by the MVC

Old road sign displayed
in the Mystery Cave Visitor Center

On our hike to Forestville State Park  recently, we took the opportunity to tour at the park's Mystery Cave. The Mystery Cave, also once a tourist attraction, was only discovered in the late 1930s. At 13 miles of caverns, it is the longest cave so far discovered in Minnesota. It was acquired by the MN DNR in the late 1980s, modernized and his open daily for tours from May-October when the bats are gone. The modern visitor's center has great informational displays explaining the geology and bat bat population.

Pyrite revealed under
black light

Our tour took us through only about a half mile of the cave system. An interesting feature of the cave is that the ceilings are naturally smooth and almost squared off. It looks like it has been constructed. A tree root visible in a crack in the ceiling while we were 34 feet underground spoke to the living forces that help explain how persistent life is and how water and roots changes all landscapes - even caves!

The small white dots in the water above
are blind springtails under a 
cluster of botryoids

There is small and microscopic life in the cave. We were surprised to see a small pool containing tiny white dots - these are small blind springtails that live off dust - and human hair! Apparently kids love to hear that. I understand, they leave alot of food!

We had a chance to see a cephalopod fossil in the ceiling, pyrite and colored rock under black light, a large still pool, and rock formations called cave bacon that put us in mind of the "ice bacon" we saw at Vetsch park last winter. The rock formations this ribbony bacon formed on were alike in the cave and the rocks in Vetsch. Nature's patterns are strong!

Both tours gave me a ton of information that help me better understand karst geology and the role of caves as hibernacula for bats. I can't recommend this kind of learning highly enough.