The oldest known saber-toothed predator, dating back over 270 million years ago, appears to have been an animal caught in the evolutionary middle, according to a report in Nature Communications.
The gorgonopsian excavated in Mallorca laid eggs, unlike most mammals. But it was warm-blooded, unlike reptiles. Its leg shape and position were halfway between mammal and reptile. And its saber teeth were more commonly associated with mammals like Smilodon, which emerged in North America about 2.5 million years ago. It looked sort of like a 3-foot-long dog — but without ears or fur.