The famous saber-tooth cat that lived in North America beginning about 2 million years ago survived by ambushing prey such as camels and ground sloths before sinking its 7-inch fangs into their flesh. And yet, these enormous daggers actually may have been the Smilodon fatalis’ downfall.
For a new study published in the Journal of Vertebrate Paleontology, University of California, Berkeley postdoc Narimane Chatar took a closer look at an old animal skull from Arizona housed in the museum collections at the American Museum of Natural History. Although it was tagged only as a “feline,” its flattened teeth caught her attention. “In the drawer I also found upper canines,” explained Chatar in a press release. “When I saw that they were laterally compressed, I knew it was not a cat or a tiger.”
After creating a 3-D reconstruction of the entire skull, Chatar discovered its strong resemblance to a specimen found in Kansas in 1924. The long, narrow snout and serrated-edge teeth on both specimens united them as Adelphailurus kansensis, a puma-sized cat that inhabited western North America more than 5 million years ago. At about an inch long, its fangs were much shorter than those of the iconic S. fatalis but could still likely cut through flesh like a blade.
Read more: “The Mystery of the Cave Cats”
“Back in the days when we thought about saber-tooths, we thought ‘Smilodon,’ and that’s it. We thought that all species that exhibited a somewhat saber-like tooth morphology must have hunted like Smilodon and behaved like Smilodon,” said Chatar.
But in comparing A. kansensis to a range of other saber-tooth cats known from fossils, Chatar placed it in the family tree, finding that most of the earlier species had shorter upper canines as well. Longer canines came later during the evolution of saber-toothed cats, culminating in the imposing fangs of S. fatalis.
Saber-shaped teeth, however, aren’t as sturdy as the rounded teeth of modern cats, according to another study coauthored by Chatar. While they’re optimized for puncturing the necks or torsos of prey, saber teeth break more easily, which may explain the demise of S. fatalis about 10,000 years ago. Chatar describes the evolution of saber-tooth cats as a “macroevolutionary ratchet.” That is, they became super specialized at one thing—killing large prey—at the expense of other adaptations. And so, when ground sloths and camels died out about 13,000 years ago as the ice age waned, S. fatalis failed to find other meals.
“When the environment changes to make that thing harder—harder to find prey and hunt, for example—then you’re just more likely to go extinct,” said Chatar.
There may be no greater example of how a strength can become a weakness.
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Lead image: Daniel Eskridge / Adobe Stock
