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Saber-toothed cat skull newly discovered in Iowa reveals details about this Ice Age predator


The saber-toothed cat is an ice age icon And emblem of strength, tenacity and intelligence. These animals shared the North American landscape with other large carnivores, including short-faced bears, dire wolves, and the American lion, as well as megaherbivores, including mammoths, mastodons, musk oxen, and long-horned bison. Then, at the end of the Pleistocene, between 50,000 and 10,000 years ago, they are all gone. The only place to see them now is in the fossil record.

However, carnivore fossils are extremely rare compared to those of their prey. Prey is always more abundant than predators in a healthy ecosystem. So the probability of burial, storage and discovery of bones and teeth of carnivores is therefore small compared to that of herbivores.

Scientists have a relatively small and scattered inventory of saber-tooth fossils. The exception comes from Rancho La Brea in downtown Los Angeles, where beyond 1,000 individual saber teeth were entangled in deadly tar leak traps.

That’s why the recent discovery of a stunning saber-toothed cat skull in southwestern Iowa is so exciting. The Smilodon fatalis skull was collected from late Pleistocene sands and gravels exposed along the East Nishnabotna River. My colleague, biologist David A. Easterla, and I Are study this copy to find out more about the life history, prey selection and eventual extinction of this ancient predator.

The recent saber-tooth find is a complete skull, although one of his eponymous sabers is missing.
Chris Gannon, ISU News Service

Clues from a skull

The animal’s common name – saber-toothed cat – comes from its very distinctive, saber-like fangs that protrude as much as 13 to 15 centimeters from the mouth.

Sabertooths are sexually dimorphic, with males generally larger than females. Iowa’s skull is larger than that of many adult males from Rancho La Brea. Several bones of the skull are not bonded together and the teeth are essentially unworn, leading us to believe that this individual was almost certainly a young man between the ages of 2 and 3 who was still growing.

We estimate he weighed 250 pounds. That’s more than 110 pounds (50 kilograms) more than the average adult male African lion. Had he had a few years to mature and plump up loose skin, he might have tipped the scales at 300 pounds.

Observations of the life cycles of modern lions and tigers suggest that this saber-tooth was newly independent or about to start living on its own.

four lions attacking an African buffalo
Saber-toothed cats may have lived and hunted together in groups like modern lions, but all other modern cats live more solitary lives.
jez_bennett/iStock via Getty Images Plus

However, it is hotly debated whether saber-teeth stayed together in groups or were loners. Disagreement revolves around how much difference in size there is between men and women. In many living animals males are usually larger than females in male-dominated harems, as in modern lions. In the case of saber teeth, some scholars identify this pronounced sexual dimophisim between the sexes and claim that these ancient cats lived in groups similar to today’s lions. Other researchers see only minimal size differences and look at saber-toothed cats generally as solitary predatorsmaybe more like tigers and all other felines.

Be that as it may, by age 2 or 3, the cat clearly possessed the guns — jaws and paws — and the weight to take on large prey on its own. He probably gained experience hunting by first watching his mother locate prey, pursue, ambush and kill, and defend the carcasses, then perhaps with her help, and finally alone. Its learning curve was probably much like lions and tigers as they mature physically and behaviorally.

Hunting for survival is a high stakes. Repeated failure means death by starvation. And attacking large prey equipped with defenses such as horns, antlers, hooves and trunks is always dangerous and sometimes deadly. For example, a recent study of 166 modern lion skulls from Zambia revealed that 68 had healed or partially healed injuries associated with taking down prey. In other words, 40% had survived major head trauma to hunt another day.

frontal view of a saber-toothed cat's skull, showing only one long tooth on the right side
One of this cat’s signature sabers was broken off before he died.
Chris Gannon, ISU News Service

A saber in Iowa’s skull has broken off where the fang emerges from the palate. Morphological details of the fractured edges indicate that the damage occurred around the time of this animal’s death. It is possible that the fracture is related to a defensive wound thanks to a prey animal’s well-placed hoof, antlers, horn, or whack. Since the stump is not worn out, the encounter may have even caused the cat’s death.

Additional technical analysis provides more info

Called a technique stable isotope analysis allows researchers to figure out what an animal ate and even where it lived based on isotope ratios in its teeth or bones.

Andrew Somerville, a specialist in isotopic biogeochemistry, is leading this effort with the Iowa sabertooth. Our team suspects that saber-toothed cats in this area may have focused their hunting on the Jefferson’s ground sloth, a huge, bulky and lonely browser. With adults weighing about a ton, its size was probably an important deterrent to other predators, but not necessarily saber-toothed. Sharp sabers in the neck could have killed the sloth, damn big.

My colleagues and I are also developing what natural science researchers call diet-wide mixing models. Using stable isotopes of carbon and nitrogen preserved in Ice Age carnivore, herbivore, and omnivore bones from southwestern Iowa, our models should tell us whether saber-toothed, short-faced bears, and dire wolves competed for the same prey , the habitats where they foraged for prey, and, possibly, how these food web connections collapsed at the end of the Ice Age.

carbon dating indicates that this Iowa saber-tooth lived between 13,605 and 13,455 years ago, making it one of the last of its kind to walk the western hemisphere. Slightly younger dates – but not much – come from Rancho La Brea, eastern Brazil and the very south of Chile.

These dates mean saber teeth and the first humans to infiltrate these places – Clovis collectors in North America And Fishtail collectors in South America – shared the landscape for a short time. Humans have likely come across saber-toothed marks, scat, and kills every now and then. Perhaps a few lucky people have seen the beautiful animal live its life. But neither knew what the future held.

The big cat disappeared from both continents shortly after humans arrived. The ultimate cause of the die-off is difficult to determine and there were certainly several factors at play. But at least with saber teeth, we can say that extinction was a hemisphere-wide synchronous event that occurred in a geological moment, perhaps only 1,000 or 2,000 years from now, which makes it difficult to tie people directly or indirectly to the extinction.

The Iowa skull, combined with other fossil evidence from the region and observations of modern large carnivores, has shed new light on the life history and behavior of saber-toothed cats. Ongoing research promises to provide additional clues about the diet and ecology of this iconic predator.

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