Homotherium may have lived and hunted in groups
The first in-depth study of saber-toothed cat DNA reveals genetic evidence that some of them were fast-moving predators that lived in social groups.
Ross Barnett of the University of Copenhagen in Denmark and his colleagues focused on Homotherium latidens, sometimes referred to as the scimitar tooth cat because its canine teeth were slightly shorter than many members of this group of extinct cats.
Given the proportions of its fossil bones, researchers have long suspected that Homotherium was chasing after its prey rather than waiting in ambush. Barnett and his colleagues discovered evidence of the idea in genetic clues obtained from a homotherium femur discovered in Canada's Yukon region, which is at least 47,000 years old.
The cat's DNA shows that the ancestors of Homotherium separated from other groups of cats about 22.5 million years ago. It also includes genes linked to activity during the day, as well as adaptations in the respiratory and circulatory systems related to running. Saber-toothed cats also have thick, strong bones on their front limbs for grabbing prey, says University of Toronto paleontologist Ashley Reynolds. "So it's very interesting to see positive selection in PID, a gene that is associated with bone mineralization."
Barnett and colleagues also found genes linked to social behavior, suggesting that Homotherium may have lived in groups like lions instead of living and hunting alone like a leopard. In addition, the genetic diversity in the sample suggests that Homotherium was far more common than previously thought. "Given the extremely low number of Homotherium fossils, this was a shock," says Barnett.
This may mean that many unidentified saber-tooth cat bones in museum collections really belong to Homotherium. "The skull and teeth are easier to see than the rest of the body," says Reynolds.
The study itself underscores this possibility. “Indeed,” says Barnett, “this homotherium bone was first called the“ big cat / cave lion? "Identified before we got the DNA."
Journal reference: Current Biology, DOI: 10.1016 / j.cub.2020.09.051
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