Changing Planet

Skull in Underwater Cave May Be Earliest Trace of First Americans

Hoyo Negro abyss photo 1.jpgPET/GUE Divers descend into the abyss at Hoyo Negro.

Photo by Daniel Riordan-Araujo


By Fabio Esteban Amador

Explorers have discovered what might be the oldest evidence of humans in the Americas.

Alex Alvarez, Franco Attolini, and Alberto (Beto) Nava are members of PET (Projecto Espeleológico de Tulum), an organization that specializes in the exploration and survey of underwater caves on the Yucatan Peninsula in Mexico.

Alex, Franco and Beto have surveyed tens of thousands of feet of mazelike cave passages in the state of Quintana Roo. The team’s relatively recent explorations of a large pit named Hoyo Negro (Black Hole, in Spanish), deep within a flooded cave, resulted in their breathtaking and once-in-a-lifetime discovery of the remains of an Ice Age mastodon and a human skull at the very bottom of the black abyss.

Hoyo Negro Abyss Photo 7.jpgAfter trekking through the jungle, carrying multiple scuba cylinders, and traveling thousands of feet inside the Aktun-Hu cave system, PET/GUE Member Alex Alvarez discovered a human skull.

Photo by Daniel Riordan-Araujo 

Beto recalls the amazing day of the discovery of Hoyo Negro.

“We started the exploration while following the main tunnel and progressed relatively fast by using scooters to cover more terrain.

“After about 1,500 feet [450 meters] we began to see the light of another entrance, so we headed towards it and surfaced.

“After taking a moment to chat and laugh about what a great dive we were having, we dropped down to continue the work.

“After about 400 feet [120 meters] the tunnel narrowed to form a circular shape, almost like a huge cement pipe. I made one tie-off and, while waiting for Franco to complete his surveying effort, I took a good look at the strangely shaped tunnel.

“All I could see was the whiteness of the cave walls along the sides, and beyond that it was all black. I thought to myself that this is either the largest tunnel I have seen or there is something unusual at the end of it.

“After Franco caught up, we continued for another 200 feet [60 meters] and eventually reached the end of the tube-shaped tunnel. To our surprise the floor disappeared and all we could see was blackness in all directions. It felt like we had reached a big drop-off or the edge of a canyon wall.

“We tried to slow down our heart rates as we were not really sure of what to do next.”

Hoyo Negro Abyss Photo 2.jpgThe Aktun-Hu cave system, where Hoyo Negro is located, is completely filled with water and is fully decorated with speleothems, like the Double Column formation shown in this photo.

Photo by Daniel Riordan-Araujo

Where is Hoyo Negro?

Hoyo Negro was reached by the PET team after the divers travelled more than 4,000 feet [1,200 meters] through underwater passages using underwater propulsion vehicles, or scooters, which enabled them to cover long distances in the flooded cave system.

Once they reached the pit, they began to survey and document its dimensions. The pit is approximately 200 feet [60 meters] deep and 120 feet [36 meters] in diameter and is located inside the Aktun-Hu cave system in the state of Quintana Roo, Mexico.

Submerged cave systems in Quintana Roo have been systematically surveyed and mapped by teams of highly specialized divers. The PET team is affiliated with Global Underwater Explorers, as is the Mexico Cave Exploration Project.

“The immense size of Hoyo Negro is difficult to comprehend. Once you enter the pit you cannot see the floor below, and all that can be seen in front of you is a black void — an inviting entrance to the abyss, ” recalls Franco.

The team of explorers touched bottom at 197 feet [57 meters], where they made their incredible discovery.

How Did the Tunnels Form?

The Yucatan Peninsula’s geology is almost entirely limestone — a karstic shelf that is easily dissolved by rainwater, forming caves and sinkholes.

Approximately 12,000 years ago, at the end of the Pleistocene epoch, Earth experienced great climatic changes. The melting of the ice caps caused a dramatic rise in global sea levels, which flooded low lying coastal landscapes and cave systems. Many of the subterranean spaces that once provided people and animals with water and shelter became inundated and lost until the advent of cave diving.

Hoyo Negro Abyss Photo 3.jpgPET/GUE Diver Alex Alvarez looks at the remains of an extinct mastodon at the base of Hoyo Negro.

Photo by Daniel Riordan-Araujo

Ironically, the Yucatan Peninsula does not have any major rivers or lakes; however, there are many underground rivers and water-filled caves or sinkholes known as cenotes (a Spanish word derived from the Maya dzonot).

What Was Found at the Bottom of the Black Hole?

While the team of explorers conducted various dives for the purpose of mapping and surveying of this newly discovered pit, they noticed some peculiar bones sitting on the bottom. They first came across several megafauna remains and what was clearly a mastodon bone, while subsequent dives proved even more exciting when they spotted a human skull resting upside down with other nearby remains at about 140 feet [43 meters] depth.

“I was searching for more of the mastodon remains, when I saw what looked like a human skull. I had thought we already had a great discovery after finding the remains of several Pleistocene animals…but finding a human skull was totally amazing for us. All of our efforts… walking through the jungle, carrying all the gear, securing the helium required to do such a deep dive, laying thousands of feet of exploration line… paid off at that moment. This is the Holy Grail of underwater cave exploration,” Alex said.

“This is the Holy Grail of underwater cave exploration.”

Soon after the discovery, the team contacted Guillermo de Anda, an archaeologist from the University of Yucatan in Merida (UADY) who has also been documenting Pleistocene megafauna sites and who helped in the identification of the Hoyo Negro discovery.

“The findings of Hoyo Negro are a once-in-a-lifetime discovery. The skull looks pre-Maya, which could make it one of the oldest set of human remains in the area. Gaining an understanding of how this human and these animals entered the site will reveal an immense amount of knowledge from that time. Therefore, protecting and learning the secrets of Hoyo Negro should be one of the main priorities for the archaeologists in the region,” Guillermo told News Watch in an interview.

Hoyo Negro Abyss Photo 4.jpgPET/GUE Diver Franco Attolini places a scale and directional marker near an ancient human skull as part of the team’s recent exploration efforts in the Yucatan Peninsula underwater caves.

Photo by Daniel Riordan-Araujo

The PET team formally announced the discovery at Hoyo Negro to Pilar Luna Erreguerena, Director of Underwater Archaeology for Mexico’s National Institute for Archaeology and History (INAH). Pilar is the founder of underwater archaeology in Latin America and has been instrumental in protecting Mexico’s submerged cultural heritage.

“This discovery is extremely important and confirms the cultural diversity and richness that can be found in the Yucatan Peninsula,” said Pilar Luna. “INAH’s division of underwater archaeology is preparing a multidisciplinary project together with discoverers of the site. This team work will allow us to scientifically recover the data and the evidence in its own context, so that experts may really get to know the true value of this discovery and turn it into a deeper knowledge or understanding of the prehistoric era in this part of Mexico.”

At present, the entrance to the site is limited to INAH’s research team since they are responsible for maintaining the integrity of the site.

Studies in the Tulum area, similar to those currently being planned for Hoyo Negro, were accomplished for the very first time by Pilar Luna’s collaborators, namely Arturo González, Carmen Rojas, Octavio Del Río, Eugenio Aceves, and Jerónimo Avilés, with the support of Adriana Velázquez, Director of Centro INAH Quintana Roo.

Hoyo Negro Abyss Photo 5.jpgGUE and INAH divers participate in a Nautical Archaeology Society training course in Tulum.

Photo by Olmo Torres Talamante

What is the Significance of the Discovery of Hoyo Negro?

The human found with the megafauna remains in Hoyo Negro could represent the oldest evidence of humans yet discovered in the Americas.

Archaeological and genetic data have long supported a northeast Asia origin for the populations that first settled North and South America. The so-called “First Americans” or Paleoindian peoples likely entered into these new lands sometime between 15,000 and 20,000 years ago.

Although a number of early archaeological sites have been excavated, only few sets of Paleoindian remains have been found. A detailed analysis of the human skeletal remains from Hoyo Negro can help us to better understand who these First Americans were and when they arrived here, which is one of the greatest mysteries in American archaeology.

Radiometric dating of the human bones from Hoyo Negro will have to wait for now, but its location within the cave, and its position relative to the mastodon remains, are suggestive of its antiquity.

Hoyo Negro Abyss Photo 6.jpgPET/GUE Divers exit from Hoyo Negro after a long documentation dive where they collected photos and videos of prehistoric remains.

Photo by Daniel Riordan-Araujo

Waitt Institute archaeologist and New World cave expert, Dominique Rissolo, offers a compelling argument for the importance of this site and similar discoveries. “The cenotes of Quintana Roo, Mexico, have emerged as one of the most promising frontiers for Paleoindian studies in the Americas.

“Recent discoveries of human remains deep within the region’s flooded caverns, as well the bones of mastodons and other extinct species of Pleistocene megafauna, offer an extraordinarily rare glimpse into a period that witnessed the peopling of the New World.

“During the Late Pleistocene, these caves were dry. The first people to occupy what is now the Caribbean coast of Mexico wandered into these caves, where some ultimately met their demise.

“As the last glacial maximum came to end, the melting of the polar ice caps and continental ice sheets raised sea levels worldwide. The caves of the Yucatan Peninsula filled with water and the First Americans were hidden for millennia — only to be discovered by underwater cave explorers

“It is within these dark reaches that cave explorers are discovering and documenting the oldest human skeletons yet found in the Western Hemisphere,” Rissolo said.

Future Research at Hoyo Negro

In the summer of 2010, Pilar Luna organized a Nautical Archaeology Society training course for the Hoyo Negro team. The course, which was funded by National Geographic Magazine thanks to Chris Sloan, a magazine editor, covered the essentials of underwater archaeological site recording.

In collaboration with INAH, the team hopes to continue their exploration of Hoyo Negro and to thoroughly document the findings at the site.

Perhaps this is a turning point in scientific exploration in the region, where successful research will depend upon the knowledge and experience of a multidisciplinary team that includes underwater archaeologists, geologists, and paleontologists working side by side with highly skilled divers.

The National Geographic/Waitt Grants Program has funded similar research in the past by supporting GUE diver, Sam Meacham, in his cave exploration and water conservation work in Quintana Roo.

National Geographic has been active in featuring similar discoveries made by cave divers on the Yucatan peninsula. In 2008 National Geographic Daily News published the discovery of the Eve of Naharon, a female skeleton dated to 13,600 years old, which was also found in an underwater cave in Quintana Roo. (Oldest Skeleton in Americas Found in Underwater Cave? )

More recently in 2010, National Geographic Daily News published an article on the Young Man of Chan Hol, a possible ritual burial from 10,000 years ago. (Undersea Cave Yields One of Oldest Skeletons in Americas

In addition to the latest extraordinary expedition and amazing discovery, Robbie Schmittner connected the Aktun-Hu cave system (where Hoyo Negro is located) to the Sac Actun cave system. Together they may now represent the longest underwater cave system in the world.

Future investigations in Hoyo Negro will no doubt reveal new clues about the peopling of the New World.

Fabio-Amador.jpgFabio Esteban Amador is the program officer for the NGS/Waitt Grants Program at National Geographic and an associate research professor of anthropology at George Washington University. He is an archaeologist specializing in Mesoamerican cultures and Pre-Columbian and historic earthen architecture. Amador studied archaeology at Rutgers University and received a Ph.D. from SUNY Buffalo. He has worked in archaeological sites in North, Central and South America and is presently conducting research in Mexico’s Yucatan Peninsula. Before joining National Geographic, he was a professor of archaeology and a researcher for the Council for Scientific Investigation at the National University of El Salvador. Fabio Esteban is also a founding member and coordinator for OLAS (Latin American Organization for Underwater Archaeology), a new community of professionals devoted to the study and conservation of submerged cultural patrimony in the Americas. 

Fabio Esteban Amador’s blog posts

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  • Norene

    I am wondering if the archeologists who visited the secret underwater cave in Mexico considered the possibility that the kill holes in the pottery were just to make the jars sink? Sort of an underwater burial ground? I don’t believe that everything the early peoples did was related to sacrifice and religion. Thank you for considering this viewpoint. Norene

  • Ron Bennett

    Excellent article and photos. A curious link to global warming occurs to me. I’m not an expert, but have been watching the data for global sea level rise as unequivocal evidence of increased global warming. Most data source postulate average global sea level rise of around 6 inches per century for the last several thousand years, increasing to 8 inches per century since the industrial revolution and 12 inches per century since about 1930. Not huge, but a 2X increase is certainly significant. 6 inches per century is consistent with 2000 year old Roman sites now under about 10 feet of water. But your study implies that remains close to 14,000 years old were found about 140 feet underwater, which works out to 12 inches per century – since well before human-caused global warming. Of course subsidence could explain the discrepancy, but it seems on odd coincidence to have 70 feet of sea level rise plus 70 feet of subsidence. Anyone care to comment on whether your discover refutes evidence for a recent human-caused increase in sea level rise? Just kidding, but I would appreciate your thoughts.

  • rebart

    Wouldn’t the salt/any water destroy a skull after all those centuries? I’m having a hard time with this.

  • The Professor

    @Ron, we had a similar problem with concern about the island sinking. It turned out that idiot Gilligan was moving my measuring stick out to deeper water to catch lobster. We’re stuck here forever I guess. 🙁

    At least Mary Anne is still looking hot! 🙂

  • Chad Thomas Graham

    Have any of these artifacts been procured and tested using C13 or C14 dating. That being said our understanding of human evolution and species demands all possible testing available at the time the discovery. Great work.. Now back it up in the Lab. C.T. GRAHAM

  • Matt

    Things like this are incredible, the extent to which human have managed to probe the world is unbelievable and with every question answered introducing a million more NEW questions, it truly is an excellent time for the knowledge hungry individual!

  • AnnMarie

    What amazing finds! I look forward to reading about future discoveries.

  • keith

    How naive is it to think that 30,000 years ago North America was just a barren land without inhabitants. Nat Geo needs to wake up. Zzzzzzzzzzzzzzz.

  • Jesus Salvador

    I’ve been in there many times. The photos do not do the place justice. There are many more skulls, human and some sort of large cat. The large bones which look like big dog bones are about 4 feet long. Alex ruined the dive for everybody. We cave divers with the level of expertise to dive this cave are very religious about our diving. We touch nothing. If your buddy stirs up the slightest bit of dust you talk to him about it after the dive. The idea of taking anything from any cave, especially one like this, only enters into the mind of the Mexican Government and the divers you see pictured here. “Grave Robbers!” That is what they are! They took the oldest human remains ever found in the Americas–a little boy, from his final resting place at Chan Hol. It is guys like us who find this stuff and tell authorities to be helpful. Next thing you know, the government bans the guy who discovered the site with threats of prison. Then, they take the bones. From here on out, when me and my buddies find stuff like this, we are keeping our mouths shut.

  • Bill Z Walton

    Hi! This post could not be written any better! Reading through this post reminds me of my good old room mate! He always kept talking about this. I will forward this post to him. Pretty sure he will have a good read. Thank you for sharing!|

  • Jacob daniels

    Interesting article! I have a problem with the dating method however. You discovered the skull next to fauna that dates to the indicated time; however doing carbon testing would be inconclusive due to the inconstant results caused by carbon fluctuations in maritime areas. I would be interested to see the results regardless. None the less it still wont prove any pre-clovis Hypotheses

  • Dr. Mike

    Small minds can not see beyond what they view. If evidence of man found in America is 13,500 years old, then this is only the oldest evidence, not an indication of the oldest occupation of this land. Kudos to the divers of this extraordinary find. Such
    explorers should be heralded as heros and mentors. Give them
    the respect and freedom to explore they deserve.

  • ‘Victoria Smith

    This is an incredible and revolutionary finding!! I totally agree with Dr. Mike, explorers like these ones who have risked their lives to bring us this knowledge should be heralded as heroes and mentors!
    Sad though to see comments like Jesus Salvador’s one which seem to be out of any real scientific fundament, but probably nothing else but full of envy…
    I guess it is very easy to criticize someone from the comfort of your chair, someone who has made a revolutionary discovery by risking their lives, by diving more than a kilometer into a black hole none else had ever explored before and found incredible pieces of evidence to challenge completely our old school system of beliefs (that the first humans came to the americas by Alaska…).
    I have been as well to the area many times and who ever has been there and is into diving has a big respect for Alex Alvarez, since he was not only the first one to start the diving industry in the Tulum area, but also the first pioneer to start the cave explorer diving in Mexico, everyone knows that and respects him highly for that and because he is most careful and responsible with his work!
    To say that he and the Mexicans authorities are not capable of dealing with this scientific archeological findings is nothing but a comment full of racism, sorry to say… who are you to know how long has passed from the time of the findings to the moment this article has been published and made out public…? I know now for sure this has been years, exactly because Alex knew exactly the major importance of this discovery and he was most careful to do the biggest effort to protect it and bring it out in the right way, at the right time, with the right organizations to protect the findings and enable the best scientific investigation.
    Sorry, Jesus… bring your envy somewhere else… stop trying to bring brilliant people down without real fundaments… why not better risk your own life and make a revolutionary scientific discovery to enlighten the whole of humanity about our unknown natural history instead of being bitter that someone else did it…?

  • Leslie Nelson

    Very interesting article. But as a copyeditor, I must take exception to the term First Americans. Since there was no such place as America or the Americas when these people lived, you should refer to them as first “Americans” in quotes.

  • Carlos Álvarez

    Excelente reportaje de Fabio Esteban Amador, muy bien redactado y documentado, felicidades a todos los involucrados en el hallazgo, especialmente a los buzos Álex Álvarez, Alberto Nava y Franco Atolini, por su iniciativa y su iniciativa y su perseverancia para llevar a cavo un proyecto de tal magnitud de manera desinteresada y en un principio con sus propios recursos. Sin duda un orgullo para México, gracias por compartirlo.

  • j luis moreno c,

    muy interesante este articulo, sobre investigaciones en los cenotes. recuerdo cuando apenas nos atreviamos a penetrar a las cavernas inundadas , han pasado muchos años, Pilar luna ,Guillermo de Anda y otros buzos empezamos estas exploraciones ,la curiosidad y la fotografia me llevaron a documentar estos lugares al lado de Guillermo hice filmaciones , y exploraciones arqueologicas con Pilar . . Felicito a este par de arqueologos que continuan aportando prestigio para nuestro pais.

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