The discovery of old cat bones found deep inside the dark cavernous earth has enthralled scientists at Natural Bridge Caverns for more than six decades now.
But the last couple of years have gotten especially interesting.
Texas paleontologists and biologists recently found two nearly complete skeletons of wild cats deep inside the commercial caverns north of San Antonio, which see over 250,000 visitors each year.
And now thanks to advancements in science such as DNA sampling, they are finally closing in on answering lingering questions. Lead paleontologist and UT doctoral candidate John Moretti says they are still trying to find out exactly what kind of cat they found and how they got there.
The first of the two jawbones was originally discovered in 1963 by Orion Knox Jr. — one of the caverns’ founders — as part of a cat skeleton. Pieces of those skeletons are now at the University of Texas’ collection in Austin. However, unbeknownst to the Wuest family who own the property, Knox left pieces behind.
For a long time, it was believed the bones were from a simple Texas bobcat — a myth Knox himself perpetuated, said Brad Wuest, the third-generation owner, president and CEO of Natural Bridge Caverns.
Proteins discovered still intact on the skeletons revealed that both sets of bones had belonged to two small wild cats that had likely been alive 11,500 years ago.
“That puts them all way back in time in the Pleistocene Epoch — the Ice Age, when woolly mammoths, saber tooth cats and ground sloths were still running around here on the surface,” Moretti said.
Using carbon dating and DNA sequencing, Moretti and his team have now been able to narrow down that the bones likely come from one of three ancient species: either a margay or jaguarundi — both of which are still alive today as endangered species that live in Mexico and Central America — or a third, now-extinct but closely related ancestor of these two.
“We can now answer some really big questions with these little skeletons,” Moretti said. “Which is really, really cool.”
An accidental discovery
The discovery of the left-behind bones and the second cat started with a shoe getting stuck in ankle-deep mud.
In March 2022, Wuest and a small team of biologists had been in the caverns working to collect data on the cave-adapted species of invertebrates — such as insects, bugs and snails.
During this particular expedition, the sole of biologist Jean Krejca’s boot had gotten stuck in the sticky clay mud that coats much of the bottom of the caverns’ natural passages. The mud had been so tacky that it had ripped the sole of her boot off as she tried to get unstuck, said Wuest. Krejca left the caverns to go get another pair of boots.
It was while Krejca had been working her way back to the group that she’d first spotted a set of cat tracks, which she mentioned off-handedly after returning to her peers.
The prints, impressions of claw marks and toe pads, would help give Moretti and other scientists clues to the two cats’ last moments alive.
After a three-day retrieval process collecting both skeletons in early 2023, Moretti was later able to confirm that one of the sets of bones was in fact from the same cat as the jaw bone being housed at UT since the 60s.
Finding proteins intact enough to be DNA sequenced off of ancient remains in Texas is extremely rare, Moretti explained, unless they are kept in a cool arid space like a cave. Natural Bridge Caverns in this instance acted sort of like a refrigerator, Wuest said.
Together, the bones, DNA and paw prints tell a story of two ancient cats, likely related, that wandered into the caverns together, where they both tried to maneuver around in total darkness only to each meet tragic fates.
Over the past year and a half, Moretti has worked with David Ledesma, a UT doctoral candidate who specializes in ancient DNA extraction, and paleobiologist Melissa Kemp, an assistant professor at UT who specializes in using ancient DNA fragments to identify reptile and amphibian fossils from cave samples.
The group was able to confirm the two cat skeletons contained DNA fragments consistent with ancient DNA. They have continued to work on narrowing down the exact species of the cats by creating “species scorecards.” These allow Moretti, Ledesma and Kemp to systematically compare DNA traits from each cat to those from dozens of possible species.
Moretti is also still working with a third-party company to collect data on the paw prints with a portable radar detection system. Once measurements are taken, he will be able to see if the foot bones of the cats correlate with the size of the pawprints. The analysis will help confirm that the prints in the prehistoric cat passageway are from the two related cats.
Complicating the matter was the discovery of a third cat shortly after the first two. This cat was found much closer to the entrance of the caverns, however, the age of these bones only appears to be a century old — much more recent than the other two skeletons.
Scientists and the Wuest family are still baffled by how the cats got there. Their whereabouts in the cave suggest there may have been at one time another entrance into the caverns.
“There are literally millions of places they could have died if they would have come in the natural entrance,” Wuest said. “It’s hard to imagine that they could have traveled a mile back into the cave, avoiding just pitfalls everywhere … It just seems like that’s almost hard to believe. And so that’s part of the mystery here. How in the heck did these cats get in the cave?”
