Chandelier Ballroom in Lechuguilla, one of over 100 caves in Carlsbad Caverns National Park

Seven hundred and fifty feet below the earth’s surface at a steady fifty-six degrees of temperature, the job would require I spend hours at a time.  Encountering two hundred thousand to five hundred thousand bats swirling out from a cave opening, with some of them flying within inches of my face. Crawling through an opening so small, my arms had to be above my head in order to squeeze through.  And last but not least, was this job duty not posted as a job requirement before I took the position, “When leading a tour of Spider Cave, at the bottom of the eight-foot entrance ladder you may encounter a rattlesnake or two.  Be certain to take the snake stick and bag in order to capture and relocate snake(s) so that the tour can commence.”

Those were just some of the obligations I would face as an interpretive park ranger at Carlsbad Caverns National Park (NP).

In 1995 the National Park Service (NPS) was undergoing a re-organizational effort to trim its workforce, especially in the regional offices.  It offered early retirement packages system-wide, and if vacancies were created in the parks, regional office employees would receive preference to fill those voids.  I was a concessions specialist in the Alaska Regional Office in Anchorage and decided I wanted to be back in the field.  I took a transfer to Carlsbad Caverns NP.

I had never been to Carlsbad but remembered as a kid that Carlsbad was the location of the “biggest” cave in the world.  Biggest is somewhat a misnomer when speaking of caves due to what attribute one is referring to.   If a person is referring to the cave system consisting of tunnels, chambers, entrances, connections and so forth, the “biggest or longest” goes to a cave that is also in the National Park Service, and that is Mammoth Cave in Kentucky.  Currently, Mammoth has been surveyed at over 400 miles of underground cave system, and every few years, there seems to be a discovery of a passage connecting another nearby system that expands that number.

Some refer to a “chamber” or “room” as being a cave, in, and of itself.   The “Big Room” in Carlsbad Cavern is over fourteen acres in size and up to 250 feet in height, which is humongous.  When “discovered” at the turn of the last century and officially surveyed in 1923, the distinction of containing the world’s largest cave chamber was bestowed upon Carlsbad.  Some people construed that to mean the biggest cave system totaling the area of all the rooms, tunnels, and passages.  Thus the confusion.  However, Carlsbad (specifically the Big Room) would retain the honor of the largest cave chamber up until 1981, and now it seems small compared to the current world record holder in Borneo, the Sarawak cave chamber, at just over 40 acres (however, the Miao Room cavern, a chamber beneath China’s Ziyun Getu He Chuandong National Park, is bigger in volume which just goes to complicate the matter further as to the “biggest”).

The town of Carlsbad is located in Southeastern New Mexico, “The Land of Enchantment,” with a population of around 25,000.  Surrounding the town are pecan orchards, cotton fields, cattle ranches, and the Chihuahuan Desert.  Oil fields are also present and play a big part in the economy.  Extraction of the slippery resource comes from the large underground Permian Basin, which covers a vast territory encompassing the southeastern corner of New Mexico and the southwest corner of Texas (approximately 86,000 square miles).  The Texas border is but 70 miles from Carlsbad proper, and, on any given day, the number of pick-up trucks with Texas tags equals those with New Mexico in this quiet little community.  The town embraces the national park even though the park is located upon an escarpment 27 miles distant.

When I learned my transfer had been approved in 1996, I contacted my new supervisor and asked him to forward some information about the town, schools and housing.  About a week later, I received a package from the Carlsbad Chamber of Commerce.  It contained a brochure highlighting the many attributes of the area.  I got quite a chuckle as one section proudly claimed they averaged 137 days out of the year where temperatures reached 90 degrees and higher!  Average?  Did that mean some years nearly half the calendar experienced mummifying, dry heat?  Heck, the highest temperature I faced in my nine years in Anchorage (on only one occasion) was 82 degrees.  Well it looked like I would be going from the freezer to the frying pan.

There is a lot of irrigation in Carlsbad from the Pecos River that flows through it.  Many yards have sprinkler systems, and the lawns stay green a good part of the year.  Outside of town, the landscape drastically changes to the desert environment, with prickly pear cactus being a dominant plant form.  Actually, it seemed any plant beyond the city’s borders had a little bit of green, a lot of brown and gray, and an abundance of spines of various shapes and sizes.

Many people that grew up in the area loved the desert.  It does have a considerable amount of unique features and beautiful characteristics, but it did not take this Midwestern kid long before he discovered he was not a desert person. 

I was, however, intrigued by the vegetation.  But upon my arrival, I was expecting a desert environment with the giant saguaro cactus with branches that look like arms and reminds one of Gumby.  Nope, wrong desert.  Either I had not remembered or did not know that in North America, there are four distinct deserts occupying different parts of the country.  Although there is some overlap in regards to plant and animal species, their DNA (figuratively) is separate and unique (the four deserts are Mojave, Sonoran, Chihuahuan, and Great Basin).  To see the Sonoran and the saguaro, I would have to travel hundreds of miles west towards Phoenix.  Regardless, what surprised me most about the vegetation was how drastically it could change with the simple addition of a fence. 

A big portion of Carlsbad Caverns NP is fenced off with barbed wire bordering it to separate its acreage from the vast amounts of Bureau of Land Management and private ranch holdings.  The park was first established as a National Monument in 1923, followed by National Park congressional designation in 1930.  At the time, there was already significant grazing in the area, and, by one account, a rancher had herded over a million sheep through the area.  With a legal mandate to protect both underground and above-ground resources, the park had no choice but to restrain the domesticated hoofed animals from their lands with miles of fencing.  Over time, the types of plants saved from being nibbled on, from the plants exposed to the free-range activities of cows and sheep, provided a stark contrast in the variety, height, and type of plants you’ll find on either side of the barbed barrier.

Landscape typical of Carlsbad Caverns NP.  White blooms of a yucca plant

Well, just how much nibbling is taking place, you may ask.  The vegetation looked mighty sparse, as might be expected, with annual rainfall averaging about 13 inches a year.  (But in New Mexico, they measure rain differently than here in Kansas City.  A six-inch rain in New Mexico is “you have one drop of rain here, and six inches away you’ll have another drop”)  I talked with one of the seasonal rangers who grew up and lived on a ranch and tried to impress her with my knowledge (which was extremely limited) of foraging capacity.  I had learned from a wildlife management course that in Ohio, the amount of pasture needed to support one adult cow per month (AUM – Animal Unit per Month) was between 5 and 10 acres.  I inquired about the number of acres needed to support one AUM.  I was floored when she informed me the rate for that part of New Mexico was 960 acres per head of cattle.  No wonder the ranches were (are) so darn large.

Summer Bat Flight exit from Carlsbad Cavern

I arrived the first part of July and summer was already in high gear.  I was introduced rather quickly to a mainstay of Carlsbad’s NP visitor experience, and it’s not even underground, kind of.  Attending the bat flight program is one of the fascinating natural wonders in the United States that is worth the effort. Seasonal, like the swallows of Capistrano, from early May until the cool nights of October, the temporal flying mammals seek out the dark recesses of Carlsbad Cavern and then emerge at dusk.  About 14 different bat species use the cave, with the greatest number being the Brazilian Free-Tailed Bat.  The bat cave (an area within the main tourist cavern) is used by females to deliver their young, and the area is described as a roost colony.  Between 200,000 and half a million bats will take up residence, and the concentration of such numbers provided a source of revenue to early explorers.  Bat Guano.  From 1903 to about 1923, an estimated 100,000 tons of the nutrient-rich fertilizer was mined from the cave and shipped off to the citrus orchards in California.

NPS photo – Early visitors actually started their tours using guano buckets as their transport into the depths.

Nowadays, the miners are replaced by tourists as they fill the 800 seat amphitheater to watch the multitude of bats leave the cave.  Six weeks is the general timetable for the baby bats born in mid to late May to have grown large enough and strong enough to join the nightly exit.  Therefore if you can plan on arriving after the first of July, the number of mammals of the order of Chiroperta (ancient Greek meaning hand wing) will nearly double as the young join their mothers. As an interpretive park ranger conducting the bat flight program at the edge of darkness, there are several challenges.  For one, the bats are, of course, wild, and their flight from the cave is on their own timetable.  A regular practice was to start the program 30 minutes prior to their exit the night before.  Visitors would often ask, “when will the bats come out?”  The safe answer is to say “around dark.”  That response might then prompt another question, especially from the visitors that had done the self-guided cave tour and learned they roost in the pitch blackness of their sleeping quarters.  “If the bats are in total darkness, how do they know when it gets dark outside?” (there are various theories to support plausible answers, so I would base my response on who my audience was)  Another challenge for the rangers is that to face the audience, your topic (bats) is at your back, and they may exit the cave 10 minutes into your spiel, or if you are lucky, as you are providing a riveting conclusion.  Fortunately for me, I never ran into the occasion where darkness set in and my resource had not shown up yet.

The Bat Flight Amphitheater was constructed in 1963 (mouth of the cave is to the right)

My most stressful bat flight was my very first one.  I had been at the park for about three weeks, shadowing other rangers and reading a lot of material ranging from human and cultural history to the various resources pertaining to the geology, fauna, and flora of the area.  I had led a 90 minute Kings Palace guided tour below ground and an above-ground hike at nearby Rattlesnake Springs.  It was late July and in the midst of monsoon season.  The “monsoons” of the southwest are basically pop-up thunderstorms that appear in the afternoon, often with little notice, and are brief but sometimes turbulent rain events.  As darkness approached and with an audience of around 600 persons sitting at the entrance to the cave, I heard a rumbling in the crowd and people pointing over my shoulder.  The wind was picking up, and clouds were moving in.  I was but a few minutes into the program and was hoping that the audience’s attention was not on a flurry of bats.  I looked behind me and above the cavern entrance were a couple of browsing mule deer.  I was relieved.  They are cute, but their presence was not out of the ordinary, and I informed the crowd of what species of deer they were looking at. I exhaled and continued on.  Not long afterward, a woman cries out, “Is that a tornado?”  Obviously, something I could not ignore, as I was the mighty park ranger, protector of people, places, and animals! (Ha!) I swirled around to see a dust devil twirling away about a half-mile distant.  Another crisis diverted as I anxiously hoped for a rapid appearance on the part of the bats.  But, the trifecta was not complete.  A short time later, within the crowd, about three-fourths up the bowl-shaped amphitheater, people began parting like Moses and the Red Sea.  The shrieks were not many, nor too loud (thankfully!). Down from the top of the seating area, a law enforcement ranger came to the rescue and took care of the situation.  I would not learn until the program ended and the crowd thinned out that a tarantula had made an appearance and was strolling through the masses.  Finally, the bats showed up, and the group was thrilled, not to mention me.

Other bat flight programs were exciting, as exciting as nature can be at times.  A rattlesnake and squirrel playing cat and mouse on the stone wall alongside the path into the cave, bats flying low over the audience (never landing in anyone’s hair, but a few people got bombed with guano), a centipede recreating the scene of the tarantula.  These were just some of the great experiences witnessed by the tourists and me, and the best part was, the entertainment was free.  Which, by the way, is my favorite four-letter word which contributes to my wife’s notion that I am cheap (when she mentions it, I reply no, I’m thrifty!).

Entering the cave, however, is likely to cost you, with some exceptions. If you are a child age 15 or younger, the entrance fees do not apply.  If you are a fourth grader and possess the Every Kid Outdoors pass, the pass grants free entry for fourth graders, all children under 16 in the group, and up to three accompanying adults (or an entire car for drive-in parks) to most federally managed lands and waters.  Also, holders of other “America the Beautiful” passes are probably exempt from the fee.

Half the challenge of visiting Carlsbad Caverns NP is its location.  The wide-open west is not just a saying but also a descriptor of the distances involved.  For instance, if flying to the southwest to a major airport closest to Carlsbad Caverns, you would be landing in El Paso, Texas.  Driving from there, you take US route 62/180 headed east.  Make certain you have a full tank of gas because once you leave the outskirts of town, the next gas station is about 100 miles away.  If a flight is taken to Albuquerque, the distance is further than El Paso; a five-hour drive confronts the tourist upon touchdown. 

Once you reach the park, one can catch the highlights in short order.  The quickest option is to do the self-guided “Big Room” tour.  A one-minute ride down the elevator 750 feet takes you to the edge of the historic underground lunchroom.  For the early pre-elevator visitors, all the tours were guided, and you walked in through the cave opening, down the natural entrance trail, around the Big Room, and back out the way you came in, a round-trip distance of around four miles.  The journey would take between 6 to 8 hours; thus, refreshments were needed along the way.  The lunchroom was constructed to satisfy the hungry visitors.

Many past visitors would share their fond memories with me of eating in the lunchroom long ago.  To the observant visitor, one can still see the blackened grease stains on the rock ceiling behind and above the food counters where chicken sizzled and such fried fare was on the menu.  Such practices and menu items were banned long before I arrived, and now the only cooking that occurs is in microwave ovens. The dining experience would not have been a highlight of mine, but it would be a unique experience (there is a full-service restaurant within the visitor center just 60 seconds up the elevator).

Immediately leaving the lunchroom and elevator lobby area, the cave opens up, and you realize that Carlsbad is no ordinary cave. 

Carlsbad is so vastly different than what I had experienced as a kid.  Growing up in Ohio, my elementary school took a field trip to Ohio Caverns near Dayton, Ohio. I still remember its most famous feature, the Crystal King, a white stalactite that was the biggest in the Buckeye state.  Aside from that, I remember the passages were narrow, the air was cool, and it was wet with active formations. 

In middle school, as part of a church youth group outing, we went to Olentangy Indian Caverns. That cavern was special because it was within our school district (no surprise that I went to Olentangy High School), and several classmates found seasonal work at the caverns.  It, too, was cool and damp, but far fewer formations than Ohio Caverns.  The caverns and school were both in Delaware County, which was predominately farmland.  Yes, the county has the town of Delaware, home of one of Ohio’s eight presidents, Rutherford B. Hayes, but the open landscapes beyond the city limits provided many opportunities for exploring.  My brother and I learned while traipsing through neighboring farmer’s fields looking for arrowheads that, on occasion, there would be a clump of trees right in the middle of a field for no apparent reason.  Upon further inspection, we discovered that such clumps were sometimes an indicator of a sink-hole which provided an opening into layers of cave forming limestone bedrock.  Wise farmers became wary of such adventurous youth and would often try to fill the voids with empty barrels or old fencing and other debris, to try and keep the curious from getting in over their heads.

We were not the only ones seeking such adventures, and a number of fellow students had found actual passages and small cavern systems in the karst rich region near our homes.  Spelunking (the official caving term), or caving as many would say, became quite the thing, and stories of apparent first discoveries ran rampant throughout the hallways. One of those “discoveries” was within a half-mile of the Olentangy Indian Caverns boundary.

I learned of that cave from my older brother, who had checked it out.  I shared the information with Bill, a classmate, and asked him if he would like to explore the cave with me.  He was up to the task.  We did minimal planning and decided to check it out immediately after school the next week.

The cave started out as a crack in a dry creek bed in a wooded area.  The opening was about 18 inches wide, and the sliver was about 6 feet in length.  I noticed it was a little cloudy and about 70 degrees on the surface as we negotiated the crevice.  It was tight at first and opened up a bit as it dropped about eight feet down to a moist tunnel.  On the floor, I noticed some footprints, which made sense because my brother and a friend had been there just a week before. I also noticed some raccoon tracks and wondered if the raccoon was still down in the cave.  I wondered, too, if maybe the raccoon did not want us down there.  What if the raccoon had rabies, I thought?  Obviously, either Bill didn’t notice or didn’t care to notice as Bill dropped to his knees and started to venture into the darkness.  He realized quickly he needed light and was able to turn around while on his hands and knees to reach out to have me light his candle.  Each one of us had a candle as our only source of light, a candle we held in one hand as we started to crawl through the passage.  Bill must have been excited, and soon he was out of sight.  I tried to pick up my pace but was being careful not to extinguish my candle. I called out, telling Bill to slow down, to which there was no response. On a few occasions, I hit my head on the ceiling, and I was thinking wearing a pair of knee pads and elbow pads would have been beneficial.  It was cool and damp, and soon my jeans would be of like condition.  I thought occurred to me, as I could no longer hear Bill rustling ahead of me.  What if there were a proverbial fork in the road and Bill went one direction and me the other.  I yelled my concern to Bill, not knowing if he heard me.  Again, I increased my effort trying to catch up to him.  A minute or two passed by, and still no sight of Bill. 

I then thought about the weather outside and if a rainstorm might develop.  It didn’t take me long to realize we would not be in a pleasant location in the water cycle if the rain were to come down, pour into the streambed, drain into the crack and funnel into the tunnel of which we were crawling.  The size of the passage at that point nearly required us to slither on our bellies.  I suspected we could be in deep trouble.

Hindsight, of course, is 20-20.  Teenagers do some crazy things, and planning is not necessarily a strong point.  We were off on an adventure, feeling like we might discover uncharted territory.  We did not know of the caver’s rules of three.  One; travel in a group of three in case a member gets hurt.  One person can tend to the wounded while the other goes for help. Rule two, tell at least three persons on the surface where you are going and when to expect you back.  No one knew of our whereabouts, and we both figured we would be home by dinnertime, so why bother?  Plus, I thought if I told my folks, they might put a kibosh on our expedition.  And last but not least, carry with you three sources of light.  Three reliable sources and an extra set of batteries if required.  Candles, I have learned, should be the last resort.

I continued my advance with no sign of Bill.  Bill must have felt he was leading us to undiscovered chambers or bags of gold deposited by train robbers from a long, gone era. After a bit, I heard a muffled cry, “Oakes, my candle went out!”  The thought that hit me was, “Karma has struck!”  I began to laugh a little bit under my breath as I realized (as did Bill) that I had the only pack of matches.

I yelled to Bill, telling him to wait where he was and that I would find him.  Still, he did not listen.  In his dubious position, the fear from being in pitch black conditions, in cold, damp, tight quarters caused him a great deal of anxiety which could be heard in his curses and cries for help.  Somehow, he managed to change directions and made his way back towards me.  And luckily, the matchbook in my moistened pocket had not soaked clear through and was not needed as I shared the flame from my candle to reignite his. 

I never went caving with Bill again.

Postscript:  I returned to the scene of our adventure, or misadventure may be a better word, several weeks later equipped with a 9-volt lantern, elbow and knee pads, warmer clothing, and a different partner, Eddie.  We were able to go much further, with Eddie in the lead.  The tunnel was more difficult to navigate, which slowed our progress.  Eddie, too, got ahead of me, and the cry I heard from him was of excitement as he entered a chamber that was about 20 feet high and ten feet wide.  Soon after, I joined him.  At first, we thought we had hit the mother lode, virgin territory, but quickly discovered modern etchings on the walls, names of classmates, and dates of their visit.  We pushed no further, and it was starting to get late.  Our non-discovery was a little disappointing, but overall a fun time.

Little did I know that 20 years later, I would be caving once again, but in a different state and observing the cavers rule of three. Outside the elevator lobby of Carlsbad Caverns, one turns left onto a low and narrow pathway.  On more than one occasion, when I passed through, I would scrape the ceiling due to my six-foot height plus three inches of ranger hat as I lead a group towards the King’s Palace guided tour.  Often when my group went through the short passageway, gasps would occur from those first seeing the Big Room.  The Big Room is like an indoor concert hall with a high ceiling and filled with an amazing number and types of formations of formidable size.  Interestingly the volume of North America’s largest cave chamber is not unusual for caves in the region.  A common characteristic of caves of the Guadalupe Mountains area (over 400 caves, including Carlsbad) is that they have rather large chambers.  How the caves were formed is what sets them apart from Mammoth Cave and most other cave systems. Most cave systems are believed to have formed in part from the erosive force of moving water underground, which followed the cracks in the limestone, dolomite, or gypsum bedrock and between successive layers of rock.  This resulted in long linear passageways, and the different levels of catacombs were indicative of fluctuating water table levels. The slightly acidic nature of precipitation percolating down through soil and rocks also played a part, especially in producing speleothems, that is, stalagmites and stalactites, and other cave formations. In the region around Carlsbad, it was with fairly simple observations and deductions that University of New Mexico geology student Carol Hill came up with a different theory of how underground cavities could be formed. 

Barely noticeable in this gypsum block, is evidence that water dripped on this massive chunk, dissolving the gypsum and creating tube like holes.

Ms. Hill noticed the huge blocks of gypsum in Carlsbad Cavern and discovered there weren’t any good explanations on how they got there.  Also, she became acutely aware of the oil extraction activity in the area and that the vast reserve of petroleum and natural gas came from the Permian Basin hundreds and thousands of feet below the earth’s surface.  She realized gases from these reserves do find cracks in the overlying rocks and seep upwards.  The gases contain a significant amount of hydrogen sulfide, which, when it comes in contact with water, becomes sulfuric acid.  Sulfuric acid is the most corrosive of the acids, and when it is in the presence of calcium carbonate, the main mineral of limestone, the acid will dissolve the limestone through a chemical process, and a by-product of that reaction is the formation of gypsum.  (Gypsum also is the reason why White Sands National Park exists.  Located north of El Paso by Las Cruces, New Mexico, it contains the largest gypsum sand dunes in the world!)

It took years before Hill’s theory, presented in the late 1960s, was accepted by the scientific community.

Caves are scientific marvels, and there is still much to be learned of their underworld environment.  Like looking out at the universe and wondering when the next great comet will arrive or trying to determine how long it will be before our sun evolves into an earth-consuming red giant, noticeable changes in caves typically occur over a long period of time.  I was fortunate to have been at Carlsbad when something did change and in a relatively short period of time.  I was told the area was suffering a drought and what I saw of the vegetation was evidence of that fact.  In the cave, there was further proof, as many of the pools were either dried up or severely lowered from the lack of rain. The summer following my arrival, Carlsbad received one and one half its normal precipitation, close to 20 inches for the year.  On the surface, the desert did come alive, and although I did not notice plants flowering overnight from a significant spring rain shower, the desert was more green and more flowered a week after the precipitation.  However, I expected more of a flourish as the rains came often.  Not a lot of rain, but the frequency was enough that the locals commented on the apparent abundance.  But in August, the park’s fire management officer (who specialized in weather) informed me, “It doesn’t get any greener than this.”  He must have seen the disappointment on my face.

Each rainfall will have a unique chemical signature based on the proportion and types of radioisotopes within the precipitation.  Using this information, scientists have been able to calculate the elapsed time it takes for water to percolate through the soil and rock.  For Carlsbad Cavern’s Big Room, it takes anywhere from as little as three weeks to 18 months for the liquid journey of 750 feet.  I had the distinct advantage of witnessing a transformation. 

One of the chores as a park ranger is the “sweeping” duties at the end of the day. At a predetermined time, visitors are no longer allowed into the cave.  And to make sure no one decides to spend the night, a ranger will follow the last group collecting any stragglers and then turning off the lights in the closed section behind them.  At times this would be a lonely job when the final group left 30 minutes before the sweep started, and they had a formidable head start in time and distance.  I saw this as an opportunity for quiet and solitude.  So quiet that you could hear the infrequent drips along the trail.

“Normal” pool levels for Longfellows Bathtub

During the summer of rains, I noticed the dripping had intensified, and as a result, the pools began to fill.  Some of the formations became active; that is, calcium-laden water droplets would make the formation wet and, on a microscopic level, leave a deposit of the mineral.  A frequent question the rangers would get was, “How old are the stalagmites?” (or stalactites). These formations can be dated by doing a core sample and in the case of one 23 foot high stalagmite that was sampled in the cavern, the “Texas Toothpick” was determined to be at least 560,000 years old.  So, to see the water level in Longfellow’s Bathtub rise about four feet to the rim in a matter of weeks was truly impressive to me.  Unfortunately for most visitors, their visit is likely a snapshot in time with no prior knowledge of what the pool levels were prior to the increase in precipitation.

The Christmas Tree formation in Slaughter Canyon Cave fell victim to the wet conditions as well.  When dry, crystals on the exterior surface will reflect the light from headlamps producing a sparkling glow.  But not when wet.  Slaughter Canyon Cave is about 15 miles from Carlsbad Cavern and accessed as part of the ranger guided tours for an additional fee.

Off the underground lunchroom is an area known as Left Hand Tunnel.  In it, a remarkable discovery was made in one of the pools.  A bacteria was found that was producing its own food by not digesting any substances of carbon but by eating the iron within the rock.  The process is known as chemoautotrophic, whereas the organism derives energy from the oxidation of inorganic compounds.  There is speculation that this process was involved in carving out the caves themselves, given the geologic timetable of cavern formation.  A more exciting prospect, however, is that some of these unique bacteria produce bioactive compounds with anti-cancer properties.  One study indicated an isolated compound was effective in destroying lung cancer cells while leaving the normal, healthy tissue alone.  More research is needed, and little disturbed cave environments are being explored worldwide to see what other beneficial biota can be found.

Stability is one way to describe the environmental niche of caverns.  With the nearly constant temperature and humidity, in many ways, it is an ideal, protective space.  So protective that at the height of the atomic bomb scare in the 1960s, a plan was devised, and supplies were stored in Carlsbad Caverns to serve as an emergency fallout shelter.  The Civil Defense Corps later abandoned the plan when scientists revealed air exchange within the thirty miles of known passages, chambers, and cracks (with no practical way to seal the cave) occurred every 30 hours, thereby rendering any protection from airborne radioactive fallout, fruitless.

The fact that caves “breath” is not so unusual, especially when a cave has limited openings and a significant volume of space underground.  Apparently, some caves have been discovered during the wintertime when a high-pressure system intrudes upon the landscape for a day or two, followed by a weather system of low pressure and frosty temperatures.  As a result, the high pressure that built up in the cave will flow towards the lower pressure area (the outside atmosphere); therefore, the relatively warm moist air of the cavern will be expelled from the opening producing a plume of “smoke” much like when a person fogs up the air in front of their face by exhaling deeply on a cold morning. (Similarly, “Lechuguilla Cave” was discovered this way)

Side note: Sundown will produce a small dip in atmospheric pressure. Scientists speculate the pressure drop is the trigger that tells bats nightfall is approaching and it is time to leave the cave.

Likewise, the humidity will often fluctuate inside a cave, and Carlsbad is no exception. For Carlsbad, the humidity inside drops during the winter months.  From about 93.7 percent to 93.2 percent in Lower Cave. Such a minuscule amount would seem negligible to insignificant in most situations, but in Carlsbad, a magical thing occurs in that section of cavern known as Lower Cave.    Early in my tenure, I was the trail ranger alongside my partner Danny, who was legally blind (but an excellent tour guide).  We were in Lower Cave when he pointed out a small fuzzy patch along the floor of the passageway.  The patch was actually wispy, white, delicate strands, and Danny told us not to get too close, as even a waft of air current might break the slivers of crystals.  The mineral was called epsomite.

An example of epsomite, but not the specimen I saw in Lower Cave.

Lower Cave is one of the ranger guided off-trail tour options and in my opinion, one of the best.  If time allows you to do just one, off-trail tour, I recommend Lower Cave.

 It has the same chemical composition as what most folks know as Epsom salts.  We saw it in the crystalline form, and it appeared as an encrustation where the floor of the cave met the wall.  I did not realize how rare it was until I shadowed another ranger on the same tour during the summer.  When we got to where I saw the epsomite during the winter, all I saw was a white patch on the floor where the hairy patch of crystals was before.  I learned that due to the one-half percent increase of humidity in the cave (as happened every summer), the solid form of the mineral had dissolved and would not return until the humidity dropped, oh so slightly.

Panoramic shot of the Big Room
The Lion’s Tail provides a good look at how cave popcorn will attach itself.  The popcorn can be seen adorning the wall in the background as well.

It does not take one long to appreciate the enormity of the Big Room.  The hand-railed enclosed 1.25-mile paved trail around the Big Room provides a great sampling of what you need to see and for one to say, “I did Carlsbad Caverns.”  Cave popcorn adorns every wall and many of the formations.  Stalactites, columns, and stalagmites abound. 

Caveman on the left and the Totem Pole on the right

The human-placed names actually resemble what they are called, like the Caveman.  And the bottomless pit, of course, suggests it goes all the way down to China (the floor of the pit cannot be seen from the trail, 14 stories below).  There are hidden gems galore, some of which I was still learning after three years on the job, like the survey mark indicating where the one time proposed tunnel would emerge from the caves’ wall allowing cars to drive through the caverns, or the ancient bat, encased in deposited calcium. 

In the Hall of Giants, one walks among the massive speleothems, or get up close and personal with the Twin Domes.
Carlsbad history tells us a Hollywood movie production company laid out the lighting to accent the many features, often with dramatic effect.  Above is the “Chandelier” in the Big Room.

The National Geographic Society has had a keen interest in Carlsbad for over a hundred years and was a sponsor of an expedition to map and survey the cave in 1923.  A roped ladder is still in place and can be seen along the Big Room route.

Rock of Ages

Although lacking eyeless cave shrimp, unpigmented crayfish, and cave salamanders (due to the lack of underground streams), there are life forms that spend their entire life in the darkness, such as cave crickets.

A better way to experience Carlsbad Caverns is from the perspective of the early explorers.  Entering the cave from the Natural Entrance provides an awe-inspiring journey.  The one-mile trek descends 750 feet on a paved trail.  Along the route, the gradient is quite steep, up to 21 percent; therefore, the path is not for everybody, and those with bad knees, back or heart, might reconsider doing the Natural Entrance option.

The wide opening provides significant light for about the first 30 percent of the route.  For a significant part of the year, cave swallows can be seen darting in and out of the cave.  Some visitors mistake these avian critters for the bats; I jokingly referred to the swallows as the “day crew” doing their part to harvest the flying insects.  Of course, the “night crew” consisted of the famous Brazilian Free-Tailed bats. “But how can you tell” a visitor might query.  Well, aside from the obvious, birds are flying during the day, bats at night, the motion of a bat’s wings in flight is constant, but birds will often glide a short distance and have a break in their wingbeat. 

As the trail dives down into the depths, a glimpse over your shoulder confirms you are entering an environment that is not too common to humans, and one can easily recognize the excitement that early explorer Jim White felt, making his way down.

Further along, the path doubles back going underneath the entrance hole and providing a great view of where you came from.
On a limited number of days in the year from the same vantage point as in the previous photo, the angle of sunlight produces this stunning sight!

Jim White was a young cowboy when he started his caving.  He is credited for “discovering” Carlsbad Caverns. His impression of Carlsbad may have left an ominous impression based on several of the areas he named, such as the Devil’s Spring, the Witch’s Finger, and the Devils’ Den.  Just where do you think Jim White thought he was headed?

The Devil’s Spring and the Witch’s Finger, respectfully

A multitude of different formations are prolific in the Queen’s Chamber.

Some have suggested that as Jim got more comfortable with his repeated ventures into the abyss and uncovered more decorated areas, that his attitude changed, and so did the nature of his proclamations, such as the “Kings Palace” and the “Queen’s Chamber.”  Both of these highly decorated areas were part of the route down when all the tours were conducted by rangers.  In the 1960s, the main routes were open to self-guided excursions, but vandalism in the secluded and beautiful King’s Palace and Queen’s Chamber forced the park service to make these areas available only as a separate, ranger-guided tour limited to 75 persons.

The 90-minute King’s Palace (pictured above) tour includes visiting the Queen’s Chamber

The Natural Entrance trail connects to the Big Room one mile from the Bat Flight Amphitheater.  For most visitors, the trip takes about an hour but, because it is self-guided, one travels at their own pace.  Electronic audio guides are available to rent from the Western National Parks Association store in the visitor center.  The fascinating narrative covers both the Natural Entrance and Big Room routes.

In a relatively short period of time, a visitor can see the not-so-ordinary basics of Carlsbad Caverns National Park.  During the summer, viewing the nightly Bat Flight program is highly recommended.  Families (and, of course, other tourists) that arrive in the Carlsbad area in the afternoon can plan on attending the Bat Flight that evening, then come back the next day and just do the Big Room in less than two hours, or the combination Natural Entrance/Big Room route of three hours or more.  Or if one arrives early in the day, one can easily do the two self-guided routes in the cave before it closes, then stick around for the Bat Flight at night (sunset on July 1 is 8:08 pm) for a “Been there, done that” approach.

For those with more time and the financial resources to expend, there are a myriad of ranger-guided tours available.  The popular King’s Palace tour starts from the Underground Lunchroom area and lasts about an hour and a half.  For the adventuresome person who wants to get off the beaten (and paved) path, the off-trail tours vary from a lantern-lit trip into Left Hand Tunnel to the shimmy on your hands, knees, and possibly belly tours.  These require a little climbing and crawling, and use of a helmet (if needed, it is provided by the park and included in the tour fee) and headlamp is necessitated. 

The entrance to Spider Cave (left) requires climbing down a ladder about eight feet.  The cave got its name from the usual collection of Daddy Longlegs (or Harvestman) spiders that like to congregate within the first 10 to 15 feet of the cave.  More of a concern to the lead ranger is the possibility of rattlesnakes at the base of the ladder.  Immediately after dropping down to the floor of the cave, it is a tight crawl (bottom photo) for about 20 feet.  I recommend elbow and knee pads for this off-trail tour.

The National Park Service is mandated “to conserve the scenery and the natural and historic objects and the wildlife therein and to provide for the enjoyment of the same in such manner and by such means, as will leave them unimpaired for the enjoyment of future generations.”   (The quoted verbiage is from the NPS organic act of 1916). One very special resource within the boundaries of Carlsbad NP is likely best protected by limiting its explorations by the masses to a virtual one.  Lechuguilla Cave is the second deepest limestone cave in the United States and one of the ten longest caves in the world (over 145 miles).  From the park’s website is a great description of what Lechuguilla contains,  “A fantastic array of rare speleothems, some of which had never been seen anywhere in the world, includes 20-foot (6 m) gypsum chandeliers, 20-foot (6 m) gypsum hairs, and beards, 18-foot (5.5 m) soda straws, hydromagnesite balloons, cave pearls, subaqueous helictites, rusticles, u-loops, and j-loops.”

Pictured below are some of the phenomenal sights rarely seen in person due to the nature of the cave and the restrictions in place.   For more on Lechuguilla Cave, visit the park’s website.

“Big Sky” chamber
Cave Lily Pads
Pristine cave pool
Lengthy soda straw formations
Gypsum chandelier
Delicate Helictite
Wizard’s Staff
The great comet of 1997, Hale-Bopp

Side Note: Co-discoverer Alan Hale came across the comet while observing the night-time sky in his driveway at his Cloudcroft, New Mexico home, elevation 8,676 ft.

Carlsbad is becoming known for another great resource, and it is not underground.  Dark Skies.  As a kid growing up during the space race, I developed an interest in astronomy.  In reading the popular astronomical literature, it did not take me long to figure out that some of the darkest skies in the country were in the sparsely populated regions of the southwest. My transfer through the park service to Carlsbad and the discovery of Comet Hale-Bopp created a perfect storm of opportunity for Carlsbad Caverns NP to capitalize on its good fortune.  As an interpretive park ranger (giving the talks and tours), I recognized a way to provide additional interpretive programming and entertainment for the visitors.  Soliciting help from local amateur astronomers with telescopes, we tried conducting “star parties” on the veranda in front of the visitor center.  My fellow rangers allowed me to announce the star party program at the beginning of the Bat Flight program.  With a built-in audience just a couple hundred yards in the amphitheater and fabulous dark skies, dozens, if not hundreds of people would join us for our informal astronomy presentation after the Bat Flight.   In addition, we conducted several Comet Hale-Bopp programs at the caverns and several locations near town.  They were resounding successes, often breaking attendance records.

I pitched my idea of a more permanent programming arrangement and the parks’ acquisition of a telescope to the Chief of Interpretation.  He was skeptical because I was the only one on staff with decent astronomical knowledge, and if I left, he wondered who would do the astronomy programs.  I informed him that I knew very little about bats before I came to Carlsbad, and I learned enough to do Bat Flight programs, so logically the same could be true for other rangers in researching what was needed to do astronomy programs.  He got my point, and now there are regular night sky observing programs using a telescope the park purchased.

Carlsbad Caverns National Park and the surrounding area is rich in natural, cultural, and historic resources.  Easily one could spend several days or more in the area.  There are 18 sites administered by the National Park Service in New Mexico alone, not to mention Guadalupe National Park (the highest point in Texas is Guadalupe Peak at 8,749 ft and lies within Guadalupe NP), which shares a border with Carlsbad but lies within the state of Texas.  Here is a listing of all the sites.

Who knows, upon visiting Carlsbad NP, you just might run into someone you know.

For more information about Carlsbad Caverns and caves, check out these items from KCKPL.

For Kids

Carlsbad Caverns by Robin Koontz

Travel Adventures: Carlsbad Caverns Identifying Arithmetic Patterns by Dona Herweck Rice (en español tambien) “Aventuras De Viaje Carlsbad Caverns” – Hoopla E-book

Biggest, Baddest Book of Caves by Alex Kuskowski

World Below” by Wesley King –fiction

And adult fiction

Blind Descent an Anna Pigeon novel by Nevada Barr*  (Ms. Barr was a seasonal ranger at Carlsbad Caverns and based several of her characters on co-workers of mine)


Carlsbad and Carlsbad Caverns by Donna Blake Birchell

Arizona and New Mexico: 25 Scenic Side Trips by Rick Quinn

Carlsbad Caverns National Park website

Photo credits:

  1. NPS – Max Wisshak
  2. NPS
  3. NPS  – Nich Hristov
  4. NPS
  5. NPS
  6. NPS
  7. NPS – Peter Jones
  8. NPS – Peter Jones
  9. NPS
  10. NPS
  11. NPS
  12. NPS – Peter Jones
  13. NPS – Peter Jones
  14. NPS – Peter Jones
  15. NPS – Peter Jones
  16. NPS – Peter Jones
  17. NPS
  18. NPS – Peter Jones
  19. USGS – Alex Demas
  20. NPS
  21. NPS – Peter Jones
  22. NPS – Tom Boles
  23. NPS – Peter Jones
  24. NPS – Peter Jones
  25. NPS – Peter Jones
  26. NPS – Peter Jones
  27. NPS – Peter Jones
  28. NPS – Peter Jones
  29. NPS – Jean Krejca
  30. NPS – Daniel Challoux and Peter Bosted
  31. NPS – Gavin Newman
  32. NPS – Shawn Thomas
  33. NPS – Gavin Newman
  34. NPS – Shawn Thomas
  35. NPS – Aaron Stockton
  36. From Steve Oakes collection
  37. NPS
  38. White House Photo – Pete Souza

About the author:  Main Library Associate Steve Oakes was an interpretive park ranger at Carlsbad Caverns National Park from 1996 to 1999.  Oakes will be presenting an interpretive program on Carlsbad Caverns NP at the Main KCK library in 2021.  It is tentatively slated for the month of August.

© Steve Oakes