A new study of the teeth of saber-tooth cats and American lions reveals that these large carnivores did not resort to chomping on bones just before extinction, suggesting that lack of food was probably not the primary reason these large cats became extinct.
The saber-toothed cat and American lion went extinct along with other large animals approximately 12,000 years ago. Previous studies have suggested many causes of this extinction, including a changing climate, human activity and human competition for food. In the current study, researchers at Vanderbilt University discovered no difference in bone consumption between older fossils and more recent ones. Based on this evidence, they believe that the saber-tooth cats’ diet did not change significantly near the time they became extinct.
The Science Recorder took a few minutes to ask Professor Larisa DeSantis, assistant professor of earth and environmental sciences at Vanderbilt University, some questions about her new findings. Here is a transcript of our email conversation:
Science Recorder (SR): What was the motivation for this study?
Professor Larisa DeSantis (PLD): “Our primary motivation for this study was to better understand the ancient biology of these organisms in hopes that we might be able to further clarify why they went extinct. Additionally, we aimed to use a recently developed 3D dental microwear technique which often provides a more refined understanding of what these animals were eating.”
SR: Why did you decide that dental microwear texture analysis would be the best way to test the theory that saber-tooth cats went extinct due to starvation?
PLD: “In contrast to the shape of the skull and teeth which provide information about an animals potential diet, dental microwear texture analysis allows us to determine what animals were actually consuming shortly before their death. However, before even attempting this study we had to develop a baseline to make sure this method worked. That study, led by co-author Blaine Schubert from East Tennessee State University, demonstrated that observed behaviors are recorded in the dental microwear of living animals. For example, living cheetahs which avoid bone and living hyenas which actively consume and process bone show distinctly different dental microwear properties. With the knowledge that dental microwear texture analysis works in living carnivores, we applied this same method to fossil cats to better understand their ancient dietary behavior.”
SR: Do you and your research team have any theories as to why saber-tooth cats went extinct?
PLD: “While it remains difficult to discern between climate change and human overkill, we can say that these cats were living the “good life “at least until the very end. They were not desperately fully consuming carcasses at any point during the late Pleistocene at La Brea. Further work is needed to determine if this pattern is ubiquitous across different carnivores and at different sites globally. However, these two cats in addition to prior work on the dire wolf at La Brea all leads us to question the idea that times were tough and these carnivores went extinct due to lack of food.”
SR: Are you conducting any additional research on this subject?
“Currently, we are also studying the giant short faced bear and the mountain lion at La Brea. Shelly Donahue, a current graduate student at Vanderbilt University is leading the work on Artodus simus to better understand its paleobiology and why it may have gone extinct. However this work first requires an understanding of modern bear diets and how they are recorded using dental microtexture analysis. We are also examining the mountain lion both at La Brea during the Pleistocene and today in Southern California to understand how it’s diet may have changed over time and/or why it may have fared better than the other large cats. Lastly, I am leading up work on Australian marsupial carnivores to better understand their ancient diets and potential extinction implications.”
While the researchers are not sure why saber-tooth cats became extinct, they are growing more confident that they did not starve to death.
The study’s findings were published on December 26 in the open access journal PLOS ONE by Professor DeSantis and her colleagues.