{"id":370907,"date":"2026-06-23T01:08:02","date_gmt":"2026-06-23T01:08:02","guid":{"rendered":"https:\/\/www.newsbeep.com\/us-ca\/370907\/"},"modified":"2026-06-23T01:08:02","modified_gmt":"2026-06-23T01:08:02","slug":"new-research-on-evolutionary-history-of-saber-toothed-cats","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us-ca\/370907\/","title":{"rendered":"New Research on Evolutionary History of Saber-Toothed Cats"},"content":{"rendered":"

A misidentified skull in a museum collection turned out to be a very early saber-toothed cat, highlighting the evolutionary tendency toward longer and longer fangs.<\/p>\n

\"heads
\nAn artist\u2019s rendering of what the early saber-toothed cat, Adelphailurus kansensis, might have looked like in its heyday 5 million years ago. About the size of today\u2019s mountain lions, the cats already had teeth optimized for slicing and shredding flesh, though the fangs were much smaller than those of later sabertooths, such as the iconic Smilodon. J. Gomarra for UC Berkeley<\/p>\n

Fossils tucked away in a museum drawer and identified merely as \u201cfeline\u201d are actually from a very ancient and enigmatic saber-toothed cat that inhabited North America more than 5 million years ago. Newly identified by a UC Berkeley paleontologist, the nearly complete skull helps clarify how these large-fanged felines evolved over millennia before going extinct about 10,000 years ago.<\/p>\n

One clear takeaway is that these cats started out with smaller fangs \u2014 the upper canines \u2014 but evolved increasingly longer ones that may have led to their ultimate demise. California\u2019s state fossil,\u00a0Smilodon fatalis\u00a0(originally called\u00a0S. californicus), was the culmination of that trend. It had some of the largest upper canines of any saber-toothed animal \u2014 up to 7 inches long \u2014 but was the last saber-toothed animal to survive.<\/p>\n

According to Berkeley postdoctoral fellow\u00a0Narimane Chatar<\/a>, the cranium, teeth and lower jaw (or mandible) she stumbled upon in the American Museum of Natural History in New York are from the species\u00a0Adelphailurus kansensis, originally discovered in Kansas and known only from jaw fragments and teeth. Now, with the first complete skull of the cat, she has been able to tentatively place the animal within the family tree of saber-toothed carnivores and contrast it with the most recognizable saber-toothed cat,\u00a0Smilodon, which ranged throughout the American continent.<\/p>\n

\u201cBack in the days when we thought about sabertooths, we thought \u2018Smilodon\u2019\u00a0and that\u2019s it. We thought that all species that exhibited a somewhat saber-like tooth morphology must have hunted like\u00a0Smilodon\u00a0and behaved like\u00a0Smilodon,\u201d Chatar said. \u201cWe are now starting to see a great disparity within those animals, and especially in the early diverging taxa, like\u00a0Adelphailurus kansensis.\u201d<\/p>\n

\"image
\nSee video HERE<\/a>. A 3D scan of the newly identified fossil skull of\u00a0Adelphailurus kansensis, a saber-toothed cat from an ancient lineage before the cats developed their extra-long upper canines. Though upper canines from similar animals were found near this cranium in Arizona, the fossil was not found with canines attached. (Credit: Narimane Chatar and American Museum of Natural History) Narimane Chatar and American Museum of Natural History<\/p>\n

Adapted for slicing flesh and severing arteries, the upper canines differ from those of today\u2019s cats in being flattened laterally, like a knife, instead of having a round cross-section like the canines of lions, tigers and house cats. Their premolars are also like knives, suitable for chopping and shredding meat.<\/p>\n

But saber-shaped teeth are more fragile than the sturdier teeth of today\u2019s felines, as previous research has shown. Chatar herself has tested the sturdiness and killing efficiency of\u00a0sabertooth upper canines<\/a>\u00a0and is currently conducting experiments on carnivore molars in the lab of Jack Tseng, a Berkeley professor of integrative biology. In simulations, 3D-printed saber teeth from various species proved ideal at penetrating a gel with the consistency of flesh but fractured easily against simulated bone. In the former tests,\u00a0Smilodon\u00a0came out on top. In the latter,\u00a0Smilodon\u00a0fared the worst.<\/p>\n

Perhaps as a result of their fragile dentition, when these fierce hyper carnivores lost their preferred food \u2014 large plant eaters like bison and camels, which died out after the last Ice Age \u2014 they were outcompeted by carnivores with rounder and sturdier teeth, not to mention bone-crunching molars.<\/p>\n

\u201cSlicing and crushing are basically the two main things a carnivorous mammal\u2019s teeth can do,\u201d Chatar said. \u201cBut for saber-toothed animals, there\u2019s a clear trade off. Those upper canines were extremely efficient but also break very easily.\u201d<\/p>\n

The\u00a0new fossil was described in a paper<\/a>\u00a0published online June 19 in the\u00a0Journal of Vertebrate Paleontology.<\/p>\n

Were saber-like teeth a dead end?<\/p>\n

Despite the ultimate extinction of saber-toothed animals, for several tens of millions of years large upper canines were a thing. They were found not only in two groups of felids (the group that includes living cats) \u2014 sabertooths such as\u00a0Smilodon\u00a0and scimitar-toothed cats called Homotherini \u2014 but also in a group of marsupials called\u00a0Thylacosmilids\u00a0in South America and an ancient lineage of cat-like carnivores called\u00a0Nimravids.\u00a0Thylacosmilus, which died out several million years ago, had continuously growing saber teeth that rivaled those of\u00a0Smilodon.<\/p>\n

\"a
\nA collection of 3D scans of fossil sabertooth skulls from various groups that date from very recent times (center, Smilodon populator, which disappeared around 8,000 BCE) to more than 35 million years ago. Rivaling Smilodon in the length of its upper canines was a more ancient cat-like sabertooth from the Nimravid family (3 to 5 o\u2019clock), which went extinct about 7 million years ago. The crania from more ancient lineages have shorter upper canines than those from more recent lineages, illustrating the evolutionary trend toward longer canines among all types of sabertooths. Narimane Chatar\/UC Berkeley<\/p>\n

\u201cThere was a crazy variety of saber-toothed cats,\u201d Chatar said. \u201cTaxa like\u00a0Smilodon\u00a0and\u00a0Homotherium\u00a0and other species with very long upper canines tend to attract all of the attention, but most of the early diverging species in this group actually had shorter upper canines. Unfortunately, we know more about the late-diverging species, like\u00a0Smilodon\u00a0and\u00a0Homotherium, than we know about those early-diverging ones.\u201d<\/p>\n

Chatar\u2019s PhD thesis focused on the evolution of saber-toothed animals. While conducting her research, she visited numerous museums around the world with a portable laser scanner to obtain detailed surface scans of sabertooth fossils. She later combined these scans to reconstruct precise 3D images of each. While at the American Museum, she pulled out every drawer labeled \u201cfelids\u201d or \u201ccats\u201d and noticed one cranium from Arizona labeled\u00a0Pseudaelurus\u00a0that looked suspiciously unlike modern cats.\u00a0Pseudaelurus\u00a0means \u201cfalse cat\u201d and is a \u201cwastebasket\u201d term used to label any unidentified fossil that looks like a cat, she said.<\/p>\n

\u201cI was a bit intrigued because the cranium was quite complete and had a fragmentary mandible with the whole dentition,\u201d she said. \u201cAnd in the drawer I also found upper canines. When I saw that they were laterally compressed, I knew it was not a cat or a tiger.\u201d<\/p>\n

She scanned it but forgot about it until she was at the Yale Peabody Museum in New Haven to scan a cast of the original fossil of\u00a0Adelphailurus kansensis. The original, or holotype, has been at the University of Kansas since it was discovered in 1924, though it was only described as a new species in 1934. The cast looked remarkably like the fossils at the American Museum.<\/p>\n

\"a
\nA scan of the fossil cranium of Adelphailurus kansensis unearthed in Arizona in 1939 (left) and a reconstruction of the full skull with upper canines. Narimane Chatar, J. Gamarra, AMNH<\/p>\n

After completing her thesis from the University of Liege in Belgium, Chatar moved to Berkeley and dived into other research: comparing the biting and crunching abilities of many types of carnivores, living and extinct, to determine how these abilities were correlated with tooth and skull shape. Only after that project got fully underway did she take up the \u201cside project\u201d of analyzing the\u00a0Pseudaelurus\u00a0skull. In the new paper, co-authored with Tseng, Chatar describes the features of the American Museum fossil that align with the original\u00a0Adelphailurus\u00a0fragments found in Kansas and bits of similar fossils later discovered in Nebraska, Texas and Mexico.<\/p>\n

One difference is that the snout is quite narrow and long in\u00a0Adelphailurus, she said, which is different from other saber-toothed cats from the same era. The animal\u2019s teeth also have slight serrations on the edge, which are found in some but not all sabertooths and perhaps operated like serrated knives.<\/p>\n

The shorter upper canines of the ancestral species of saber-toothed animals, including\u00a0Adelphailurus,\u00a0support Chatar\u2019s theory that once these hyper carnivores started to evolve longer fangs, they were unable to get rid of them.<\/p>\n

\"a
\nPostdoctoral fellow Narimane Chatar examining casts of sabertooth jawbones (Smilodon and Barbourofelis). Courtesy of Narimane Chatar\/UC Berkeley<\/p>\n

\u201cWe\u2019ve never found any lineage that started developing long upper canines and then stopped and went back to a less specialized state; once a group starts, they (the fangs) go crazy and then they go extinct,\u201d Chatar said. \u201cSaber-toothed carnivores are an example of something called the macroevolutionary ratchet, where basically, you start developing some super specialized morphology and you get very efficient at doing one single thing, but when the environment changes to make that thing harder \u2014 harder to find prey and hunt, for example \u2014 then you\u2019re just more likely to go extinct.\u201d<\/p>\n

Chatar\u2019s chance discovery of the\u00a0Adelphailurus\u00a0suggests that other unique and important specimens lie undiscovered in museums.<\/p>\n

\u201cIt highlights the need to go back to those old collections and open every single drawer and look at those specimens, because there might be amazing fossils like this one just hidden somewhere, labeled cat or\u00a0Pseudaelurus\u00a0or something else, that just need to be described,\u201d she said.<\/p>\n

The work was supported by grants from the U.S. National Science Foundation (NSFDBI-2128146), Belgium\u2019s Fund for Scientific Research (FC 36251) and the Belgian American Educational Foundation and by a Marie Sk\u0142odowska-Curie Actions Postdoctoral Fellowship.<\/p>\n

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