<P> Smilodon is a genus of the extinct machairodont subfamily of the felids . It is one of the most famous prehistoric mammals, and the best known saber - toothed cat . Although commonly known as the saber - toothed tiger, it was not closely related to the tiger or other modern cats . Smilodon lived in the Americas during the Pleistocene epoch (2.5 mya--10,000 years ago). The genus was named in 1842, based on fossils from Brazil . 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 largest collection of Smilodon fossils has been obtained from the Rancho La Brea Tar Pits in Los Angeles, California . </P> <P> 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 (120 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 . S. populator from South America was the largest species, at 220 to 400 kg (490 to 880 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 . </P> <P> In North America, Smilodon hunted large herbivores such as bison and camels, and it remained successful even when encountering new prey species in South America . Smilodon is thought to have killed its prey by holding it still with its forelimbs and biting it, but it is unclear in what manner the bite itself was delivered . Scientists debate whether Smilodon had a social or a solitary lifestyle; analysis of modern predator behavior as well as of Smilodon's fossil remains could be construed to lend support to either view . Smilodon probably lived in closed habitats such as forests and bush, which would have provided cover for ambushing prey . Smilodon died out at the same time that most North and South American megafauna disappeared, about 10,000 years ago . Its reliance on large animals has been proposed as the cause of its extinction, along with climate change and competition with other species, but the exact cause is unknown . </P> <P> During the 1830s, Danish naturalist Peter Wilhelm Lund and his assistants collected fossils in the calcareous caves near the small town of Lagoa Santa, Minas Gerais, Brazil . Among the thousands of fossils found, he recognized a few isolated cheek teeth as belonging to a hyena, which he named Hyaena neogaea in 1839 . After more material was found (including canine teeth and foot bones), Lund concluded the fossils instead belonged to a distinct genus of felid, though transitional to the hyenas . He stated it would have matched the largest modern predators in size, and was more robust than any modern cat . Lund originally wanted to name the new genus Hyaenodon, but realizing this had recently become preoccupied by another prehistoric predator, he instead named it Smilodon populator in 1842 . He explained the Ancient Greek meaning of Smilodon as σμίλη (smilē), a scalpel or two - edged knife, and οδόντος (odontús), tooth . This has also been translated as "tooth shaped like double - edged knife". He explained the species name populator as "the destroyer", which has also been translated as "he who brings devastation". By 1846, Lund had acquired nearly every part of the skeleton (from different individuals), and more specimens were found in neighboring countries by other collectors in the following years . Though some later authors used Lund's original species name neogaea instead of populator, it is now considered an invalid nomen nudum ("naked name"), as it was not accompanied with a proper description and no type specimens were designated . Some South American specimens have been referred to other genera, subgenera, species, and subspecies, such as Smilodontidion riggii, Smilodon (Prosmilodon) ensenadensis, and S. bonaeriensis, but these are now thought to be junior synonyms of S. populator . </P>

When did the sabre tooth tiger became extinct