As I peered over the edge, 75 feet to the rocky bottom, my heart raced. Our survey team’s gear was triple checked by some of the most experienced vertical cavers to ensure our safety. As I slowly rappelled down, the sunlight gave way to darkness and a musty, earthy odor that cavers know well. With my feet finally finding the safety of the cave floor, I wiggled out of the harness and waited until the others made the same journey.
With our heart rates calming, we aimed our headlamps in different directions and revealed hundreds of thousands of bats carpeting the cave walls. Nearly 500,000 endangered gray bats call the cave home in the winter, serving as Missouri’s largest gray bat hibernaculum and one of the largest throughout the gray bat’s range.
After spending less than an hour in the cave, we began the ascent back to the top. As I took breathing breaks on the ascent, I noticed the walls of the cave are mantled in mosses. This made me think, what other cave life are we missing as we explore these caves?
Missouri Cave Basics
Of Missouri’s 80-plus natural communities, caves seem the most alien, hosting just as alien-looking creatures, found nowhere else on earth. While Missouri is dubbed “The Cave State” because of the number of “show caves,” Missouri still is second to Tennessee, which claims over 10,000 natural caves. Missouri’s caving community adds more caves and mapped passage to the list each year. With each passing year, more caves are discovered but at present over 7,500 caves are known for Missouri. How many more are waiting to be discovered?
The definition of a cave varies by state, but the Missouri Speleological Survey defines a cave as “any natural feature within bedrock enterable by humans for an appreciable distance.”
Missouri caves consist of air-filled underground openings generated in limestone, dolomite, or more rarely, sandstone. Karst features, including caves, form when carbon dioxide from the air mixes with rainwater, dead plant material, and soil. As the slightly acidic water moves through the rock, it dissolves and creates cracks and openings. Most of the average rock that makes up Missouri’s caves are between 300 to 500 million years old.
Like a snowflake, each cave is unique. They vary in their difficulty to explore, variety of cave formations, geologic composition, diversity of cave life, and extent of passage.
Some caves are completely barren of formations, also known as speleothems, whereas other caves display an extravagant array of beautiful formations. Stalactites are formations that begin on the ceiling of the cave, and stalagmites are formations that begin on the ground/floor of the cave. Other cave formations include columns, cave bacon, rimstone dams, cave pearls, draperies, soda straws, helictites, and more.
Missouri’s caves range in length from 20 feet to more than 30 miles of mapped passage. With its abundance of soluble stone, the Missouri Ozarks harbor the greatest density of caves. With over 730 recorded caves, Shannon County holds the title for most caves for a single county in Missouri.
Most, but not all, caves are comprised of three basic zones:
The Entrance Zone: Often called “the dripline,” many plant species are found here, including mosses, ferns, and liverworts. Animals may retreat to the entrance zone to cool off on a hot day. Eastern phoebe nests, cave orb weaver spiders, fishing spiders, and surface-dwelling millipedes are also found commonly at the entrance zone.
The Twilight Zone: Most cave life resides just past the entrance, but where sunlight is still visible. Some species of birds, such as turkey vultures and owls, nest here. Snakes may slither this far back and surprise an inattentive caver. Cave salamanders, western slimy salamanders, and pickerel frogs are some of the most common amphibians frequenting this zone. Shining your light on the walls may reveal the striking yellow or silvery sparkle of chemolithoautotropic bacteria (CLAT) as far as 1,000 feet into the cave. These bacteria get the energy they need from the chemicals in the cave rock.
The Dark Zone: This is total darkness and home to endemic creatures (found nowhere else on earth). Adapted to living in complete darkness, some of these animals are blind and white or translucent in appearance. However, other creatures, such as gray bats, form large colonies in the dark zone. Their guano provides food for many cave creatures such as rove beetles, pseudoscorpions, and grotto salamanders.
Cave Life Definitions
Trogloxene: cave visitor, utilizes caves at some point in their life, but also lives outside of caves (raccoons, bats)
Troglophile: can complete lifecycles both inside and outside of caves (cave salamander, slimy salamander)
Stygophile: aquatic troglophile (some species of amphipods, isopods, and planaria)
Troglobite: spends its entire life inside a cave in total darkness; blind, white, or transparent in color (grotto salamander)
Stygobite: aquatic troglobite (Ozark cavefish, Salem cave crayfish)
Missouri Cave Life
Missouri’s caves host over 1,100 known species, including amphibians, reptiles, mammals, birds, fish, and a variety of invertebrates. Evidence of many Pleistocene mammal fossils and signs, such as direwolf, flat-headed peccary, American lion, and jaguar, among others, have been found in Missouri’s caves. While some cave creatures, like inquisitive raccoons, only visit a cave for a short period of time, many of the creatures in Missouri’s caves spend their entire lives in caves.
Some cave-dwelling species are only found in one cave in the entire world, while others are found throughout the Ozarks and the Midwest and beyond. Missouri has many endemic cave species, or those found nowhere else on earth, including the grotto sculpin, Tumbling Creek cavesnail, and many other invertebrates. Cave invertebrates are not well studied in Missouri and are considered species of conservation concern.
Where there’s smoke there’s fire, and people often think where there are caves there are bats. While bats play a vital role in cave ecology, not all caves are suitable for bats. Seven bat species depend on Missouri caves. The once common tri-colored bat (Perimyotis subflavus) has declined in Missouri rapidly, due to white-nose syndrome. With 1-inch-long ears equipped for detecting moths, the federally endangered Ozark big-eared bat (Corynorhinus townsendii ingens) has not been officially documented in Missouri since the 1970s.
An estimated 800,000 gray bats (Myotis grisescens), a federally endangered bat, is holding strong throughout its range, including in the Show-Me State. A strong scent of ammonia wafting out of cave entrances in Missouri signals the presence of gray bats.
Gray bats play a vital role in Missouri’s cave ecology. They are the only bat in Missouri that reside in caves year-round, so their guano piles can be immense. Often gray bat caves are some of the most biodiverse. Grotto salamanders, cave-adapted springtails, rove beetles, cave-adapted millipedes, pseudoscorpions, and many other species of invertebrates benefit from the guano piles. The most biodiverse cave west of the Mississippi is currently Tumbling Creek Cave, which also happens to be the most studied cave in Missouri with at least 115 known species.
White-Nose Syndrome and Amphibian Chytrid Fungus
White-nose syndrome (WNS), an invasive fungal disease in bats, was discovered in New York in the winter of 2006–2007. The newly described fungus (Pseudogymnoascus destructans) made its way to the United States from Eurasia and spread quickly throughout the United States and Canada, killing millions of hibernating cave bats. While we do not know exactly how the fungus arrived in the United States, we know that protecting caves from extra disturbance while the bats are hibernating is giving the bats an extra fighting chance.
Cleaning gear and clothing between caves not only may prevent the spread of WNS, but it also helps prevent the spread of amphibian chytrid fungus.
Getting Involved and Protecting Caves
With many Missouri cave species under threat, protecting caves and their cave life is more important than ever. While it isn’t conducive to gate every cave, some caves benefit from a gate to protect designated natural areas, protect federally endangered species, and protect human safety. Protecting water quality not only helps surface plants and animals, but healthy water will ensure that subsurface creatures are also healthy. Caves should only be accessed through landowner permission. Always remember the caver’s motto — “Take nothing but pictures, leave nothing but footprints, kill nothing but time.”
Beginning in 2010, all caves on MDC land were closed to public access, to protect hibernating bats from the deadly white-nose syndrome (WNS). Since that time, select MDC-owned caves across the state were recently opened to limited, guided, public programs and tours.
With so much more to explore and document in Missouri caves, there are a variety of opportunities to get involved with mapping, monitoring, and inventorying these subterranean worlds. There are many caving organizations, referred to as grottos, all over Missouri. These organizations offer members opportunities to learn more about caves as well as exploring and monitoring. Statewide organizations include the Missouri Bat Census, Missouri Caves and Karst Conservancy, Missouri Speleological Survey, and the Cave Research Foundation.
Since MDC owns more than 300 caves, it is a daunting task to monitor all of them. Through a cooperative agreement, the Cave Research Foundation surveys, monitors, and maps MDC caves. This gives the public opportunities to see some of MDC-owned caves by conducting citizen science monitoring.
Please note that MDC-owned caves are still closed to public access except through the Cave Research Foundation and our educational programs. Please visit mdc.mo.gov/events and search “cave” for upcoming cave programs. To get involved with the Cave Research Foundation in Missouri, please visit short.mdc.mo.gov/4fG.
Also In This Issue
This Issue's Staff
Editor - Angie Daly Morfeld
Associate Editor - Larry Archer
Photography Editor - Cliff White
Staff Writer - Kristie Hilgedick
Staff Writer - Joe Jerek
Staff Writer – Dianne Van Dien
Designer - Shawn Carey
Designer - Marci Porter
Photographer - Noppadol Paothong
Photographer - David Stonner
Circulation - Laura Scheuler