Smilodon

Smilodon Temporal range: Early Pleistocene to Early Holocene, 2.5–0.01 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Mounted S. populator skeleton at Tellus Science Museum
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Carnivora
Suborder:	Feliformia
Family:	Felidae
Subfamily:	†Machairodontinae
Tribe:	†Smilodontini
Genus:	†Smilodon Lund, 1842
Type species
†Smilodon populator Lund, 1842
Other species
†S. fatalis (Leidy, 1869) †S. gracilis Cope, 1880
Synonyms
Genus synonymy Munifelis Muñis, 1845 Trucifelis Leidy, 1868 Smilodontopsis Brown, 1908 Prosmilodon Rusconi, 1929 Smilodontidion Kraglievich, 1948 Species synonymy S. populator: Munifelis bonaerensis Muñis, 1845 Smilodon blainvillii Desmarest, 1860 Machaerodus bonaerensis Burmeister, 1867 Machaerodus necator Gervais, 1878 Smilodon ensenadensis Ameghino, 1888 Machaerodus ensenadensis Ameghino, 1889 Smilodon crucians Ameghino, 1904 Smilodon bonaerensis Ameghino, 1907 Smilodon neogaeus ensenadensis Boule & Thévenin, 1920 Smilodon (Prosmilodon) ensenadensis Rusconi, 1929 Smilodon neogaeus de Paula Couto, 1940 Smilodon necator de Paula Couto, 1940 Smilodon (Prosmilodon) ensenadensis ferox Kraglievich, 1947 Smilodon (Prosmilodon) ensenadensis minor Kraglievich, 1948 Smilodontidion riggii Kraglievich, 1948 Machaerodus neogaeus Pictet, 1953 Felis smilodon Desmarest, 1953 Smilodon populator populator de Paula Couto, 1955 S. fatalis: Felis (Trucifelis) fatalis Leidy, 1868 Trucifelis fatalis Leidy, 1869 Machaerodus fatalis Lydekker, 1884 Drepanodon floridanus Leidy, 1889 Machaerodus floridanus Leidy, 1889 Uncia mercerii Cope, 1895 Smilodon floridanus Adams, 1896 Machaerodus (Smilodon) mercerii Cope, 1899 Smilodon californicus Bovard, 1907 Smilodontopsis troglodytes Brown, 1908 Smilodontopsis conardi Brown, 1908 Smilodontopsis mercerii Brown, 1908 Smilodon nebraskensis Matthew, 1918 Machaerodus mercerii Matthew, 1918 Smilodon (Trucifelis) californicus Merriam & Stock, 1932 Smilodon (Trucifelis) fatalis Merriam & Stock, 1932 Smilodon (Trucifelis) nebraskensis Merriam & Stock, 1932 Smilodon (Trucifelis) californicus brevipes Merriam & Stock, 1932 Smilodon trinitensis Slaughter, 1960 S. gracilis: Machaerodus (Smilodon) gracilis Cope, 1899 Smilodon (Smilodontopsis) gracilis Merriam & Stock, 1932 Megantereon gracilis Broom & Schepers 1946 Ischyrosmilus gracilis Churcher, 1984 Smilodontopsis gracilis Berta, 1995

Smilodon is an extinct genus of 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 epoch (2.5 mya – 10,000 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.

In North America, Smilodon hunted large herbivores such as bison and camels, and it remained successful even when encountering new prey taxa in South America such as Macrauchenia. 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 as part of the end-Pleistocene extinction event around 13-10,000 years ago, along with most other large animals across the Americas. Its reliance on large animals has been proposed as the cause of its extinction. Smilodon may have been impacted by habitat turnover and loss of prey it specialized on due to possible climatic impacts, the effects of recently arrived humans on prey populations, and other factors.