Cave Divers Swam Through A Subterranean “Portal” – And Found A Long-Forgotten American Land

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Deep in the waters of the Yucatán Peninsula of southeast Mexico, Sam Meacham and Fred Devos are maneuvering their way through a network of caves. The pair have been submerged for some time, having travelled a half-mile or so under the water. Finally, though, they’re faced with a tiny opening in the rock before them. And what lies behind is utterly astounding.

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Meacham and Devos had been swimming through these caves back in the first half of 2017. And they were associated with the Quintana Roo Aquifer System Research Center (CINDAQ), a group hoping to learn more about the natural underground features of Quintana Roo. This is one of three Mexican states located on the Yucatán Peninsula, with the other two being Yucatán and Campeche.

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Now, CINDAQ was set up two decades ago, and since then it has undertaken thousands of dives. And with each new expedition, the organization and its members have become more experienced and capable. Indeed, knowledge about the region’s caves has developed, with a greater picture of the place emerging all the time.

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However, Meacham and Devos’ dive in 2017 was perhaps the most fruitful of CINDAQ’s so far. You see, the items that the pair found behind the opening in the rock were especially important. In fact, their discovery has provided historians with a unique perspective on the ancient human inhabitants of the American continent.

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Given Meacham was actually the director of CINDAQ, the discovery was perhaps particularly poignant for him. Indeed, three years after the event, his memories of that day seem to remain vivid. As he recalled of the opening in the rock to National Geographic in July 2020, “That was the portal into this whole other side.”

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Of course, this particular cave was fascinating, but it’s far from the only one situated in Quintana Roo. In fact, as more research is conducted into the region, it’s become clear that the cave network there is incredibly elaborate. And parts of all this can be found beneath urban centers and tourist spots.

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Interestingly, information on the caves of the Mexican state is compiled by a group known as the Quintana Roo Speleological Survey (QRSS). And according to QRSS, the region is home to slightly more than 400 submerged caves that we know of. In total, this amounts to some 983 miles worth of underground space.

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Now, Quintana Roo is located on the eastern side of the Yucatán Peninsula, a place defined by limestone and its resulting cavernous features. And tens of thousands of years ago, the caves in the area were dry and accessible. However, over the millennia, sea levels rose and ended up submerging the structures.

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Around 10,000 to 12,000 years back, human beings are believed to have accessed the then-dry caves of Quintana Roo. And they wouldn’t have been alone in doing so. That’s to say, there’s evidence that large creatures such as the giant ground sloth and the saber-toothed cat once showed up, too.

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Of course, today the caves are uninhabitable. Yes, they’re underwater and can only be reached through openings in the rock known as cenotes. Given this, it’s difficult to investigate these natural features. But having said that, discoveries have been made in the caves over the years. Among the most significant, perhaps, was the finding of a female skeleton in 2007.

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Unbelievably, these human remains were about 13,000 years of age and found in a cave called Hoyo Negro. And researchers named the skeleton Naia, in reference to Greek water apparitions called naiads. When she died, it seems that Naia was 15 or 16 years old and 4 foot 10 inches tall.

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Now, Naia’s discovery is vital because she’s potentially a “missing link” between early American settlers and today’s Native American community. In other words, genetically speaking, Naia exhibits many similarities to contemporary Native American people. In fact, the suggestion is that Naia’s people are distant cousins.

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Furthermore, James Chatters headed up a study related to the genetics of Naia. And speaking to Live Science in the wake of the discovery, he gave his own thoughts. He said, “Naia is a missing link filling in a gap of knowledge we had about the earliest Americans and modern Native Americans.”

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The cave where Naia was found – Hoyo Negro – is part of a network called Sac Actun. And this underground labyrinth snakes through the tropical lands of Yucatán Peninsula’s east. As Chatters explained, “Hoyo Negro is a more than 100-foot-deep, bell-shaped, water-filled void about the size of a professional basketball arena deep inside a drowned cave system.”

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And diver Alberto Nava has detailed the moment of Hoyo Negro’s 2007 discovery. He told CBS News, “We had no idea what we might find when we initially entered the cave, which is the allure of cave diving. The moment we entered the site, we knew it was an incredible place. The floor disappeared under us, and we could not see across to the other side.”

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Nava went on, “We pointed our lights down and to the sides. All we could see was darkness. We felt as if our powerful underwater lights were being destroyed by this void, so we called it Black Hole (a cosmic object that absorbs all light), which in Spanish is Hoyo Negro.”

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As we’ve mentioned, it wasn’t just human beings that entered these caves thousands of years ago. Indeed, evidence of a wide range of sizable creatures has been found there in contemporary times, and that’s not to mention signs of plant life. As Chatters put it, “It is a time capsule of climate, and plant, animal and human life at the end of the last ice age.”

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What’s more, experts have theorized that the creatures found in this cave must have slipped to their deaths and remained trapped inside for millennia. Then, over time, glaciers around the globe began to melt. As a consequence, sea levels rose, and the cave became submerged beneath the water.

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So the discovery of Naia made it plain to see that ancient humans once entered the caves of Quintana Roo. But why exactly would they have done this? Well, the team at CINDAQ may have gone some way to finding the answer, after Sam Meacham and Fred Devos made an amazing discovery of their own.

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Yes, in early 2017 Meacham and Devos were submerged deep underwater, investigating a particular cave known as La Mina. And by maneuvering through a tough environment of sharp, protruding rock, they eventually made it to the tiny entrance of the cave. Going inside, they likely became the first people inside La Mina in roughly 10,000 years.

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However, Meacham and Devos weren’t the last people to swim in the cave of La Mina. For you see, Eduard Reinhardt, a geo-archaeologist and diver himself, soon followed the pair. Detailing his own experience of the cave and the larger system within which it sits – a place he compared to “Swiss cheese” – Reinhardt reflected, “This was a bonanza.”

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As told to CBC News, Reinhardt went on to explain just how dangerous diving around La Mina can be. “You have to be very, very careful about not getting lost,” he stated. “You’ve got passages that kind of loop around and interconnect and then branch off and then connect into other systems.”

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Furthermore, some of the spaces that one has to traverse to get to La Mina can be extremely challenging. For instance, a lot of the passages can measure 80 feet wide but with ceilings lower than 6.5 feet high. Others can span just over 2 feet in width. Reinhardt said, “You’ve really got to basically get on your back and kind of wiggle your way through.”

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Carefully, though, Reinhardt – and, of course, Meacham and Devos before him – made it inside of La Mina. It was quite the feat, especially given all of the obstacles that stood in their way. But what exactly did they find after they’d weaved their way through this underwater maze?

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Well, the cave exhibited signs that ancient humans had been inside long ago. Tools made of rock littered the site, and there was evidence of fires having been lit in the cave. But why were people descending into these caverns? Were they looking for drinking water? Or were they perhaps laying their dead to rest down there?

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Roberto Junco is the head of Mexico’s archaeological regulatory organization, the Underwater Archaeology office of the National Institute of Anthropology and History (INAH). And Junco put forth the prominent theory to National Geographic. He said, “Now we have really, really strong evidence that at least one of the reasons… was for the mining of ocher.”

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You see, inside La Mina, an apparent site of labor was discovered in amazing condition. All the tools and pits for fire inside the underwater site pointed towards one thing. This place had been where ancient people came to mine for red ocher, a pigment used all over the globe in cave artworks, religious practices and as an ingredient of sunscreen.

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And the findings have been detailed in the journal Science Advances. One of the contributors, Brandi MacDonald, specializes in ocher pigments. Speaking to National Geographic, MacDonald said, “I’ve spent a lot of time imagining the different ways that people in the past have gone about collecting mineral pigments. But being able to see it like this in such an interesting state of preservation, it just blew me away.”

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Speaking to the same publication, Meacham recalled the moment that he and Devos first noted all these man made features in the cave. “Fred and I immediately just started pointing at all of this stuff,” he remembered. “It’s not natural, and there’s nothing that could have done this other than humans.”

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Given that the CINDAQ team had come across strong evidence of mining activity in La Mina, past discoveries started to make more sense. As Meacham said of previous expeditions, “We’ve noticed these strange, out-of-place things.” Generally speaking, this often meant that rocks were found in places where you wouldn’t otherwise expect them to be.

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Now that La Mina has all but been confirmed as an ocher mining site, researchers can comfortably draw conclusions about other underwater caves in the area. Because it seems likely that two others were used for the same purposes. Thanks to carbon dating techniques, we can say that all three places were functional from 10,000 to 12,000 years ago.

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What’s more, it seems probable that there are more mining sites out there in Quintana Roo. As Eduard Reinhardt put it to National Geographic, “It’s not just a one-off sort of thing. There was an active program to prospect, find, and extract ocher. There’ll no doubt be more locations.”

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Since its discovery, a whole host of additional expeditions have ventured to La Mina. These have retrieved samples for scientists to pore over, but they’ve also achieved something else. That is, they’ve taken photos and footage of the site, which has been utilized for the sake of creating a 3D rendering of the cave.

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That aside, La Mina has painted a picture of an ancient people with quite a sophisticated level of knowledge. For example, charcoal discovered in the mine appears to have been selected for its capacity to burn for a long time. Plus, we can see how they went about tackling the extraction operation.

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Basically, it seems that the ancient peoples extracted ocher in lines, exhausting a given section until there was no pigment left. Then, they would move onto a new section. As the University of New Hampshire’s Barry Rock told National Geographic, “They understood… some basic geological principles that weren’t really codified or formalized until the mid-1600s.”

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But why were these ancient people going to the trouble of retrieving ocher from La Mina? Well, they were far from the only groups doing so in ancient times. As far back as 100,000 years ago, people in South Africa were using the pigment. In France, evidence of its use from 30,000 years ago has been found, whereas in Spain a 19,000-year-old female body was found coated in it.

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To add to that, the pigment has been utilized for more functional reasons over the years, too. Yes, ocher has been used as a sort of glue for binding tools together. It has also been used as a repellent against irksome insects. However, it’s still unclear how the people working in La Mina were making use of it.

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It’s been suggested, though, that La Mina may have been a site of religious significance. You see, the University of California Merced’s Holley Moyes is an expert on how caves have been utilized for spiritual reasons. And though she wasn’t involved in the La Mina project herself, she’s nonetheless given her two cents on the matter.

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Speaking to National Geographic, Moyes said, “Caves produce all kinds of good and evil. They’re probably the most sacred natural feature.” The Maya civilization of Mesoamerica were notably fond of utilizing the spaces for spiritual reasons, and they also made use of ocher. As Moyes explained, “It’s something about that red color.”

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So although we don’t yet understand what the ocher taken from La Mina was used for, the discovery has undoubtedly been exciting. As Roberto Junco of the INAH has said, “We’re super excited here in Mexico to be working on this project. This is truly one of those moments where there’s a big change in the game.”

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