Scientists long believed that the saber-toothed cat—or Homotherium, if you will—went extinct in Europe approximately 300,000 years ago. But a new study suggests the species may have been around hundreds of thousands of years longer, reports Andrew Masterson of Cosmos Magazine, co-existing with modern humans.
In the early 2000s, a Homotherium jawbone was trawled up from the bottom of the North Sea, and radiocarbon dating suggested the bone was far younger than expected—just 28,000 years old. Researchers debated the find, and many questioned if it was properly identified. But the latest study, published in journal Current Biology, may help quell those doubts.
A team led by Johanna Paijmans of the University of Potsdam in Germany has created a mitochondrial genome reconstruction of the Homotherium jawbone and found that the fossil did indeed belong to a saber-toothed cat. In other words, “[w]hen the first anatomically modern humans migrated to Europe, there may have been a saber-toothed cat waiting for them," Paijmans says in a press release.
The study led to a number of other tantalizing discoveries. Researchers conducted partial genome reconstructions of three Homotherium fossils from both Europe and North America, along with one Smilodon specimen from South America. The Smilodon is what most people think of when they imagine saber-toothed tigers, though the animals are not closely related. And as Rachael Lallensack explains in Nature, the Homotherium had smaller, more serrated fangs than the Smilodon.
Researchers found that Homotherium and Smilodon shared an ancestor, also common to all living cats, that lived about 20 million years ago. The prehistoric felines diverged about 18 million years ago. According to Michelle Z. Donahue of National Geographic, the study also revealed that there were very few genetic differences between the European and North American Homotherium—so few, in fact, that researchers say they should no longer be classified as distinct species.
It isn’t clear how animals living on two different continents could be so genetically similar. Nor do researchers know why Homotherium bones suddenly appear in the fossil record 200,000 years after they appeared to die out in Europe. But as Lallensack notes, migration of the ancient cats could be the answer to these lingering questions. “The North Sea specimen could be evidence that the cats migrated back into Western Europe from Asia or over the Bering land bridge from North America,” she writes.
The new timeline for the Homotherium may also explain its eventual disappearance. It is possible that cats were driven to extinction by the Ice Age, during which many species perished due to harsh climate conditions. Or, as Jen Viegas notes in Seeker, anatomically modern humans migrating from Africa may have simply wiped them out.