Costa RicaCosta Rica

Day 6: Spelunking in Venado Caverns

Destination: Arenal

a perfect spot for morning coffee at montana de fuegoI was excited, if a little nervous, to visit the Venado Caverns today. The idea of ancient, wet rocks and sleeping bats intrigued me, but I wondered if I would feel claustrophobic. Several people had warned me that a sudden fear could envelop me; in fact, Noelia, who had been one of my guides to Rio Celeste, had told me that she can't explore the caverns because of sudden-onset claustrophobia. I didn't believe it would happen to me, but I was prepared for the possibility.

Alfredo, one of the Desafio guides who accompanied me to Rio Celeste, picked me up at 7:15 a.m. sharp. We headed east out of La Fortuna, following the same route we had taken to the celestial river just days before. The Venado Caverns are much closer however, and we pulled in to the cave entrance a scant 45 minutes later. During the drive, my excitement had mounted, and I was more than ready to go spelunking.

entrance to venado caves

Our first matter of business was suiting up. Instead of donning the rubber boots offered me, I laced up my water-resistant hiking boots. I did, however, accept a hardhat, dust mask (to protect against guano fumes) and flashlight, and soon looked like a true cave explorer. I covered my camera backpack in a large plastic bag -- water drips from the cave ceilings, and we would be walking through an ankle-deep river all morning -- and strapped the camera around my neck. I was ready to go.

Alfredo and I buddied up with a family from West Virginia and one of Venado's own guides. Together, the six of us walked down the grassy hill that leads into the caves, while discussing what we would see today. Though the caverns were only discovered by hunters in 1942, they began forming some 15-20 million years ago. The caverns as a whole are over five million years old. Stalactites and stalagmites, the conical deposits that hang from cave ceilings and grow up from the floor, are the products of dripping water, which leaves behind tiny calcium carbonate deposits. Incredibly, it can take 100 years to form just 1.5 inches worth of rock formation.

calcium carbonate cave walls

Approximately half of the caverns are accessible to the public; the inaccessible half is not dangerous, but rather made up of very narrow, and hard-to-navigate tunnels not suitable for beginning spelunkers. Today, we would visit three main rooms -- The Baths (Los Banos), The Altar (El Altar) and The Papaya (La Papaya) -- each named after descriptive physical features and rock formations. Alfredo told me that there would also be a few adventurous options, and that I would have the choice of skipping or exploring.

We entered the caves at a large, mossy entrance. A small stream flowed out from inside the caves. We walked in just a few steps and began to adjust our eyes to the darkness. Small rocks littered the stream bed, and I took each step with ginger care. Soon, we were deep enough into the caves that no outside light filtered in, and our faint flashlights did little to illuminate the path. I've always heard that when one sense is dulled or incapacitated, others become stronger; I cannot say whether my hearing was compensating for my lack of sight, or if I was just paying closer attention, but my ears were suddenly attuned to everything.

Water dripped down the cavern walls. Our feet splashed through the burbling stream. Wings flapped above our heads. Wait, wings? That's right. Glancing up, I saw that bats covered the ceiling. Most were merely dangling upside down, but some were flying around haphazardly, surely disturbed by our loud voices, odd scent, and bright flashlights. There are four main bat species that dwell in the Venado Caves: the insectivorous sword-nosed and mustached bats, the nectar-loving Pallas' long-tongued bat, and the little-studied greater naked-baked bat. Unfortunately, there was too little light and too much space between me and the small mammals to tell which species was roosting above my head, but I can tell you that it was an incredible sight and sound to behold.

swooping bats (�� fausto augosto perez)

At the same time as we gawked in amazement at the bats above us, we noticed that there were large holes in the ceiling. Each looked to be almost a foot in diameter, with perfectly smoothed edges. It was hard to tell how deep they reached, though I could make out that some were barely formed, just small, curved indentations in the ceiling. Alfredo explained that these are small bat shelters, where the mammals can huddle together for warmth during storms or cold conditions. They create the holes by depositing excrement and urine onto the ceiling, utilizing the fluids' corrosive power in conjunction with their nails to slowly chip away at the cavern walls. Thought it is difficult to determine, cave experts believe that the deepest holes can take approximately 20 years to create.

We continued on, and soon arrived at the first room, called The Baths. Here, a sheet of falling water divided the cavern into two dry spots. We passed under, enjoying the cool sensation of water dripping down our sweaty backs. On the other side, Alfredo pointed out small seashells embedded in the cave walls. Scientists believe that the caves were underwater for many millions of years, only drying out after tectonic plates shifted their position. Today, the caves rest at approximately 985 feet above sea level.

"el parto," or "the birth" tunnel

After we had finished playing in The Baths, we doubled back and continued on toward The Altar room. Before we had arrived, our Venado guide stopped and indicated a nondescript tunnel to our left. Designated "The Birth" (El Parto), this narrow tunnel is one of the more adventurous sections of the caverns. It disconcertingly resembles the birth canal, and to pass through it, one must stretch out, wiggle and pray to make it through safely. On the other side, there is a 22-foot vertical climb, which can only be achieved by standing on the guide's shoulders. Though I'm usually the most adventurous in the group, I didn't quite feel comfortable, and passed. Two members of our group decided to take the plunge, and we watched them slip through the tiny hole, laughing and screaming as they climbed up the other side. Before long, they had rejoined the group, and we soldiered onward.

To reach The Altar room, we maneuvered through very tight, low spaces. My camera backpack was cumbersome, and often got stuck on rocks. Alfredo kindly went ahead of me, taking the backpack with him. As I squeezed through the tunnels, sometimes crawling on my stomach, my hardhat cracked against the stony surface... about twenty times. (I was so glad to have protection for my head.) On the other side, we were advised to pull our dust masks on; here, the smell of bat guano, or feces, was very strong, and it was important to protect our lungs from the fumes.

papaya formation at venado caverns

The Altar was an amazing sight, and by far my favorite of the day. Calcium carbonate formations rose up from the floor, forming a perfect stairway. Though the rock appeared to be smooth, it was not slippery, and for the first time today, I walked with confidence. At the top of the natural altar sat a gigantic brain coral, at least five feet in diameter. Scientists believe that it is a fossilized brain coral several million years old, another remnant from when the caverns were under the sea.

Our last stop was in The Papaya room, where a gigantic stalactite-stalagmite formation joined to create the perfect likeness of a papaya. The "fruit" has been carbon-dated to approximately 6 million years old, a staggering age that my mind could only roughly comprehend. Interestingly, the papaya formation can grow no larger -- instead of being composed of pure calcium carbonate, it has clay mixed in. Since the clay is no longer present in the caves, and calcium carbonate alone cannot stick to its surface, the only change that the papaya will see is slow erosion over the years.

dripping water in venado caves

On the way out of The Papaya room, we were invited down another narrow tunnel. Though this one tempted me, I again chose the easy route -- carrying a camera into the caverns makes for good photos, but is not a wise accessory for wriggling like a worm on hard cave floors. It's also a very poor companion for swimming through water-filled cave tunnels, the last adventure of the day. My companions went ahead, and I watched as they sloshed their way down the two foot-high tunnel, the water up to their chins. No doubt, it looked like a lot of fun, and I promised myself that I would return one day, sans camera.

It took just a few minutes for Alfredo and I to make it back to the cavern entrance; he had taught me that a single, main stream always flows out of a cave, and that all smaller streams run into it. If you ever find yourself lost in a cave, just follow the current until it leads you to safety. Our safety was assured, however, not only by the current, but by helpful arrow signs that soon led us to daylight. Emerging, we let our eyes adjust to the bright, white sun, and then hiked back up the grassy hill.

view of arenal volcano from magic mountain

The caves had been absolutely incredible. Their musty smell, incredible colors and ambiance had made for one of the most invigorating, amazing experiences of my life. I had truly gone spelunking: making my way through tight tunnels, sniffing bat guano that dripped off reddish stone, and experiencing five million years' of evolution. It had been the experience of a lifetime. I had seen things that I had only hoped to see in National Geographic, animals such as blind crickets and pincher-less scorpions. My senses felt like they were on fire. Though I hadn't expected it, my trip to the Venado Caverns had been the week's show-stopper.

After the short ride back to La Fortuna, Alfredo took me to Magic Mountain, the last hotel on my itinerary. Located less than two miles from downtown La Fortuna, it has a great location and an incredible view of the volcano. (It's impossible to tire of staring at a smoking, lava-belching mountain, trust me!) I could hardly believe the view from my room: below my third-floor balcony, the hotel pool and jacuzzi stretched out into a green field, which in turn sloped upward into Arenal Volcano. I grabbed my book, plopped down on the balcony, and enjoyed the rest of my afternoon seated at the foot of one of the world's most active volcanoes.

Day 6: Spelunking in Venado Caverns in Pictures

Best Hotel Deals in Costa Rica!

Get up to 30% off Hotels & Resorts worldwide compared to other major booking sites like Expedia and Priceline with our exclusive pricing ...

More Adventures From Our Trip