Animals sporting elongated curved canine teeth have appeared twice in the fossil record, millions of years apart. One lineage, the nimravids, went extinct about in North America about 23 million years ago. Then the saber-toothed tiger vanished about 8,000 years to 10,000 years ago. More recently, saber teeth have also evolved in “true” cats of the Felidae family.
Scientists have long wondered why saber teeth emerged over different times and places, vanished, then re-appeared. A new study in Current Biology fills in some evolutionary gaps.
