Fossilized remains of Ice Age animals recovered from a privately owned Spring Branch water cave by University of Texas paleontologist John Moretti could rewrite Central Texas’ geologic history.
Shell fragments found lying on a streambed are from 100,000-year old extinct creatures never discovered in Central Texas before.
In a March 19 paper published online by Cambridge University Press, Moretti said evidence suggests an interglacial period could have warmed the region enough to sustain giant tortoises and pampatheres, ancient armadillos the size of a lion.
The Bender’s Cave fossils have a lot in common with fossil sites in the Dallas area and Gulf Coast that are known to date back to the last interglacial period. Fossils from the giant tortoise, pampathere, and ground sloth have been found in these areas.
When Moretti conducted a statistical analysis that grouped Ice Age sites in Texas based on the similarity of their fossils, Bender’s Cave was grouped with these interglacial sites rather than sites in Central Texas, according to a statement from the University of Texas.
The ground sloth and mastodon were forest dwellers, and the giant tortoise and pampatheres needed warm temperatures to thrive. The warmer interglacial periods may have had both these things. In contrast, during the cool glacial interval, Central Texas was a sprawling grassland.
David Ledesma, an assistant professor at St. Edwards University who studies how lizards, frogs, and other small animals responded to environmental changes during the past Ice Age, said that the research shows that even in an area as well-documented as Central Texas, there are new things to find.
“Some of the fossils that John has come across are species that we didn’t think would occur in this part of Texas,” said Ledesma, who was not part of the study. “That we’re still learning new things and finding new things is quite exciting.”
Moretti and John Young, a paramedic and spelunker, made six trips to Bender’s Cave between March 2023 and November 2024.
Snorkeling in wet suits through an underground stream they discovered giant tortoise shell fragments, a giant ground-sloth claw, bones, teeth, armor from a pampathere (ancient armadillo the size of a lion), bones from saber-tooth cats, camels and mastodons on the streambed.
“There were fossils everywhere, just everywhere, in a way that I haven’t seen in any other cave,” Moretti said in a statement. “It was just bones all over the floor.”
According to the March 2010 issue of Texas Caver, Bender’s Cave was located inside a large ranch purchased by a developer in 2005. By 2006 the ranch was subdivided into a residential neighborhood.
Several cavers located the lot with Benders Cave and inquired about the purchase price.
The listing price was $250,000.
In June 2006 the owner/developer allowed cavers to take a look around.
The nonprofit Texas Cave Management Association (TCMA) decided the price was too steep.
“We knew it to be a nice long water cave, but the cost was just not reasonable,” Kurt Menking said.
But during a real-estate slump in 2010 the asking price fell to $156,000.
B.T. Price of Bexar Grotto helped arrange financing but unbeknownst to cavers also planned to build a house on the property.
He gated the lot to keep out new neighbors who “discovered” the cave, leaving behind old inner tubes, plastic bottles, Styrofoam blocks and blow-up floaties of all shapes and sizes.
Moretti said most caves are on private property.
Refining the picture of prehistoric Texas requires landowners and scientists to work together to explore the past.
“These connections and partnerships make possible a lot of the natural science that gets done in Texas,” he said. “It takes contributions from everyone — not just scientists at universities — to learn about the natural world we live in and depend on.”