From time immemorial, caves have been a place of habitation, a place of refuge, a place of terror or a place of unique wonders, a place that a bevy of literature has been written about often featuring fictional civilizations that may have evolved or lived underground. The Hopi creation story features tribal ancestors that climbed up through caves with the animals to reach the surface of the earth. Some UFO researchers believe Dulce Base in New Mexico is staffed by humans and aliens working together in a vast underground complex. In folklore, caves are characterized as entrances to other dimensions or to the underworld, or places where the perception of time is altered.
John the Baptist lived in a cave, the Dead Sea Scrolls were found in caves, the wee folk faeries dance in the caves, and Jules Verne told us a fantastic tale about journeying to the center of a hollow earth. Dante used a cave as the setting for hell, the cyclops of Greek mythology lived in a cave, and in Lascaux cave in France there is prehistoric cave art that dates back 17, 000 years. Caves seem to be a subject that has held our fascination over the eons.
Caves have unique geological features and biological residents, specially adapted for living within that environment. For the residents of a cave, they have adapted to a more constant temperature, darkness, and relatively stable humidity levels. In most cave environments food is scarce, so the denizens are dependent on one another for the perpetuation of the food chain. From the guano to the bits of algae, all the scarce resources are put to good use in the cave.
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| Lascoux Cave, France, prehistoric cave art. |
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| Cave dwellings in Matera, Italy |
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| Stalactites ans Stalagmites in a cave. |
Bats come to mind when one thinks of an example of a cave dweller. Bears, skunks, moths, and even people are also known, along with bats as trogloxenes. In Greek this means a “cave-guest”. These are all examples of those who go in and out of a cave, are temporary inhabitants or a species that does not complete its whole life cycle inside of a cave and does not have special adaptations for life solely led in a cave.
Another type of cave dweller is known as a troglophile, meaning “cave-lover”. These are organisms who seek to dwell in the dark zones of the cave. They can live outside the cave but they like the dark places within. Examples are earthworms, beetles, crickets, frogs, salamanders, and crayfish.
The third type of cave dweller is known as the troglobite, or “cave-life”. These are true cave dwellers, they spend their entire life in the cave, in the dark, and cannot survive outside the cave. They have special adaptations for cave life, such as extra long antennae, or special enhanced sensory organs for cave survival and finding what scarce food there is in a cave. They are often blind or have very primitive eyes because for a life in the dark, eyes are not necessary, in fact eyes can be a liability. Cave dwellers are light colored or without pigment because protection from the sun is not needed in the dark of the cave.
Many specialized cave species only live in a particular cave or area of the globe, so they are generally rare species that are highly adapted to their specific environment. Examples of troglobite species are cave scorpions (pseudoscorpions), salamanders, spiders, beetles, snails, crayfish, or blind cave fish.
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| A cave insect, showing lack of pigment. |
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| A cave salamander, with no eyes, they are not needed in the dark. |
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| Blind cave fish. |
Examples of cave dwelling plants would be ferns, moss, liverworts (a primitive type of plant), fungi, cyanobacteria and algae known as troglofauna. Troglofauna can only live in the opening area of the cave or the twilight areas where some light is available, they cannot live in the perpetual dark of the cave.
Some different types of caves that can be found are ice caves, sea caves, solution caves, lava caves, Eolian or wind caves, and sandstone caves or rock shelters.
An example of a specialized ecosystem in a cave can be seen in the Movile Cave in Romania. The cave was discovered in 1986 while workers were scouting out locations for a power plant site. The cave is in the south east part of the country near the Black Sea. This cave has a poisonous atmosphere, there is no light within, the water is sulfuric and contains 100x more carbon dioxide than normal air. There are 48 species that have been found in the cave and 33 of them exist nowhere else on earth.
The water within the cave comes from an underground aquifer. Since there is no water dripping into the cave there are no stalactites or stalagmites in it. A unique frothy foam, resembling tissue paper, exists on the top of the water layer. Living in the foam are organisms called ‘autotrophs’, these organisms are able to form nutrients from simple inorganic substances, such as carbon dioxide. Their life process is based on chemosynthesis, they can create energy from chemical reactions to get the nutrients they need for food. Other microscopic organisms in the cave are classed as ‘methanotrophs’, which means they create methanol and use other substances that dissolve into the water to get their nutrients. Such unique life processes can help us imagine what kinds of microscopic life might be able to exist on other planets in our solar system that do not have an oxygen atmosphere like earth.
There are also troglobites in Movile Cave such as spiders, centipedes, snails, cave scorpions and leeches. The cave has no natural outlet, so it is a specialized environment that was sealed off from the rest of the world until its discovery in 1986.
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| A diver in Movile Cave, Romania. It has no natural outlet and contains 33 species found nowhere else on earth. |
Another interesting cave can be found in the north island of New Zealand. Called Waitomo Caves, they are home to thousands of glow-worms, Arachnocampa luminosa, and they light up the labyrinth of caves with tiny spots of illumination.
Between Scotland and Ireland, Fingal’s Cave can be found. It is a sea cave, formed from ancient volcanic activity and the cave is known for its natural acoustics and contains unique hexagonal columns of basalt called colonnades. Mendelssohn wrote an overture about the cave and it is also connected to Irish and Scottish mythology and considered a one of a kind in the world place. Jules Verne visited the cave when it was a popular tourist attraction in the 1800’s, who knows, maybe it was inspiration for his writings.
This has been the briefest overview of some fascinating facts about cave life and a few remarkable caves. Just hop on your computer or head to your local library to learn more interesting information other famous caves and cave life. A suggested reading list for cave books is found below. 😊
Waitomo Caves, New Zealand 
Fingal's Cave, Scotland 
Lava Beds National Monument, California
Reading Suggestions about Caves and Caving:
Non-Fiction:
“The Secret Cave: Discovering Lascaux”, by Emily Arnold McCully. Ages 6-9 Part “Hardy Boys”, part archeology, this book looks at the discovery of the prehistoric cave paintings of Lascaux, and it invites today’s readers to experience the wonder of the event.
“Caves” (Nature in Action series), by Stephen Kramer. Ages 9+This book is an excellent and nicely illustrated introduction to caves.
“The Hidden World of Caves”, by Ron Kerbo. Ages 8+This little book is illustrated with color photographs and gives a nice introduction to caves and caving.
“Caves and Caverns”, by Gail Gibbons. Ages 6-10 By presenting the types of caves and how they are formed, this book provides simple, straightforward science in picture-book format.
“Blind Descent: The Quest to Discover the Deepest Cave on Earth”, by James M. Tabor. Ages 12+ This book chronicles two separate expeditions to reach the record for the world’s deepest cave. It provides a gripping account of the nature of modern caving expeditions.
“Caves” (Nature in Action) by Stephen Kramer ages 8-12
“Caves” (Learning About Landforms) by Ellen Labrecque ages 6-8
“All Thirteen: The Incredible Cave Rescue of the Thai Boys' Soccer Team” by Christina Soontornvat ages 8-12
Fiction:
“In the Dark Cave”, by Richard A. Watson. Ages 3-7This is a rhyming book about a dark cave and the creatures that live happily in it (without light). One day, an explorer ventures down the cave with light and the creatures do not know what to make of it.
“Home in the Cave”, by Janet Halfman. Ages 4-9Baby Bat loves his cave home and never wants to leave it. While practicing flapping his wings one night, he falls, and Pluribus Packrat rescues him. They then explore the deepest, darkest corners of the cave where they meet amazing animals—animals that don’t need eyes to see or colors to hide from enemies.
“Stella Luna”, by Janell Cannon. Ages 4+OK, this isn’t about caves and caving but it’s worth mentioning. “Stellaluna” has been charming picture-book readers for years with its moving tale of a lost little bat who learns a big lesson about friendship.
“Underground”, by Jean Farris. Ages 12+Set in Mammoth Cave in the 1800’s, this historical drama follows a slave girl as she meets Stephen Bishop (A real person from this period. He’s also a slave, and he’s a famous early explorer of Mammoth Cave). In this compelling novel, two young people explore what sorts of freedom they can find, even as slaves.
“Tales of Dirt, Danger, and Darkness”, By Paul Jay Steward. Ages 12+? (may be too scary for some children)
https://caves.org/grotto/cnjg/reading-suggestions.pdf
Picture Books about Caves:
Caves – by Kimberly Hutmacher
Caves and Caverns – by Gail Gibbons
Caves: Mysteries Beneath our Feet – by David Harrison
Caves in literature:
The Odyssey by Homer
The Faerie Queene by Edmund Spenser
Dante’s Divine Comedy
Journey to the Centre of the Earth by Jules Verne
At the Earth’s Core by Edgar Rice Burroughs
Adult Nonfiction Caves:
Into the Planet: My Life as a Cave Diver by Jill Heinerth
Mammoth Cave Curiosities: A Guide to Rockphobia, Dating, Saber-toothed Cats, and Other Subterranean Marvels by Colleen O’Connor Olson
The Boys in the Cave: Deep Inside the Impossible Rescue in Thailand by Matt Gutman
Beyond the Deep: Deadly Descent into the World's Most Treacherous Cave by William Stone
Adult Fiction Caves/subterranean civilizations featured:
Point Blank (FBI Thriller #10) by Catherine Coulter
Blind Descent (Anna Pigeon #6) by Nevada Barr
Reliquery by Preston and Child
The Descent by Jeff Long
The World Below by British science fiction author S. Fowler Wright
The Mound by H.P. Lovecraft
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