Sabertooth cats once roamed Iowa, archaeology discovery confirms

The East Nishnabota River carves through southwestern Iowa, flowing over sands and gravels dating back to the last ice age. In 2017, something emerged from the riverbanks that would change Iowa’s archaeological history: a skull, marked by an iconic, long canine tooth.

Sediment embraced the fossil for more than 13,000 years until it was exposed by the elements. And, by the luck of the draw, it was found.

“When I first saw the pictures of it, I didn't believe it … By and large, ultimately, it turned out to be true,” said Matthew Hill, an associate professor of archaeology at Iowa State University. “It's not just a broken tooth or a bit of a skull. It's the complete thing. It's the whole shebang. It's spectacular. The preservation of it is second to none. It's beautiful.”

Hill said the person who found the skull has asked to remain anonymous, and the exact location of its discovery is being kept quiet to discourage follow-up artifact hunting.

“It's not just a broken tooth or a bit of a skull. It's the complete thing. It's the whole shebang. It's spectacular. The preservation of it is second to none. It's beautiful.” — Matthew Hill, Iowa State University

On and off for four years, Hill analyzed the skull with David Easterla, a biology professor emeritus at Northwest Missouri State University. They found it once belonged to a young male sabertooth cat — marking the first evidence of the iconic ice age predator in Iowa. Their findings were published this month in the peer-reviewed journal Quaternary Science Reviews.

“It's been very exciting. We learned a heck of a lot from one specimen,” Hill said. “If you know what to look for on the specimen, one little thing can reveal a whole lot of information its life in the past.”

A rare find

Iowa hosts a laundry list of ice age fossils, like dire wolves, caribou, giant short-faced bears, giant ground sloths — just to name a few.

But the newfound sabertooth skull is the first evidence of the predator ever living in the state. The next-closest discoveries were found in southeastern Missouri, northeastern Kansas and Oklahoma.

It adds to a collection of only about 70 existing sabertooth fossils across the country, making it an extremely rare archaeological find. That’s because animal populations get smaller moving up the food chain — both today and millennia ago, Hill explained.

“When you look at the Serengeti on your documentaries, we have lots and lots of wildebeests and zebras, for example. But only a handful of lions, leopards and cheetahs,” he said. “We’re moving up the food chain, and they become rarer.”

Detective work

Only the skull was found — the lower jaw and the rest of the skeleton were lost with the past. But, with careful analysis, the remnant still provided clues into the life of the sabertooth cat it once belonged to.

The skull is made up of several connected plates. Those plates weren’t fully sealed yet, signaling that this animal wasn’t done growing — even though it was already bigger than the mature male sabertooth skulls found in Los Angeles tar pits, Hill said.

That comparison meant this sabertooth cat was likely a male, too, since female cats were smaller. The skull’s owner likely weighed about 550 pounds at death, surpassing the size of today’s average African lion adult male.

For more evidence, Hill looked at the teeth: They were permanent adult teeth, but they weren’t worn down much. That means the sabertooth cat hadn’t lived long enough to prominently grind down its tooth by chewing its food.

He estimated the cat was around two or three years old when it died. How did it die? That’s still unclear — but, again, its teeth leave behind some clues.

The skull is missing one of its iconic canines. The stub left behind isn’t worn down, suggesting that the tooth broke off close to the cat’s time of death.

“We think that possibly one of the canines was broken during an encounter with a large animal, potentially a prey,” Hill said. “Traumatic injuries to the head are pretty common in large carnivores that hunt large herbivores … It's a really rough way to live.”

Aside from physical attributes, the researchers also used radiocarbon dating to uncover when the animal died. Radiocarbon dating measures the amount of decaying carbon in organic matter to figure out how old it is.

The researchers determined that the cat died between 13,605 and 13,460 years ago at the end of the most recent ice age. Its body was buried quickly, sealed off and protected from the elements until it was found in 2017.

“It's the fourth-youngest radiocarbon-dated sabertooth cat in the Western Hemisphere at present,” Hill said. “That means that extinction probably happened shortly after this animal died.”

Next steps

Researchers can still learn more from the sabertooth skull. Specifically, Hill said he’s hoping to research the prey of prehistoric large carnivores.

To do so, he is teaming up with Andrew Somerville, an ISU assistant professor of archaeology. They will investigate the chemistry of the sabertooth cat’s skull — along with the bones of other prehistoric carnivores — to figure out what types of animals they ate.

“You are what you eat,” Hill said. The researchers expect to publish their findings in the coming year.

On top of that, this 13,000-year-old fossil adds another piece to the puzzle of why ice age animals went extinct in a “geological instance,” Hill said. Sabertooth cats became extinct between 12,000 and 13,000 years ago.

Some researchers think human hunters are responsible; others blame climatic change.

“It’s a huge thing,” Hill said about the lack of scientific consensus. “It involves not just archaeologists, but also ecologists, mammalogists, all sorts of people. Depending on the discipline that you're in, you think differently.”

Brittney J. Miller is the Energy & Environment Reporter for The Gazette and a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues.

Comments: (319) 398-8370; brittney.miller@thegazette.com