Smilodon is a genus of extinct felids. It is one of the best-known saber-toothed predators and prehistoric mammals. Although commonly known as the saber-toothed tiger, it was not closely related to the tiger or other modern cats, belonging to the extinct subfamily Machairodontinae, with an estimated date of divergence from the ancestor of living cats around 20 million years ago. Smilodon was one of the last surviving machairodonts alongside Homotherium. Smilodon lived in the Americas during the Pleistocene to early Holocene epoch (2.5 mya – at latest 8,200 years ago). The genus was named in 1842 based on fossils from Brazil; the generic name means 'scalpel' or 'two-edged knife' combined with 'tooth'. Three species are recognized today: S. gracilis, S. fatalis, and S. populator. The two latter species were probably descended from S. gracilis, which itself probably evolved from Megantereon. The hundreds of specimens obtained from the La Brea Tar Pits in Los Angeles constitute the largest collection of Smilodon fossils.
Overall, Smilodon was more robustly built than any extant cat, with particularly well-developed forelimbs and exceptionally long upper canine teeth. Its jaw had a bigger gape than that of modern cats, and its upper canines were slender and fragile, being adapted for precision killing. S. gracilis was the smallest species at 55 to 100 kg (121 to 220 lb) in weight. S. fatalis had a weight of 160 to 280 kg (350 to 620 lb) and height of 100 cm (39 in). Both of these species are mainly known from North America, but remains from South America have also been attributed to them (primarily from the northwest of the continent). S. populator from South America was the largest species, at 220 to 436 kg (485 to 961 lb) in weight and 120 cm (47 in) in height, and was among the largest known felids. The coat pattern of Smilodon is unknown, but it has been artistically restored with plain or spotted patterns.
