Two University of Texas at Austin researchers snorkeling through an underground stream in Comal County ended up finding a jaw-dropping trove of Ice Age fossils inside a water-filled cave known locally as Bender’s Cave. The material, bones, teeth, and shell fragments scattered across the cave floor, includes animals scientists did not expect to see this far south, and is already prompting a rethink of parts of Central Texas’ Pleistocene history. The discoveries are detailed in a new scientific paper that walks through multiple field trips and dozens of fossil-bearing zones in the cave.
Published March 19 in the journal Quaternary Research, the study is authored by UT Austin paleontologist John A. Moretti and local caver John Young and documents six sampling trips between March 2023 and November 2024. The authors report recovering fossils from 21 distinct zones and describe the assemblage as an underwater lag deposit where elements are often polished and stained by mineral-rich groundwater.
What researchers found
The inventory runs the gamut from proboscidean teeth and camelid bones to more surprising taxa, including fragments of a giant tortoise, armor plates from a pampathere (a lion-sized armadillo relative), a claw from a giant ground sloth, and remains tentatively attributed to saber-toothed cats and Camelops. As reported by Live Science, several of those taxa represent first regional records for the Edwards Plateau.
A different picture of Ice Age Texas
Moretti and Young’s analyses suggest the species mix lines up more closely with sites interpreted as interglacial, warmer intervals of the Late Pleistocene, possibly around 100,000 years ago, rather than the cool, open grassland commonly inferred for Central Texas during the last glacial maximum. The Jackson School of Geosciences at UT Austin notes that statistical grouping placed Bender’s Cave alongside interglacial assemblages from the Dallas area and Gulf Coast, implying parts of Central Texas may once have been wetter and more forested than textbook accounts indicate.
Why dating and context are tricky
Taphonomic signals, including heavy rounding, iron staining, and calcite coatings, indicate prolonged transport and exposure to groundwater, which helps explain the fossil abundance but complicates direct radiocarbon dating. The Quaternary Research paper warns that the assemblage may be time‑averaged, with bones of different ages mixed, and calls for additional geochemical and stratigraphic work to pin down precise ages and associations.
Local cave, wider implications
Bender’s Cave sits on private property in Comal County, and Moretti emphasizes that access and cooperation with landowners made the study possible. Local reporting in CBS Austin notes the team hopes the find will spur controlled surveys of water caves across Texas, which could be an underexplored archive of Pleistocene life.
“This site is showing us something different, and that’s really important,” Moretti said in a UT release, adding that the cave opens “a new window into the past” for Central Texas. The authors say the next steps are targeted dating, expanded sampling, and coordination with landowners to document and protect these underwater repositories before they are disturbed.
