Saber-toothed cats

A saber-toothed cat (alternatively spelled sabre-toothed cat) is any member of various extinct groups of predatory mammals that were characterized by long, curved saber-shaped canine teeth. The large maxillary canine teeth extended from the mouth even when it was closed. The saber-toothed cats were found worldwide from the Eocene epoch to the end of the epoch (42 mya – 11,000 years ago), existing for about 42 million years.

One of the best known genera is Smilodon, species of which, especially S. fatalis, are popularly, but incorrectly referred as a "saber-toothed tiger," a genus within the subfamily Machairodontinae of the carnivoran family Felidae. Extant members of Felidae include cats of the subfamilies Felinae and Pantherinae.

However, usage of the word cat is in some cases a misnomer, as many species referred to as saber-toothed "cats" are not closely related to modern cats of Felidae: instead, many are members of other feliform carnivoran families, such as Barbourofelidae and Nimravidae; the oxyaenid "creodont" genera Machaeroides and Apataelurus; and two lineages of metatherian mammals, the thylacosmilids of Sparassodonta, and deltatheroideans, which are more closely related to marsupials than to the placental mammals of the other orders mentioned. In this regard, saber-toothed cats 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, that is so consistent that it has been termed the "saber-tooth suite."

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