The Saber tooth tiger is approximately the size of a modern tiger or lion.Saber-toothed cats did not go extinct for lack of prey fossil evidence now proves,even near their extinction, saber-toothed cats had enough to eat, researchers said.Saber-toothed cats, American lions, woolly mammoths and other giant animals once roamed across the America. But about 12,000 years ago, these animals went extinct, a die-off called the Quaternary extinction.