Speleological adventures

Members of the Czech Speleological Society diving on Mexico's Yucatan Peninsula have discovered a previously hidden connection between two caves in the K'oox Baal cave system, making the system the fourth-longest underwater cave in the world at more than 56.5 kilometers.

A team of divers including Zdeněk Motyčka, Radoslav Husák, Jan Sirotek and Daniel Hutňan began exploring the underwater cave systems in Mexico in 2003, completing a total of 10 expeditions there, before finally discovering a connection between two cave systems, the K'oox Baal and the Tux Kupaxa. Hutňan tells The Prague Post the challenge of exploring the caves included putting together a map of the cave system, which had not previously existed.

"You should consider the underwater exploration to be much more demanding than exploration of dry passages," he says. "It was very challenging due to extremely narrow passages with zero visibility we had to overcome by taking off the diving gear underwater and stretching through."

But finding and mapping the cave was only part of the thrill. The caves are full of underwater life, including fish and crustaceans, but Hutňan and the team also made a startling discovery: the skeleton of a sloth that would have lived in the cave some 12,000 years ago. Greg McDonald of the U.S. National Park Service, who was called in to verify the findings, confirmed the importance of this unexpected find.

"I am very excited about the discovery, as scientifically it is a very important specimen for a number of reasons. … I am convinced it is a new genus and species; also, there are very few sloths from Mexico known from complete skeletons, our knowledge of the fossil record of Yucatan is very limited, and the associated cave formations can provide important information on climate change for that part of Mexico," he says.

Natural formation

The discovery of a land mammal in an underwater cave points to the formation of the cave and the way the landscape and climate of Mexico has changed over thousands of years. According to Hutňan, caves on the Yucatan were formed during the Ice Age, when the limestone plate that makes up the peninsula emerged because of a lower ocean level. Rainwater then dissolved the limestone and formed corridors through erosion. Over time, cave formations and sediments were created. At the end of the Ice Age, some 10,000 to 12,000 years ago, the ocean level rose more than 100 meters, and the caves were flooded by salt- and freshwater.

Discovering the cave is only the beginning of the research Hutňan and his team hope to accomplish. Hutňan believes the "enormous maze" of caves under the Yucatan peninsula will continue to be mapped and connected over the next few years.  

"Adding up the length of four cave systems, which are only a few kilometers apart now, would skip the Mammoth cave and pass the imaginary gold medal for the world's longest cave to Mexico. The K'oox Baal system is one of those four caves," he says.

Currently, the Czech Speleological Society is working to create a complex map of the whole K'oox Baal cave system. At the same time, they often travel around the world exploring and mapping similar cave systems, such as the cave known as Bue Marino off the coast of Sardinia.

Stephan Delbos can be reached at
sdelbos@praguepost.com