Saber-toothed cats did not starve to death, say researchers

December 27, 2012

Saber-toothed cats did not starve to death, say researchers

Researchers at Vanderbilt University have found evidence suggesting that saber-toothed cats were not driven to extinction due to starvation.

Researchers at Vanderbilt University say they have found evidence that saber-toothed cats did not starve to death. They believe that the American lions and saber-toothed cats that roamed North America in the late Pleistocene had plenty of food to eat.

According to the Cleveland Museum of Natural History, Danish paleontologist Peter Wilhelm Lund was the first person to describe the Saber-toothed cat from fossils he found in a cave in Lagoa Santa, Brazil, in 1842. While the public typically thinks of the saber-toothed cat as a bloodthirsty tiger, the prehistoric cat has more in common with today’s modern African lion.

After examining microscopic wear patterns on the teeth of saber-toothed cats recovered from the La Brea tar pits in Southern California, researchers concluded that starvation did not lead to their extinction. Previous studies have argued that the large cats were having trouble locating prey in the period before they disappeared 12,000 years ago. However, this study found no evidence to suggest that saber-toothed cats could not find food.

Researchers believe that their  findings present a major problem for the most popular explanations for the Megafaunal extinction.

“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,” said Larisa DeSantis, assistant professor of earth and environmental sciences at Vanderbilt, in a statement. “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. 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.”

In 1993, Blaire Van Valkenburgh at University of California Los Angeles analyzed the teeth of American lions, saber-toothed cats, wolves and coyotes recovered from La Brea. She discovered that these mammals had approximately three times as many broken teeth as contemporary predators.

“These findings suggest that these species utilized carcasses more fully and likely competed more intensely for food than present-day large carnivores,” she wrote in a paper at the time.

Researchers utilized a new technique, called dental microwear texture analysis (DMTA), to examine the teeth of saber-toothed cats. DMTA uses a confocal microscope to generate a 3D image of the surface of a tooth. The image can then be examined for microscopic wear patterns, such as small parallel scratches (patterns produced by the consumption of red meat) and deeper pits (patterns produced by consumption of bones). Researchers consider DMTA more accurate because it relies on automated software.

Researchers used DMTA to examine the fossil teeth of 15 American lions and 15 saber-toothed cats recovered from the La Brea tar pits. Researchers discovered that the wear pattern on the teeth of the American lion was very similar to those of the present-day cheetah. They also found that the saber-toothed cat’s wear pattern looked a lot like those of the present-day African lion (which will sometimes chomp on bones when it consumes an animal).

Researchers learned that neither American lions nor saber-toothed cats maximized their consumption of carcasses during a period of 35,000 to 11,500 years ago. Their findings suggest that the proportion of the carcasses that both carnivores ate declined toward the end of this period.

Researchers think that the high rate of tooth breakage reported in the 1993 study is probably a result of the animals trying to bring down prey.

“Teeth can break from the stress of chewing bone but they can also break when the carnivores take down prey,” Ms. DeSantis said.

The cheetah, for instance, which is more likely break canines than rear teeth, does not chomp on bones during feedings. The researchers note that previous examinations of the jaws of saber-toothed cats from this period revealed that they have more than three times as many broken canines. This is evidence, researchers contend, that saber-toothed cats primarily broke their teeth while capturing prey.

Researchers also point out that the extinct carnivores and their prey were much larger than today’s mammals. The saber-toothed cats, which were approximately the size of today’s African lions, had to capture mammoths and bison. The large teeth of these big carnivores were more likely to break than smaller teeth.

“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,” Ms. 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.”

The study’s findings were recently published in the journal PLOS ONE.


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