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Fossils Reveal Why Coyotes Outlived Saber-Toothed Cats

Contrary to popular belief, carnivorous cats and canines probably didn’t hunt the same limited pool of prey

Saber-toothed cats likely ambushed plant-eating prey in forests, not open grassland (Mauricio Antón)
smithsonian.com

Saber-toothed cats are often envisioned as fierce predators stalking the open savannah in pursuit of bison, horses and other grassland-dwelling prey. But a new study published in the journal Current Biology paints a different portrait of the long-extinct Smilodon fatalis. As researchers led by Vanderbilt University’s Larisa DeSantis found, fossils recovered from the La Brea Tar Pits in California suggest the up to 600-pound cat actually preferred hunting in the forest, where easy targets, including tapirs and deer, congregated en masse.

These findings, based on an analysis of more than 700 fossil teeth belonging to multiple prehistoric species, contradict the idea that competition among carnivores drove saber-toothed cats and other megafauna to extinction some 10,000 to 12,000 years ago. For instance, most ancient canine predators, like dire wolves, stuck to the open fields.

“The cats, including saber-toothed cats, American lions and cougars, hunted prey that preferred forests, while it was the dire wolves that seemed to specialize on open-country feeders like bison and horses,” DeSantis explains in a press release. “While there may have been some overlap in what the dominant predators fed on, cats and dogs largely hunted differently from one another.”

Per CNN’s Ashley Strickland, the scientists’ research pinpoints a different explanation for S. fatalis and other giant cats’ demise, positing that factors, including climate change and an uptick in nearby human populations, precipitated the species’ eventual extinction. (The team is collaborating on a second study with experts across six institutions to further refine these causes, Chrissy Sexton notes for Earth.com.)

Smaller predators such as coyotes and grey wolves, on the other hand, weathered harsh conditions by adapting to the times. As DeSantis tells National Geographic’s John Pickrell, “When the large predators and prey go extinct, not only do [the smaller animals] shrink, but they fundamentally change their diet and start scavenging to become the opportunists we know today.”

According to Pickrell, DeSantis and her colleagues arrived at their conclusions by studying microscopic patterns of wear on fossil teeth, as well as the proportions of two carbon isotopes found within tooth enamel. These isotopes, passed along from plant-eating prey to carnivorous predators, identify victims’ preferred habitat as open versus forested environments.

Since excavations began around 100 years ago, the La Brea Tar Pits—bubbling pools of natural asphalt that attracted predators and prey alike, entrapping both within its sticky depths—have yielded more than 3.5 million specimens representing some 600 species. Most of these unlucky animals were carnivores lured in by the carcasses of horses, bison and camels already caught in the tar; rather than escaping with an easy meal, the predators soon found themselves similarly stuck.

Previously, research on the La Brea remains has focused on carbon and nitrogen isotopes found within a bone protein called collagen. These analyses all arrived at the same conclusion: Prehistoric predators from saber-toothed cats to dire wolves and American lions hunted in open environments, competing for the same limited pool of prey. But as Julie Meachen, a Des Moines University paleontologist who was not involved in the study, explains to National Geographic, tooth enamel is far more reliable than collagen, emerging from centuries underground completely intact.

“When we look at the enamel, we get a totally different picture,” DeSantis tells Pickrell. “We find that the saber-tooth cats, American lions, and cougars are actually doing what cats typically do, which is hunting within forested ecosystems and using cover to potentially ambush their prey.”

In the statement, DeSantis says the research offers new insights on the long-term consequences of giant cats’ extinction.

“The animals around today that we think of as apex predators in North America—cougars and wolves—were measly during the Pleistocene,” she concludes. “So when the big predators went extinct, as did the large prey, these smaller animals were able to take advantage of that extinction and become dominant apex-predators.”

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