Features
Society dictates that we have homes within neighborhoods. We have neighborhoods within towns and cities, and those within counties. Each entity serves to make whole the next largest. That’s the way a society, an ecosystem, works. 
In certain parts of the state, underneath the earth’s surface, holes in the ground form their own societies. Species that the vast majority of Oklahoma residents has never laid eyes on – and never will – dwell there, have for hundreds of millions of years. They live in their separate caves that join with one another through cracks and crevices to form one ecosystem. These species live and die underground in caves that are known, and ones that have yet to be discovered.
The Formations
Oklahoma’s underground terrain is as diverse as the state’s surface. Nine named cave regions exist within Oklahoma’s borders, each one unique in its mineral compostion. Perhaps the most well known cave in the state, Alabaster Caverns, is situated in the Cimmaron Gypsum Hills in northwest Oklahoma. A traditional gypsum cave, Alabaster is the largest of its kind in the world that is open to the public.
Mike Caywood, park manager of Alabaster Caverns State Park in Freedom, Okla., says the Cimmaron Gypsum caves are fed their water source by aquifers in Colorado, and that the caves have been formed over the years by the force of water carving its way through the ground.
“The caves in western Oklahoma began formation during the Permian (Era),” says Roosmarijn Tarhule-Lips, a former professor of geography at the University of Oklahoma.
Around 250 million years ago, the area that is now western Oklahoma was the western shore of an inland sea that reached to New Mexico and parts of west Texas. As the sea began to evaporate, Tarhule-Lips says, the salt in the water concentrated, eventually crystallizing into the gypsum and salt deposits that scatter the countryside.
“These gypsum and salt deposits are very soluble,” says Tarhule-Lips. “Rainwater would dissolve them, but because western Oklahoma is so arid, it hasn’t all eroded or dissolved. But where it has eroded away is where you find breaks into the cave system.”
Across the state, on the eastern side, ancient limestone caves make up the Springfield Plateau, a region of caves that is fed by aquifers from the Ozark Mountains and is part of the larger Ozark cave system.
Much older than western Oklahoma’s gypsum caves, the limestone caves in northeast Oklahoma formed during the Cambrian Era, which predates the Permian Era by approximately 300 million years. Caves were formed in the limestone that is abundant in the northeast part of the state. Over millions of years, water sources penetrated cracks in the relatively porous rock, slowly dissolving the calcium carbonate that makes up limestone. The calcium carbonate then redeposited on the ceilings and floors of the caves through evaporation and precipitation, forming the stalagmites, stalactites and other formations found in these caves.
“At one time, the Ozark Mountains were an island of volcanic rock and sediment in what would have been the Gulf of Mexico, and at the bottom of the ocean there were sand deposits and, in deeper water, fallout of skeletons of animals that dwelled in the ocean,” Tarhule-Lip says, which compressed with other minerals to form the limestone.
“The (Springfield Plateau) is located on the western edge of the Ozarks,” says Hensley. “We probably have more caves in this area than most folks realize.”
Hensley says that these limestone caves remain closed to the public because many are on private land, and often those passing through have to crawl through tight passages that connect the larger cave rooms.
“The limestone caves are more interconnected (than gypsum caves),” adds Mark Howery, a wildlife diversity biologist for the Oklahoma Department of Wildlife Conservation.
Howery says that some very small species living inside the caves could traverse the entire Ozark cave system through these passages.
The Species
Life inside of the cave regions is just as diverse as the composition of the caves themselves, according to Howery. Though the caves do share a couple of species of bats – the Big brown bat and the Eastern Pipistrelle included – the majority of the state’s gypsum and limestone cave dwellers have little in common. Howery points out that the state’s two major cave systems are separated by a 250-mile swath of land that passes through the heart of Oklahoma. It is this physical separation, he says, that has played a large part in the diversity of species that call the caves home.
“Bats in the Ozarks tend to be forest-dwelling,” he says. “While bats found in the western part of the state have adapted to foraging over open country for food.”
Several bat species found in the Southwest meet their eastern-most boundary along the gypsum caves in western Oklahoma, while Southeast bat species meet their western-most boundary in the Springfield Plateau, Howery says.
Limestone
The limestone caves are home to many rare, threatened and endangered species, according to Hensley. Among the species that call these Ozark caves home are several species of bats, fish, arthropods, isopods and salamander.
“There are several endangered species (in the limestone caves),” Howery explains. “Several are so rare, in fact, that they may only be found in one cave.”
Hensley says the U.S. Fish and Wildlife Service has directed a lot of its management to the Ozark big-eared bat, the rarest mammal in Oklahoma.
“The Ozark big-eared bat is here (in northeast Oklahoma) year round,” he says. “These bats are so rare, there are only 1,800 left in the world. Caves are important to them, as well as the forest and foraging areas around the caves.”
The gray bat is another species that dwells in the limestone caves. Currently on the endangered species list, Hensley is cautiously optimistic about the bats’ repopulation. Efforts to preserve the species’ 10 maternity caves and nine hibernating caves have paid off.
“The gray bat has come back very well,” he remarks.
Due to groundwater quality issues, several aqueous species that dwell in the Ozark caves are categorized as species of concern, including two species of blind cave crayfish and the Ozark cavefish.
“In northeast Oklahoma, surface water and ground water are so closely connected that it’s hard to separate the two,” he notes. “Cave fish and crayfish are very susceptible to water quality issues that affect groundwater, like limestone residue and septic tank and municipal development runoff.”
Hensley says that the Fish and Wildlife Service works closely with private landowners along with state and tribal agencies to ensure that all steps are taken to preserve the cave ecosystem.
Gypsum
Gypsum caves are home to five species of bats, along with salamanders, crayfish and cave crickets.
“(Gypsum) caves are popular with bats in the summertime because they are shallower, warmer,” Howery says, adding that the bats that live in western Oklahoma caves prefer the drier climate.
The Mexican free-tailed bat spends its summers in the gypsum caves of Oklahoma. More than four million bats annually make the trek north to one of five colonies in the state. The second largest colony is found in the Selman Cave, which hosts around one million bats.
“Most bat colonies host anywhere from six to 200,” Howery explains. “There are only a few that have more than 1,000.”
To put the number of Mexican free-tailed bats that migrate north to the gypsum caves each year in perspective, Howery points out that there aren’t even a million bats that live in the entire Springfield Plateau region in northeast Oklahoma.
“The Selman bat cave entrance is about 60 feet wide and 30 feet high, so many bats can fly in and out at the same time,” he says.
Each summer, the Oklahoma Department of Wildlife hosts bat watches at Selman to allow spectators to watch the bats take off from the cave at dusk to dine on insects. The other colonies of Mexican free-tailed bats are all located on private lands.
Preservation
“Take nothing but pictures, leave nothing but footprints, kill nothing but time.”
The caver’s motto, as it’s called, sums up the attitudes of those who are most vested in protecting and preserving the state’s caves.
The preservation of Oklahoma’s caves is mandatory in saving many species from extinction. And for federal and state agencies that are working to preserve these geological gems, there’s no better tool to save the cave than education.
“One of our goals is to educate people on why caves are important, as well as why it’s necessary to preserve (the cave’s) surroundings and to have good ground cover. There are unique critters living in those holes, but the surrounding forest and aquifers are necessary parts of the cave, too,” comments Hensley.
He says that agencies such as the Forest and Wildlife Service rely on the help of cavers affiliated with the National Speleological Society to help in the mapping and preservation of Oklahoma’s caves.
Caver Duane Del Vecchio is a member of the Central Oklahoma Grotto, a local chapter affiliated with the NSS.
“I joined COG for the science aspect,” Del Vecchio says. “I would say (the club is) more into research than recreation or sport. Yes it is fun, but we can be helping people via mapping or counting or other means. Many times if you are recreational caving, you sometimes go though a cave so quickly that you miss a lot of neat and exciting items. When you map, you literally are seeing just about every foot of a cave in detail.”
Fellow COG member Dale Amlee says that the thrill of discovery is what keeps him interested in caving.
“I find that crawling through caves feels sort of like navigating a very intricate three-dimensional maze,” he says. “The interrelated passageways, the ways in which the water flows from one arm or chamber to the other, the twists and turns leading to surface entrances – it all creates excitement.
“There are many caves in Oklahoma that are not much more than muddy, nasty, slimy, painfully uninteresting crawls through the earth,” he adds. “Then there are a wide variety of interesting, pretty caves with numerous features, which make a trip through them very pleasant.”
The Plight of the Gray Bat
The gray bat is an endangered species that occupies caves in northeast Oklahoma. Due to factors including human disturbance, loss and degradation of habitat and cave commercialization, the gray bat was placed on the endangered species list in 1976. Efforts to allow the bats to replenish their population have been successful, and Steve Hensley, Ozark Plateau National Wildlife Refuge manager, says that the gray bat may soon be removed from the endangered list.
However, the bats are currently facing another crisis. White-nose Syndrome, a fungus that hosts on hibernating bats, has become a concern for the gray bat population. The fungus is widespread in the Northeast, but could be traveling toward hibernating bats in the Southeast U.S. Because of high concentrations of gray bats in those states – nearly half of the entire gray bat population hibernates in a single cave in Alabama – Hensley says that all efforts to remove the gray bat from the endangered list have been halted in order to ensure that White-nose Syndrome doesn’t ravage the population.
“This winter will really tell how widespread the disease has been,” Hensley says. “And whether it made it to the gray bat population.”
Hensley estimates that 150,000 gray bats spend their summer in Oklahoma caves.
In certain parts of the state, underneath the earth’s surface, holes in the ground form their own societies. Species that the vast majority of Oklahoma residents has never laid eyes on – and never will – dwell there, have for hundreds of millions of years. They live in their separate caves that join with one another through cracks and crevices to form one ecosystem. These species live and die underground in caves that are known, and ones that have yet to be discovered.
The Formations
Oklahoma’s underground terrain is as diverse as the state’s surface. Nine named cave regions exist within Oklahoma’s borders, each one unique in its mineral compostion. Perhaps the most well known cave in the state, Alabaster Caverns, is situated in the Cimmaron Gypsum Hills in northwest Oklahoma. A traditional gypsum cave, Alabaster is the largest of its kind in the world that is open to the public.
Mike Caywood, park manager of Alabaster Caverns State Park in Freedom, Okla., says the Cimmaron Gypsum caves are fed their water source by aquifers in Colorado, and that the caves have been formed over the years by the force of water carving its way through the ground.
“The caves in western Oklahoma began formation during the Permian (Era),” says Roosmarijn Tarhule-Lips, a former professor of geography at the University of Oklahoma.
Around 250 million years ago, the area that is now western Oklahoma was the western shore of an inland sea that reached to New Mexico and parts of west Texas. As the sea began to evaporate, Tarhule-Lips says, the salt in the water concentrated, eventually crystallizing into the gypsum and salt deposits that scatter the countryside.
“These gypsum and salt deposits are very soluble,” says Tarhule-Lips. “Rainwater would dissolve them, but because western Oklahoma is so arid, it hasn’t all eroded or dissolved. But where it has eroded away is where you find breaks into the cave system.”
Across the state, on the eastern side, ancient limestone caves make up the Springfield Plateau, a region of caves that is fed by aquifers from the Ozark Mountains and is part of the larger Ozark cave system.
Much older than western Oklahoma’s gypsum caves, the limestone caves in northeast Oklahoma formed during the Cambrian Era, which predates the Permian Era by approximately 300 million years. Caves were formed in the limestone that is abundant in the northeast part of the state. Over millions of years, water sources penetrated cracks in the relatively porous rock, slowly dissolving the calcium carbonate that makes up limestone. The calcium carbonate then redeposited on the ceilings and floors of the caves through evaporation and precipitation, forming the stalagmites, stalactites and other formations found in these caves.
“At one time, the Ozark Mountains were an island of volcanic rock and sediment in what would have been the Gulf of Mexico, and at the bottom of the ocean there were sand deposits and, in deeper water, fallout of skeletons of animals that dwelled in the ocean,” Tarhule-Lip says, which compressed with other minerals to form the limestone.
“The (Springfield Plateau) is located on the western edge of the Ozarks,” says Hensley. “We probably have more caves in this area than most folks realize.”
Hensley says that these limestone caves remain closed to the public because many are on private land, and often those passing through have to crawl through tight passages that connect the larger cave rooms.
“The limestone caves are more interconnected (than gypsum caves),” adds Mark Howery, a wildlife diversity biologist for the Oklahoma Department of Wildlife Conservation.
Howery says that some very small species living inside the caves could traverse the entire Ozark cave system through these passages.
The Species
Life inside of the cave regions is just as diverse as the composition of the caves themselves, according to Howery. Though the caves do share a couple of species of bats – the Big brown bat and the Eastern Pipistrelle included – the majority of the state’s gypsum and limestone cave dwellers have little in common. Howery points out that the state’s two major cave systems are separated by a 250-mile swath of land that passes through the heart of Oklahoma. It is this physical separation, he says, that has played a large part in the diversity of species that call the caves home.
“Bats in the Ozarks tend to be forest-dwelling,” he says. “While bats found in the western part of the state have adapted to foraging over open country for food.”
Several bat species found in the Southwest meet their eastern-most boundary along the gypsum caves in western Oklahoma, while Southeast bat species meet their western-most boundary in the Springfield Plateau, Howery says.
Limestone
The limestone caves are home to many rare, threatened and endangered species, according to Hensley. Among the species that call these Ozark caves home are several species of bats, fish, arthropods, isopods and salamander.
“There are several endangered species (in the limestone caves),” Howery explains. “Several are so rare, in fact, that they may only be found in one cave.”
Hensley says the U.S. Fish and Wildlife Service has directed a lot of its management to the Ozark big-eared bat, the rarest mammal in Oklahoma.
“The Ozark big-eared bat is here (in northeast Oklahoma) year round,” he says. “These bats are so rare, there are only 1,800 left in the world. Caves are important to them, as well as the forest and foraging areas around the caves.”
The gray bat is another species that dwells in the limestone caves. Currently on the endangered species list, Hensley is cautiously optimistic about the bats’ repopulation. Efforts to preserve the species’ 10 maternity caves and nine hibernating caves have paid off.
“The gray bat has come back very well,” he remarks.
Due to groundwater quality issues, several aqueous species that dwell in the Ozark caves are categorized as species of concern, including two species of blind cave crayfish and the Ozark cavefish.
“In northeast Oklahoma, surface water and ground water are so closely connected that it’s hard to separate the two,” he notes. “Cave fish and crayfish are very susceptible to water quality issues that affect groundwater, like limestone residue and septic tank and municipal development runoff.”
Hensley says that the Fish and Wildlife Service works closely with private landowners along with state and tribal agencies to ensure that all steps are taken to preserve the cave ecosystem.
Gypsum
Gypsum caves are home to five species of bats, along with salamanders, crayfish and cave crickets.
“(Gypsum) caves are popular with bats in the summertime because they are shallower, warmer,” Howery says, adding that the bats that live in western Oklahoma caves prefer the drier climate.
The Mexican free-tailed bat spends its summers in the gypsum caves of Oklahoma. More than four million bats annually make the trek north to one of five colonies in the state. The second largest colony is found in the Selman Cave, which hosts around one million bats.
“Most bat colonies host anywhere from six to 200,” Howery explains. “There are only a few that have more than 1,000.”
To put the number of Mexican free-tailed bats that migrate north to the gypsum caves each year in perspective, Howery points out that there aren’t even a million bats that live in the entire Springfield Plateau region in northeast Oklahoma.
“The Selman bat cave entrance is about 60 feet wide and 30 feet high, so many bats can fly in and out at the same time,” he says.
Each summer, the Oklahoma Department of Wildlife hosts bat watches at Selman to allow spectators to watch the bats take off from the cave at dusk to dine on insects. The other colonies of Mexican free-tailed bats are all located on private lands.
Preservation
“Take nothing but pictures, leave nothing but footprints, kill nothing but time.”
The caver’s motto, as it’s called, sums up the attitudes of those who are most vested in protecting and preserving the state’s caves.
The preservation of Oklahoma’s caves is mandatory in saving many species from extinction. And for federal and state agencies that are working to preserve these geological gems, there’s no better tool to save the cave than education.
“One of our goals is to educate people on why caves are important, as well as why it’s necessary to preserve (the cave’s) surroundings and to have good ground cover. There are unique critters living in those holes, but the surrounding forest and aquifers are necessary parts of the cave, too,” comments Hensley.
He says that agencies such as the Forest and Wildlife Service rely on the help of cavers affiliated with the National Speleological Society to help in the mapping and preservation of Oklahoma’s caves.
Caver Duane Del Vecchio is a member of the Central Oklahoma Grotto, a local chapter affiliated with the NSS.
“I joined COG for the science aspect,” Del Vecchio says. “I would say (the club is) more into research than recreation or sport. Yes it is fun, but we can be helping people via mapping or counting or other means. Many times if you are recreational caving, you sometimes go though a cave so quickly that you miss a lot of neat and exciting items. When you map, you literally are seeing just about every foot of a cave in detail.”
Fellow COG member Dale Amlee says that the thrill of discovery is what keeps him interested in caving.
“I find that crawling through caves feels sort of like navigating a very intricate three-dimensional maze,” he says. “The interrelated passageways, the ways in which the water flows from one arm or chamber to the other, the twists and turns leading to surface entrances – it all creates excitement.
“There are many caves in Oklahoma that are not much more than muddy, nasty, slimy, painfully uninteresting crawls through the earth,” he adds. “Then there are a wide variety of interesting, pretty caves with numerous features, which make a trip through them very pleasant.”
The Plight of the Gray Bat
The gray bat is an endangered species that occupies caves in northeast Oklahoma. Due to factors including human disturbance, loss and degradation of habitat and cave commercialization, the gray bat was placed on the endangered species list in 1976. Efforts to allow the bats to replenish their population have been successful, and Steve Hensley, Ozark Plateau National Wildlife Refuge manager, says that the gray bat may soon be removed from the endangered list.
However, the bats are currently facing another crisis. White-nose Syndrome, a fungus that hosts on hibernating bats, has become a concern for the gray bat population. The fungus is widespread in the Northeast, but could be traveling toward hibernating bats in the Southeast U.S. Because of high concentrations of gray bats in those states – nearly half of the entire gray bat population hibernates in a single cave in Alabama – Hensley says that all efforts to remove the gray bat from the endangered list have been halted in order to ensure that White-nose Syndrome doesn’t ravage the population.
“This winter will really tell how widespread the disease has been,” Hensley says. “And whether it made it to the gray bat population.”
Hensley estimates that 150,000 gray bats spend their summer in Oklahoma caves.
