When paleontologists entered a cave on private property in Comal County, Texas, they had hoped they might find some clues about the region’s ancient past.
However, the rare ancient discovery they made upon entering hadn’t been on their bingo card.
Now, the findings by a paleontologist from The University of Texas at Austin have confirmed the presence of fossil remains belonging to ancient land animals last seen by human eyes at the end of the Ice Age, and in a part of Texas no one expected to find them.
The discoveries include the remains of a giant Pleistocene-era tortoise, as well as those belonging to a pampathere, a relative of the armadillo, although one much larger than its modern-day cousin.
Paleontologist John Moretti, who made the discoveries while snorkeling in the underground cavern, known locally as Bender’s Cave, said they were among dozens of other fossil discoveries that were made during the first recorded scientific study involving the cave’s paleontological treasures.
“There were fossils everywhere,” Moretti recently said, “just everywhere, in a way that I haven’t seen in any other cave.”
“It was just bones all over the floor,” said Moretti, the recent recipient of a doctoral degree from the UT Jackson School of Geosciences.
Moretti believes most of the ancient bones made their way into the cave through sinkholes over the years, after which fossil formation processes preserved their likeness until the present day.
Some of the fossils, he believes, could even date back 100,000 years, coinciding with a relatively warm period scientists call the last interglacial period. The discoveries offer a rare opportunity to paleontologists like Moretti, since conditions in Central Texas weren’t conducive to the formation of fossils, leaving few fossils from this period.
“If it is interglacial in age, it’s a new window into the past and into a landscape, environment, and animal community that we haven’t observed in this part of Texas before,” Moretti recently said.
The findings, detailed in a new study published in Quaternary Research by Moretti and his co-author, local caving enthusiast John Young, detail half a dozen trips to the cave between early 2023 and November 2024. Fossils were collected from stream beds within the cave as the researchers wore snorkeling gear, where sifting through the stones and other material produced fossils from Ice Age megafauna that included American camels, mastodons, giant ground sloths, and saber-tooth cats.
While dating the fossils is a bit complicated, Moretti believes there are a few indications that point to the likelihood they date to the last interglacial period, which includes the habitats of the animals whose fossils are present within the cave. Forest-dwelling megafauna, such as mastodons, as well as the giant tortoise and pampatheres, all have one thing in common: they required warmer temperatures, relatively speaking, which would have coincided with interglacial periods.
Also, the discoveries by Moretti and Young are similar to other finds from caves in other regions, but which also date to the last interglacial period. Based on such similarities, statistical analysis comparing Bender’s Cave with other such sites successfully grouped it alongside these known interglacial sites.
“Some of the fossils that John has come across are species that we didn’t think would occur in this part of Texas,” David Ledesma, an assistant professor at St. Edwards University who called the new research a surprising—and exciting—addition to our knowledge of the fossil prehistory of Central Texas.
“That we’re still learning new things and finding new things is quite exciting,” Ledesma said.
Moretti and Young’s recent paper was published in the March issue of Quaternary Research.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.