Smilodon of sabeltandtijger is een geslacht van aan het eind van het Pleistoceen uitgestorven grote carnivoren uit de familie van de katachtigen (Felidae). Ondanks de naam sabeltandtijger is Smilodon niet direct verwant met de tijger. Smilodon leefde in Noord-, Midden- en Zuid-Amerika. Ze leefden op grasland en in niet al te dicht begroeide bossen. De botten van veel exemplaren zijn in de teerputten van La Brea gevonden, zodat er vrij veel over ze bekend is. De in Europa levende Homotherium latidens wordt ook sabeltandtijger genoemd. Deze soort is wel een lid van dezelfde onderfamilie maar wordt in een andere geslachtengroep (Homotheriini) geplaatst. Smilodon behoorde tot een groep katachtigen die de sabeltandkatten (Machairodontinae) worden genoemd. Het geslacht stamde af van Paramachairodus (13 tot 2 miljoen jaar geleden). Ook dit geslacht wordt meestal tot de sabeltandtijgers gerekend. Smilodon was niet nauw verwant aan tijgers en is geen voorouder van enige nog levende grote kattensoort. Het is nog onduidelijk waardoor Smilodon is uitgestorven. ...

Smilodon populator es un specie extincte in le familia del Felidae.

Smilodon is a genus of the extinct machairodont subfamily of the felids. It is one of the best known saber-toothed predators and one of the most famous prehistoric mammals....

The Felidae are known in South America from the Ensenadan Stage/Age onwards. Among them, machairodonts of the genus Smilodon stand out. Three species are recognized, and all three are present on the continent: S. gracilis from the early-middle Pleistocene in north-east Venezuela; S. fatalis, found only in Lujanian sediments on the west side of the Andes (north-west of Peru and south-west of Ecuador); and S. populator, which inhabited the eastern part of the Andes during the Ensenadan and Lujanian. This distribution has led to the suggestion that the last two felids were allopatric during the Lujanian. Here, we report the first evidence of S. fatalis in the eastern part of the continent (Sopas Formation, late Pleistocene of Uruguay), based on an almost complete skull. This finding not only enlarges its distribution in South America but questions the idea of allopatric distribution. It also adds a new component to the mammalian predator trophic level of Uruguay, with the capacity to predate large South American herbivores and megaherbivores. A revision of materials previously assigned to S. populator in the extra-Andean zone of South America will be required.

Skeletal disease may hamper the behavior of large predators both living and extinct. We investigated the prevalence of osteochondrosis dissecans (OCD), a developmental bone disease affecting the joints, in two Ice Age predators: the saber-toothed cat Smilodon fatalis and dire wolf Aenocyon dirus. As published cases in modern Felidae and wild Canidae are rare, we predicted that subchondral defects resembling OCD would be rare in the extinct predators. We examined limb joints in juvenile and adult S. fatalis: 88 proximal humeri (shoulder), 834 distal femora (stifle), and 214 proximal tibiae. We also examined limb joints in juvenile and adult A. dirus: 242 proximal humeri, 266 distal femora, and 170 proximal tibiae. All specimens are from the Late Pleistocene Rancho La Brea fossil locality in Los Angeles, California, USA. While the Smilodon shoulder and tibia showed no subchondral defects, subchondral defects in the Smilodon femur had a prevalence of 6%; most defects were small (<7mm); and nine adult stifles with defects also showed osteoarthritis. Subchondral defects in the A. dirus femur had a prevalence of 2.6%; most defects were large (>12mm); and five stifles further developed mild osteoarthritis. Subchondral defects in the A. dirus shoulder had a prevalence of 4.5%; most defects were small, and three shoulders developed moderate osteoarthritis. No defects were found in the A. dirus tibia. Contrary to our prediction, we found a high prevalence of subchondral defects in the stifle and shoulder of S. fatalis and A. dirus resembling OCD found in humans and other mammals. As modern dogs affected by OCD are highly inbred, this high prevalence in the fossil taxa may suggest that they experienced inbreeding as they approached extinction. The deep-time history of this disease supports the need for monitoring of animal domestication, as well as conservation, to avoid unexpected surges in OCD under conditions like inbreeding.