Saber-toothed predator

A saber-tooth (alternatively spelled sabre-tooth) is any member of various extinct groups of predatory therapsids, predominantly carnivoran mammals, that are characterized by long, curved saber-shaped canine teeth which protruded from the mouth when closed.

Among the earliest animals that can be described as "sabertooths" are the gorgonopsids, a group of non-mammalian therapsids that lived during the Middle-Late Permian, around 270-252 million years ago (mya). Saber-toothed mammals have been found almost worldwide from the Eocene epoch to the end of the Pleistocene epoch (42 million years ago – 11,000 years ago).

One of the best-known genera is the "saber-toothed cat" Smilodon, the species of which, especially S. fatalis, are popularly referred to as "saber-toothed tigers", although they are not closely related to tigers (Panthera), and are instead members of the extinct cat subfamily Machairodontinae (the true saber-toothed cats), most members of which had saber-teeth of varying lengths. Despite some similarities, not all saber-tooths are closely related to saber-toothed cats or felids in-general. For example, many members are classified into different family of Feliformia, the Nimravidae; or from a separate order such as Machaeroides and Apataelurus, which are members of the order Oxyaenodonta, and two extinct lineages of metatherian mammals (related to marsupials), including the thylacosmilids of Sparassodonta. In this regard, these saber-toothed mammals can be viewed as examples of convergent evolution. This convergence is remarkable due not only to the development of elongated canines, but also a suite of other characteristics, such as a wide gape and bulky forelimbs, which is so consistent that it has been termed the "saber-tooth suite."

Of the feliform lineages, the family Nimravidae is the oldest, entering the landscape around 42 mya and becoming extinct by 7 mya. Both machairodonts and nimravids (specifically Barbourofelinae) would have shared some habitats.