[credit provider=”Larisa DeSantis / Vanderbilt University” url=”http://www.eurekalert.org/pub_releases/2012-12/vu-eci121812.php”]
The saber-toothed cat and American lion were some of the largest terrestrial carnivores in North America about 12,000 years ago. The cause of their extinction is debated among researchers, but a new study suggests they didn’t starve to death.”The popular theory for the Megafaunal extinction is that either the changing climate at the end of the last Ice Age or human activity — or some combination of the two — killed off most of the large mammals,” study researcher Larisa DeSantis, of Vanderbilt University, said in a press release.
She sums up the case researchers usually make: “In the case of the great cats, we expect that it would have been increasingly difficult for them to find prey, especially if had to compete with humans,” she said. “We know that when food becomes scarce, carnivores like the great cats tend to consume more of the carcasses they kill. If they spent more time chomping on bones, it should cause detectable changes in the wear patterns on their teeth.”
The research published today, Dec. 26, by Plos One analysed the texture and micro-wear of the fossilized teeth of 15 American lions (Panthera atrox) and 15 saber-tooth cats (Smilodon fatalis), to see if that was indeed the case. Some of the fossils were up to 35,000 years old, while some were from the end of the species’ reign, about 11,000 years old. If these animals were starving, then the researchers should see more wear and tooth breakage near the end of their time on Earth.
The problem: that isn’t what they found. The animals’ tooth wear or breakage didn’t fit the pattern they were expecting, suggesting that the lack of food was not the reason they went extinct.
“The net result of our study is to raise questions about the reigning hypothesis that “tough times” during the late Pleistocene contributed to the gradual extinction of large carnivores,” DeSantis said.
“While we can not determine the exact cause of their demise, it is unlikely that the extinction of these cats was a result of gradually declining prey (due either to changing climates or human competition) because their teeth tell us that these cats were not desperately consuming entire carcasses, as we had expected, and instead seemed to be living the ‘good life’ during the late Pleistocene, at least up until the very end.”