View source for Smilodon

{{short description|Extinct genus of saber-toothed cat}}
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{{Use American English|date = September 2019}}
{{featured article}}
{{Automatic taxobox
| fossil_range = Early [[Pleistocene]] to Early [[Holocene]], {{Geological range|2.5|0.01}}
| image = Smilodon populator fossil, Tellus Science Museum 1.jpg
| image_caption = Mounted ''S. populator'' skeleton at [[Tellus Science Museum]]
| taxon = Smilodon
| authority = [[Peter Wilhelm Lund|Lund]], 1842
| type_species = {{extinct}}'''''Smilodon populator'''''
| type_species_authority = [[Peter Wilhelm Lund|Lund]], 1842
| subdivision_ranks = Other species
| subdivision =
* {{extinct}}'''''S. fatalis''''' {{small|([[Joseph Leidy|Leidy]], 1869)}}
* {{extinct}}'''''S. gracilis''''' {{small|[[Edward Drinker Cope|Cope]], 1880}}
|synonyms =
{{collapsible list|bullets=true|title=Genus synonymy
|''Munifelis'' {{small|Muñis, 1845}}
|''Trucifelis'' {{small|Leidy, 1868}}
|''Smilodontopsis'' {{small|Brown, 1908}}
|''Prosmilodon'' {{small|Rusconi, 1929}}
|''Smilodontidion'' {{small|Kraglievich, 1948}}
}}
{{collapsible list|bullets=true|title=Species synonymy
|{{collapsible list|bullets=true|title=''S. populator'':
|''Munifelis bonaerensis'' {{small|Muñis, 1845}}
|''Smilodon blainvillii'' {{small|Desmarest, 1860}}
|''Machaerodus bonaerensis'' {{small|Burmeister, 1867}}
|''Machaerodus necator'' {{small|Gervais, 1878}}
|''Smilodon ensenadensis'' {{small|Ameghino, 1888}}
|''Machaerodus ensenadensis'' {{small|Ameghino, 1889}}
|''Smilodon crucians'' {{small|Ameghino, 1904}}
|''Smilodon bonaerensis'' {{small|Ameghino, 1907}}
|''Smilodon neogaeus ensenadensis'' {{small|Boule & Thévenin, 1920}}
|''Smilodon'' (''Prosmilodon'') ''ensenadensis'' {{small|Rusconi, 1929}}
|''Smilodon neogaeus'' {{small|de Paula Couto, 1940}}
|''Smilodon necator'' {{small|de Paula Couto, 1940}}
|''Smilodon'' (''Prosmilodon'') ''ensenadensis ferox'' {{small|Kraglievich, 1947}}
|''Smilodon'' (''Prosmilodon'') ''ensenadensis minor'' {{small|Kraglievich, 1948}}
|''Smilodontidion riggii'' {{small|Kraglievich, 1948}}
|''Machaerodus neogaeus'' {{small|Pictet, 1953}}
|''Felis smilodon'' {{small|Desmarest, 1953}}
|''Smilodon populator populator'' {{small|de Paula Couto, 1955}}
}}
|{{collapsible list|bullets=true|title=''S. fatalis'':
|''Felis'' (''Trucifelis'') ''fatalis'' {{small|Leidy, 1868}}
|''Trucifelis fatalis'' {{small|Leidy, 1869}}
|''Machaerodus fatalis'' {{small|Lydekker, 1884}}
|''Drepanodon floridanus'' {{small|Leidy, 1889}}
|''Machaerodus floridanus'' {{small|Leidy, 1889}}
|''Uncia mercerii'' {{small|Cope, 1895}}
|''Smilodon floridanus'' {{small|Adams, 1896}}
|''Machaerodus'' (''Smilodon'') ''mercerii'' {{small|Cope, 1899}}
|''Smilodon californicus'' {{small|Bovard, 1907}}
|''Smilodontopsis troglodytes'' {{small|Brown, 1908}}
|''Smilodontopsis conardi'' {{small|Brown, 1908}}
|''Smilodontopsis mercerii'' {{small|Brown, 1908}}
|''Smilodon nebraskensis'' {{small|Matthew, 1918}}
|''Machaerodus mercerii'' {{small|Matthew, 1918}}
|''Smilodon'' (''Trucifelis'') ''californicus'' {{small|Merriam & Stock, 1932}}
|''Smilodon'' (''Trucifelis'') ''fatalis'' {{small|Merriam & Stock, 1932}}
|''Smilodon'' (''Trucifelis'') ''nebraskensis'' {{small|Merriam & Stock, 1932}}
|''Smilodon'' (''Trucifelis'') ''californicus brevipes'' {{small|Merriam & Stock, 1932}}
|''Smilodon trinitensis'' {{small|Slaughter, 1960}}
}}
|{{collapsible list|bullets=true|title=''S. gracilis'':
|''Machaerodus'' (''Smilodon'') ''gracilis'' {{small|Cope, 1899}}
|''Smilodon'' (''Smilodontopsis'') ''gracilis'' {{small|Merriam & Stock, 1932}}
|''Megantereon gracilis'' {{small|Broom & Schepers 1946}}
|''Ischyrosmilus gracilis'' {{small|Churcher, 1984}}
|''Smilodontopsis gracilis'' {{small|Berta, 1995}}
}}
}}
}}
'''''Smilodon''''' is an extinct [[genus]] of [[Felidae|felids]]. It is one of the best known [[saber-toothed predator]]s 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 [[Speciation|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 [[Year#mya|mya]] – 10,000 years ago). The genus was named in 1842 based on [[fossil]]s 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 [[Neontology|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 {{cvt|55|to|100|kg}} in weight. ''S. fatalis'' had a weight of {{cvt|160|to|280|kg}} and height of {{cvt|100|cm}}. 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.&nbsp;populator'' from South America was the largest species, at {{cvt|220|to|436|kg}} in weight and {{cvt|120|cm}} in height, and was among the largest known felids. The [[Coat (animal)|coat]] pattern of ''Smilodon'' is unknown, but it has been [[paleoart|artistically restored]] with plain or spotted patterns.
In North America, ''Smilodon'' [[predation|hunted]] large [[herbivore]]s such as [[Bison antiquus|bison]] and [[Camelops|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 [[Shrubland|bush]], which would have provided cover for ambushing prey. ''Smilodon'' died out as part of the [[Late Pleistocene extinctions|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 [[Paleo-Indians|recently arrived humans]] on prey populations, and other factors.
== Taxonomy ==
{{multiple image |align = left |direction = horizontal |total_width = 400
|image1 = Smilodon populator mandible collected by Lund.jpg
|alt1 =
|image2 = Smilodon populator skull in the Zoological Museum of Copenhagen.jpg
|alt2 =
|footer = ''S. populator'' mandible collected by [[Peter Wilhelm Lund|Lund]] who described the species (left) and [[canine tooth]] from Lund's collection (right) next to a later found skull, [[Natural History Museum of Denmark]]
}}
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 [[incisor teeth]] and foot bones), Lund concluded the fossils instead belonged to a distinct genus of felids, 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 call the new genus ''[[Hyaenodon]]'', but realizing this name had recently been applied to another prehistoric predator, he instead named it ''Smilodon populator'' in 1842. He explained the [[Ancient Greek]] meaning of ''Smilodon'' as {{lang|grc|σμίλη}} (''smilē''), "scalpel" or "two-edged knife", and ''οδόντος'' (''odo&#x301;ntos''), "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". Lund based the name on the shape of the incisors, and the large [[canine teeth]] were not known until 1846. 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.{{Sfn|Antón|2013|pp=3–26}}<ref>{{cite book |last=Lund |first=P. W. |year=1842 |title=Blik paa Brasiliens Dyreverden för sidste Jordomvæltning |trans-title=Look at Brazil's animal world before the last earth upheaval |language=da |publisher=Det Kongelige Danske Videnskabernes Selskabs Naturvidenskabelige og Matematiske Afhandlinger |location=Copenhagen |pages=54–57 |url={{google books|plainurl=yes|id=4MkQAAAAIAAJ}}}}</ref><ref name="Iconic">{{cite book|last1=McDonald |first1=H. Gregory |title=''Smilodon'': The Iconic Sabertooth |chapter=''Smilodon'': a short history of becoming the iconic sabertooth |date=2018 |editor-last1=Werdelin |editor-first1=L. |editor-last2=McDonald |editor-first2=H. G. |editor-last3=Shaw |editor-first3=C. A. |publisher=Johns Hopkins University Press |location=Baltimore |isbn=9781421425573 |pages=1–11 |url=https://muse.jhu.edu/book/58589}}</ref> Though some later authors used Lund's original species name ''neogaea'' instead of ''populator'', it is now considered an invalid ''[[nomen nudum]]'', as it was not accompanied with a proper [[species description|description]] and no type specimens were designated.<ref name="Status" /> Some South American specimens have been referred to other genera, subgenera, species, and [[subspecies]], such as ''Smilodontidion riggii'', ''Smilodon'' (''Prosmilodon'') ''ensenadensis'', and ''S.&nbsp;bonaeriensis'', but these are now thought to be [[Synonym (taxonomy)#Zoology|junior synonyms]] of ''S.&nbsp;populator''.{{Sfn|Antón|2013|pp=108–154}}
[[File:Smilodon fatalis holotype.jpg|thumb|1869 [[lithograph]] of the [[holotype]] molar and maxilla fragment of ''S. fatalis'']]
Fossils of ''Smilodon'' were discovered in North America from the second half of the 19th century onwards.{{Sfn|Antón|2013|pp=3–26}} In 1869, American paleontologist [[Joseph Leidy]] described a [[maxilla]] fragment with a [[molar (tooth)|molar]], which had been discovered in a petroleum bed in [[Hardin County, Texas]]. He referred the specimen to the genus ''[[Felis]]'' (which was then used for most cats, extant as well as extinct) but found it distinct enough to be part of its own [[subgenus]], as ''F.'' (''Trucifelis'') ''fatalis''.<ref>{{cite journal |last=Leidy |first=J. |year=1869 |title=The extinct mammalian fauna of Dakota and Nebraska: Including an account of some allied forms from other localities, together with a synopsis of the mammalian remains of North America |journal=Journal of the Academy of Natural Sciences of Philadelphia |doi=10.5962/bhl.title.20910 |volume=7 |pages=366–367 |url=https://www.biodiversitylibrary.org/item/60918#page/372/mode/1up|doi-access=free }}</ref> The species name means "deadly".<ref>{{cite web|title=Sabertooth |date=21 September 2011 |publisher=National Geographic |url=https://www.nationalgeographic.org/media/sabertooth/ |access-date=2021-10-13}}</ref> In an 1880 article about extinct American cats, American paleontologist [[Edward Drinker Cope]] pointed out that the ''F.&nbsp;fatalis'' molar was identical to that of ''Smilodon'', and he proposed the [[new combination]] ''S.&nbsp;fatalis''.<ref name="Cope" /> Most North American finds were scanty until excavations began in the [[La Brea Tar Pits]] in [[Los Angeles]], where hundreds of individuals of ''S.&nbsp;fatalis'' have been found since 1875.{{Sfn|Antón|2013|pp=3–26}} ''S.&nbsp;fatalis'' has junior synonyms such as ''S.&nbsp;mercerii'', ''S.&nbsp;floridanus'', and ''S.&nbsp;californicus''.{{Sfn|Antón|2013|pp=108–154}} American paleontologist Annalisa Berta considered the holotype of ''S.&nbsp;fatalis'' too incomplete to be an adequate type specimen, and the species has at times been proposed to be a junior synonym of ''S.&nbsp;populator''.<ref name="Status">{{cite journal |last=Berta |first=A. |year=1985 |title=The status of ''Smilodon'' in North and South America |journal=Contributions in Science, Natural History Museum of Los Angeles County |volume=370 |pages=1–15 |url=http://www.nhm.org/site/sites/default/files/pdf/contrib_science/CS370.pdf|archive-url=https://web.archive.org/web/20140528023417/http://www.nhm.org/site/sites/default/files/pdf/contrib_science/CS370.pdf|archive-date=28 May 2014}}</ref> Nordic paleontologists [[Björn Kurtén]] and [[Lars Werdelin]] supported the distinctness of the two species in an article published in 1990.<ref name=Kurten /> A 2018 article by the American paleontologist John P. Babiarz and colleagues concluded that ''S. californicus'', represented by the specimens from the La Brea Tar Pits, was a distinct species from ''S. fatalis'' after all and that more research is needed to clarify the taxonomy of the lineage.<ref>{{cite book |last1=Babiarz |first1=J. P. |last2=Todd Wheeler |first2=H. |last3=Knight |first3=J. L. |last4=Martin |first4=L. D. |title=''Smilodon'': The Iconic Sabertooth |editor-last1=Werdelin |editor-first1=L. |editor-last2=McDonald |editor-first2=H. G. |editor-last3=Shaw |editor-first3=C. A. |date=2018 |publisher=Johns Hopkins University Press |location=Baltimore |isbn=978-1-4214-2557-3 |pages=76–95 |chapter=''Smilodon'' from South Carolina: Implications for the taxonomy of the genus |url=https://muse.jhu.edu/chapter/2105166 |language=en}}</ref>
In his 1880 article about extinct cats, Cope also named a third species of ''Smilodon'', ''S.&nbsp;gracilis''. The species was based on a partial canine, which had been obtained in the [[Port Kennedy Bone Cave|Port Kennedy Cave]] near the [[Schuylkill River]] in Pennsylvania. Cope found the canine to be distinct from that of the other ''Smilodon'' species due to its smaller size and more compressed base.<ref name="Cope">{{cite journal |last=Cope |first=E. D. |author-link=Edward Drinker Cope |date=December 1880 |title=On the extinct cats of America |journal=The American Naturalist |jstor=2449549 |doi=10.1086/272672 |volume=14 |issue=12 |pages=833–858|doi-access=free }}</ref> Its [[Specific name (zoology)|specific name]] refers to the species' lighter build.<ref>{{cite book |last1=Kurtén |first1=B. |last2=Anderson |first2=E. |year=1980 |title=Pleistocene Mammals of North America |publisher=Columbia University Press |isbn=978-0-231-03733-4 |location=New York |pages=186–188 |url=https://archive.org/details/pleistocenemamma0000kurt/page/186/mode/1up}}</ref> This species is known from fewer and less complete remains than the other members of the genus.<ref>{{cite journal |last=Berta |first=A. |year=1987 |title=The sabercat ''Smilodon gracilis'' from Florida and a discussion of its relationships (Mammalia, Felidae, Smilodontini) |journal=Bulletin of the Florida State Museum |volume=31 |pages=1–63 |url=http://ufdc.ufl.edu/UF00095816/00001/1j}}</ref> ''S.&nbsp;gracilis'' has at times been considered part of genera such as ''[[Megantereon]]'' and ''[[Ischyrosmilus]]''.<ref>{{Cite journal |last=Churcher |first=C. S. |year=1984 |title=The status of ''Smilodontopsis'' (Brown, 1908) and ''Ischyrosmilus'' (Merriam, 1918): a taxonomic review of two genera of sabretooth cats (Felidae, Machairodontinae) |journal=Royal Ontario Museum Life Sciences Contributions |isbn=978-0-88854-305-9 |doi=10.5962/bhl.title.52222 |volume=140 |pages=[https://archive.org/details/statusofsmilodon00chur/page/14 14–34] |url=https://archive.org/details/statusofsmilodon00chur/page/14 |doi-access=free }}</ref> ''S.&nbsp;populator'', ''S.&nbsp;fatalis'' and ''S.&nbsp;gracilis'' are currently considered the only valid species of ''Smilodon'', and features used to define most of their junior synonyms have been dismissed as variation between individuals of the same species (intraspecific variation).{{Sfn|Antón|2013|pp=108–154}}<ref name="Status" /> One of the most famous of prehistoric mammals, ''Smilodon'' has often been featured in popular media and is the [[state fossil]] of California.{{Sfn|Antón|2013|pp=3–26}}
=== Evolution ===
[[File:Smilodon gracilis skull ANSP 44.1 (2).jpg|thumb|Partial skull of ''S. gracilis'', the earliest species in the [[genus]], [[Academy of Natural Sciences of Philadelphia]]]]
[[File:Smilodon californicus mount.jpg|thumb|right|''S. fatalis'' skeleton at [[National Museum of Natural History]]]]
[[File:Säbelzahnkatze, Tierpark Berlin, 500-606.jpg|thumb|right|''S. populator'' statue in [[Tierpark Berlin]] ]]
Long the most completely known [[Machairodontinae|saber-toothed cat]], ''Smilodon'' is still one of the best-known members of the group, to the point where the two concepts have been confused. The term "[[Saber-toothed predator|saber-tooth]]" itself refers to an [[ecomorph]] consisting of various groups of extinct predatory [[synapsid]]s (mammals and close relatives), which [[convergently evolved]] extremely long [[maxillary canine]]s, as well as adaptations to the skull and skeleton related to their use. This includes members of [[Gorgonopsia]], [[Thylacosmilidae]], [[Machaeroidinae]], [[Nimravidae]], [[Barbourofelidae]], and [[Machairodontinae]].{{Sfn|Antón|2013|pp=3–26}}<ref>{{cite journal |last1=Meehan |first1=T. J. |last2=Martin |first2=L. D. |year=2003 |title=Extinction and re-evolution of similar adaptive types (ecomorphs) in Cenozoic North American ungulates and carnivores reflect van der Hammen's cycles |journal=Die Naturwissenschaften |doi=10.1007/s00114-002-0392-1 |bibcode=2003NW.....90..131M|pmid=12649755 |volume=90 |issue=3 |pages=131–135 |s2cid=21117744 |url=https://www.researchgate.net/publication/10844456 }}</ref> Within the family [[Felidae]] (true cats), members of the [[subfamily]] [[Machairodontinae]] are referred to as saber-toothed cats, and this group is itself divided into three [[Tribe (biology)|tribes]]: [[Metailurini]] (false saber-tooths); [[Homotherini]] ([[scimitar]]-toothed cats); and [[Smilodontini]] ([[dirk]]-toothed cats), to which ''Smilodon'' belongs.{{Sfn|Antón|2013|pp=108–154}}
Members of Smilodontini are defined by their long slender canines with fine to no [[serration]]s, whereas Homotherini are typified by shorter, broad, and more flattened canines, with coarser serrations.{{Sfn|Antón|2013|pp=65–76}} Members of Metailurini were less specialized and had shorter, less flattened canines, and are not recognized as members of Machairodontinae by some researchers.{{Sfn|Antón|2013|pp=108–154}}
Despite the colloquial name "saber-toothed tiger", ''Smilodon'' is not closely related to the modern [[tiger]] (which belongs in the subfamily [[Pantherinae]]), or any other extant felid.<ref name="Berkeley">{{cite web |date=December 2005 |title=What Is a Sabertooth? |url=http://www.ucmp.berkeley.edu/mammal/carnivora/sabretooth.html |access-date=2012-06-12 |publisher=University of California Museum of Paleontology}}</ref> A 1992 ancient DNA analysis suggested that ''Smilodon'' should be grouped with modern cats (subfamilies [[Felinae]] and Pantherinae).<ref>{{cite journal |last1=Janczewski |first1=D. N. |last2=Yuhki |first2=N. |last3=Gilbert |first3=D. A. |last4=Jefferson |first4=G. T. |last5=O'Brien |first5=S. J. |year=1992 |title=Molecular phylogenetic inference from saber-toothed cat fossils of Rancho La Brea |journal=Proceedings of the National Academy of Sciences |volume=89 |issue=20 |pages=9769–9773 |bibcode=1992PNAS...89.9769J |doi=10.1073/pnas.89.20.9769 |pmc=50214 |pmid=1409696 |doi-access=free}}</ref> A 2005 study found that ''Smilodon'' belonged to a separate lineage.<ref name="Barnett">{{cite journal |last1=Barnett |first1=R. |last2=Barnes |first2=I. |last3=Phillips |first3=M. J. |last4=Martin |first4=L. D. |last5=Harington |first5=C. R. |last6=Leonard |first6=J. A. |last7=Cooper |first7=A. |year=2005 |title=Evolution of the extinct sabretooths and the American cheetah-like cat |journal=Current Biology |volume=15 |issue=15 |pages=R589–R590 |bibcode=2005CBio...15.R589B |doi=10.1016/j.cub.2005.07.052 |pmid=16085477 |s2cid=17665121 |doi-access=free}}</ref> A study published in 2006 confirmed this, showing that the Machairodontinae [[Speciation|diverged]] early from the ancestors of living cats and were not closely related to any living species.<ref>{{cite journal |last1=van den Hoek Ostende |first1=L. W. |last2=Morlo |first2=M. |last3=Nagel |first3=D. |year=2006 |title=Majestic killers: the sabre-toothed cats (Fossils explained 52) |journal=Geology Today |volume=22 |issue=4 |pages=150–157 |doi=10.1111/j.1365-2451.2006.00572.x |s2cid=128960196}}</ref> The ancestors of living cats and Machairodontinae estimated to have diverged around 20 million years ago.<ref name="Paijmans2017" /> The following [[cladogram]] based on fossils and DNA analysis shows the placement of ''Smilodon'' among extinct and extant felids, after Rincón and colleagues, 2011:<ref name="Rincón2011">{{cite journal |last1=Rincón |first1=A. |last2=Prevosti |first2=F. |last3=Parra |first3=G. |year=2011 |title=New saber-toothed cat records (Felidae: Machairodontinae) for the Pleistocene of Venezuela, and the Great American Biotic Interchange |journal=Journal of Vertebrate Paleontology |volume=31 |issue=2 |pages=468–478 |bibcode=2011JVPal..31..468R |doi=10.1080/02724634.2011.550366 |jstor=25835839 |s2cid=129693331 |hdl-access=free |hdl=11336/69016}}</ref>
{{clade| style=font-size:85%; line-height:85%
|label1=[[Felidae]]
|1={{clade
|1=''[[Proailurus]]''
|2={{clade
|1=''[[Pseudaelurus]]''
|2={{clade
|1={{clade
|label1=[[Pantherinae]]
|1=''[[Panthera]]'' (tigers, lions, jaguars, and leopards)[[File:Lydekker - Leopard (white background).JPG|70 px]]
|label2=[[Felinae]]
|2={{clade
|1=''[[Caracal (genus)|Caracal]]''[[File:Felis caracal - 1818-1842 - Print - Iconographia Zoologica - Special Collections University of Amsterdam -(White Background).jpg|50 px]]
|2={{clade
|1=''[[Leopardus]]'' ([[ocelot]] and relatives)[[File:Felis pardalis - 1834 - Print - Iconographia Zoologica - Special Collections University of Amsterdam -(White Background).jpg|50px]]
|2={{clade
|1=''[[Felis]]'' ([[domestic cats]] and relatives)[[File:Felis chaus - 1700-1880 - Print - Iconographia Zoologica - Special Collections University of Amsterdam -(White Background).jpg|50px]]
|2={{clade
|1=''[[Herpailurus]]'' (jaguarundi) [[File:Lydekker - Eyra White background.jpg|45 px]]
|2={{clade
|1=''[[Miracinonyx]]'' [[File:Miracinonyx inexpectatus.jpg|55 px]]
|2=''[[Puma (genus)|Puma]]'' (cougar)[[File:Felis concolor - 1818-1842 - Print - Iconographia Zoologica - Special Collections University of Amsterdam -(white background).jpg|65 px]]}} }} }} }} }} }}
|label2=[[Machairodontinae]]
|2={{clade
|1=''[[Dinofelis]]'' [[File:Dinofelis15DB.jpg|70 px]]
|2={{clade
|1={{clade
|1=''[[Nimravides]]''
|2={{clade
|1=''[[Machairodus]]'' [[File:Machairodus from Cerro de Batallones.png|50 px]]
|2={{clade
|1=''[[Homotherium]]'' [[File:H. serum.png|60 px]]
|2=''[[Xenosmilus]]''<span style="{{MirrorH}}">[[File:Xenosmilus with concealed canine.jpg|60 px]]</span> }} }} }}
|2={{clade
|1=''[[Paramachairodus]]''
|2={{clade
|1=''[[Megantereon]]''
|label2='''''Smilodon'''''
|2={{clade
|1='''''Smilodon gracilis'''''<span style="{{MirrorH}}">[[File:Saber Toothed Tiger (PSF).png|55 px]]</span>
|2={{clade
|1='''''Smilodon populator'''''[[File:Smilodon pop2 15.jpg|67 px]]
|2='''''Smilodon fatalis'''''[[File:Smilodon fatalis Knight (white background).jpg|67 px]] }} }} }} }} }} }} }} }} }} }}
The earliest felids are known from the [[Oligocene]] of Europe, such as ''[[Proailurus]]'', and the earliest one with saber-tooth features is the [[Miocene]] genus ''[[Pseudaelurus]]''.{{Sfn|Antón|2013|pp=108–154}} The skull and mandible morphology of the earliest saber-toothed cats was similar to that of the modern [[Neofelis|clouded leopards]] (''Neofelis''). The lineage further adapted to the precision killing of large animals by developing elongated canine teeth and wider gapes, in the process sacrificing high [[Bite force quotient|bite force]].<ref>{{cite journal |last=Christiansen |first=P. |year=2008 |title=Evolution of skull and mandible shape in cats (Carnivora: Felidae) |journal=PLOS ONE |doi=10.1371/journal.pone.0002807 |pmid=18665225 |pmc=2475670 |bibcode=2008PLoSO...3.2807C |volume=3 |issue=7 |page=e2807|doi-access=free }} {{open access}}</ref> As their canines became longer, the bodies of the cats became more robust for immobilizing prey.{{Sfn|Antón|2013|pp=65–76}} In [[Autapomorphy|derived]] smilodontins and homotherins, the [[lumbar]] region of the spine and the tail became shortened, as did the hind limbs.{{Sfn|Antón|2013|pp=108–154}} Machairodonts once represented a dominant group of felids distributed across Africa, Eurasia and the North America during the Miocene and Pliocene epochs,<ref>{{Cite journal |last=Christiansen |first=Per |date=October 2010 |title=Phylogeny of the sabertoothed felids ( Carnivora: Felidae: Machairodontinae) |url=https://onlinelibrary.wiley.com/doi/10.1111/cla.12008 |journal=Cladistics |language=en |volume=29 |issue=5 |pages=543–559 |doi=10.1111/cla.12008 |pmid=34814379 |issn=0748-3007}}</ref> but progressively declined over the course of the Pleistocene,<ref>{{Cite journal |last1=Piras |first1=Paolo |last2=Silvestro |first2=Daniele |last3=Carotenuto |first3=Francesco |last4=Castiglione |first4=Silvia |last5=Kotsakis |first5=Anastassios |last6=Maiorino |first6=Leonardo |last7=Melchionna |first7=Marina |last8=Mondanaro |first8=Alessandro |last9=Sansalone |first9=Gabriele |last10=Serio |first10=Carmela |last11=Vero |first11=Veronica Anna |last12=Raia |first12=Pasquale |date=May 2018 |title=Evolution of the sabertooth mandible: A deadly ecomorphological specialization |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018217310465 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=496 |pages=166–174 |doi=10.1016/j.palaeo.2018.01.034|bibcode=2018PPP...496..166P |hdl=2158/1268434 |hdl-access=free }}</ref> by the [[Late Pleistocene]], only two genera of machairodonts remained, ''Smilodon'', and the distantly related ''[[Homotherium]]'', both largely confined to the Americas. Based on [[mitochondrial DNA]] sequences [[Ancient DNA|extracted from ancient bones]], the lineages of ''Homotherium'' and ''Smilodon'' are estimated to have diverged about 18 million years ago.<ref name="Paijmans2017">{{cite journal|last1= Paijmans|first1=J. L. A.|last2= Barnett|first2= R.|last3= Gilbert|first3=M. T. P.|last4= Zepeda-Mendoza|first4=M. L.|last5= Reumer|first5=J. W. F.|last6=de Vos|first6= J.|last7= Zazula|first7= G.|last8= Nagel|first8= D.|last9= Baryshnikov|first9=G. F.|last10= Leonard|first10=J. A.|last11= Rohland|first11= N.|last12 =Westbury|first12=M. V.|last13= Barlow|first13= A.|last14= Hofreiter|first14= M.|title= Evolutionary History of Saber-Toothed Cats Based on Ancient Mitogenomics|journal= Current Biology|volume=27|issue=21|pages=3330–3336.e5|date= 2017-10-19|doi= 10.1016/j.cub.2017.09.033|pmid=29056454|doi-access= free|bibcode=2017CBio...27E3330P }}</ref>
The earliest species of ''Smilodon'' is ''S.&nbsp;gracilis'', which existed from 2.5 [[Mya (unit)|million]] to 500,000 years ago (early [[Blancan]] to [[Irvingtonian]] ages) and was the successor in North America of ''Megantereon'', from which it probably evolved. ''Megantereon'' itself had entered North America from [[Eurasia]] during the [[Pliocene]], along with ''Homotherium''. ''S.&nbsp;gracilis'' reached the northern regions of South America in the [[Early Pleistocene]] as part of the [[Great American Interchange]].<ref name="Rincón2011" />{{Sfn|Antón|2013|pp=65–76}} ''S.&nbsp;fatalis'' existed 1.6 million–10,000 years ago (late Irvingtonian to [[Rancholabrean]] ages), and replaced ''S.&nbsp;gracilis'' in North America.<ref name=Kurten /> ''S.&nbsp;populator'' existed 1 million–10,000 years ago ([[Ensenadan]] to [[Lujanian]] ages); it occurred in the eastern parts of South America.<ref>{{cite journal |last1=de Castro |first1=Mariela Cordeiro |last2=Langer |first2=Max Cardoso |year=2008 |title=New postcranial remains of ''Smilodon populator'' Lund, 1842 from South-Central Brazil |journal=Revista Brasileira de Paleontologia |doi=10.4072/rbp.2008.3.06 |volume=11 |issue=3 |pages=199–206 |doi-access=free }}</ref>
== Description ==
[[File:Wiki Smilodon Size.svg|thumb|right|Size of the three ''Smilodon'' species compared to a human]]
=== Skeleton ===
''Smilodon'' was around the size of modern [[big cat]]s, but was more robustly built. It had a reduced [[lumbar region]], high [[scapula]], short tail, and broad limbs with relatively short feet.<ref name="Turner" /><ref name="Berkeley"/> ''Smilodon'' is most famous for its relatively long canine teeth, which are the longest found in the saber-toothed cats, at about {{cvt|28|cm}} long in the largest species, ''S. populator''.<ref name="Turner">{{cite book |last1=Turner |first1=A. |last2=Antón |first2=M. |year=1997 |title=The Big Cats and Their Fossil Relatives: An Illustrated Guide to Their Evolution and Natural History |publisher=Columbia University Press |isbn=978-0-231-10229-2 |oclc=34283113 |pages=57–58, 67–68 |url=http://google.com/books?id=lUB9I01-v04C&printsec=frontcover}}</ref> The canines were slender and had fine serrations on the front and back side.<ref name="Slater">{{cite journal |last1=Slater |first1=G. J. |last2=Valkenburgh |first2=B. V. |year=2008 |title=Long in the tooth: evolution of sabertooth cat cranial shape |journal=Paleobiology |issn=0094-8373 |doi=10.1666/07061.1 |volume=34 |issue=3 |pages=403–419|bibcode=2008Pbio...34..403S |s2cid=85353590 }}</ref> The skull was robustly proportioned and the [[snout|muzzle]] was short and broad. The [[Zygomatic bone#In other animals|cheek bones]] (zygomata) were deep and widely arched, the [[sagittal crest]] was prominent, and the [[frontal region]] was slightly convex. The mandible had a flange on each side of the front. The upper incisors were large, sharp, and slanted forwards. There was a [[diastema]] (gap) between the incisors and molars of the mandible. The lower incisors were broad, recurved, and placed in a straight line across. The p3 [[premolar]] tooth of the mandible was present in most early specimens, but lost in later specimens; it was only present in 6% of the La Brea sample.<ref name="Status" /> There is some dispute over whether ''Smilodon'' was [[sexually dimorphic]]. Some studies of ''S. fatalis'' fossils have found little difference between the sexes.<ref name="Van Valenburgh">{{cite journal |last1=Van Valkenburgh |first1=B. |last2=Sacco |first2=T. |year=2002 |title=Sexual dimorphism, social behavior and intrasexual competition in large Pleistocene carnivorans |journal=Journal of Vertebrate Paleontology |jstor=4524203 |doi=10.1671/0272-4634(2002)022[0164:sdsbai]2.0.co;2 |volume=22 |issue=1 |pages=164–169|s2cid=86156959 }}</ref><ref name="Meachen-Samuels">{{cite journal |last1=Meachen-Samuels |first1=J. |last2=Binder |first2=W. |year=2010 |title=Sexual dimorphism and ontogenetic growth in the American lion and sabertoothed cat from Rancho La Brea |journal=Journal of Zoology |doi=10.1111/j.1469-7998.2009.00659.x |volume=280 |issue=3 |pages=271–279 }}</ref> Conversely, a 2012 study found that, while fossils of ''S. fatalis'' show less variation in size among individuals than modern ''Panthera'', they do appear to show the same difference between the sexes in some traits.<ref name="Christiansen">{{cite journal |last1=Christiansen |first1=Per |last2=Harris |first2=John M. |year=2012 |title=Variation in Craniomandibular Morphology and Sexual Dimorphism in Pantherines and the Sabercat Smilodon fatalis |journal=PLOS ONE |bibcode=2012PLoSO...748352C |doi=10.1371/journal.pone.0048352 |pmid=23110232 |pmc=3482211 |volume=7 |issue=10 |pages=e48352|doi-access=free }}</ref>
''S. gracilis'' was the smallest species, estimated at {{cvt|55|to|100|kg}} in weight, about the size of a [[jaguar]]. It was similar to its predecessor ''Megantereon'' of the same size, but its dentition and skull were more advanced, approaching ''S. fatalis''.<ref name="Body size of Smilodon" />{{Sfn|Antón|2013|pp=108–154}} ''S. fatalis'' was intermediate in size between ''S. gracilis'' and ''S. populator''.<ref name="Turner" /> It ranged from {{cvt|160|to|280|kg}}.<ref name="Body size of Smilodon">{{cite journal |last1=Christiansen |first1=Per |last2=Harris |first2=John M. |year=2005 |title=Body size of ''Smilodon'' (Mammalia: Felidae) |journal=Journal of Morphology |doi=10.1002/jmor.10384 |pmid=16235255 |volume=266 |issue=3 |pages=369–84|s2cid=27233870 }}</ref> and reached a shoulder height of {{cvt|100|cm}} and body length of {{cvt|175|cm}}.<ref name="San Diego">{{cite web |date=January 2009 |title=Saber-Toothed Cat, ''Smilodon fatalis'' |publisher=San Diego Zoo Global |url=http://library.sandiegozoo.org/factsheets/_extinct/smilodon/smilodon.htm#physical |access-date=2013-05-07 |archive-url=https://web.archive.org/web/20130203065411/http://library.sandiegozoo.org/factsheets/_extinct/smilodon/smilodon.htm#physical |archive-date=2013-02-03 |url-status=dead }}</ref> It was similar to a lion in dimensions, but was more robust and muscular, and therefore had a larger body mass. Its skull was also similar to that of ''Megantereon'', though more massive and with larger canines.{{Sfn|Antón|2013|pp=108–154}} ''S. populator'' was among the [[List of largest mammals#Carnivorans (Carnivora)|largest known felids]], with a body mass range from {{cvt|220|kg}} to over {{cvt|400|kg}},<ref name="Body size of Smilodon" /> and one estimate suggesting up to {{cvt|470|kg}}.<ref name="Sorkin">{{cite journal |last=Sorkin |first=B. |year=2008 |title=A biomechanical constraint on body mass in terrestrial mammalian predators |journal=[[Lethaia]] |volume=41 |issue=4 |pages=333–347 |doi=10.1111/j.1502-3931.2007.00091.x|bibcode=2008Letha..41..333S }}</ref> A particularly large ''S. populator'' skull from Uruguay measuring {{cvt|39.2|cm}} in length indicates this individual may have weighed as much as {{cvt|436|kg}}.<ref name="LargeSkull">{{cite journal |last1=Manzuetti |first1=A. |last2=Perea |first2=D. |last3=Jones |first3=W. |last4=Ubilla |first4=M. |last5=Rinderknecht |first5=A. |title=An extremely large saber-tooth cat skull from Uruguay (late Pleistocene–early Holocene, Dolores Formation): body size and paleobiological implications |journal=Alcheringa: An Australasian Journal of Palaeontology |date=2020 |volume=44 |issue=2 |pages=332–339 |doi=10.1080/03115518.2019.1701080|bibcode=2020Alch...44..332M |s2cid=216505747 |url=https://www.academia.edu/73338127}}</ref> It stood at a shoulder height of {{cvt|120|cm}}.<ref name="Turner" /> Compared to ''S.&nbsp;fatalis'', ''S.&nbsp;populator'' was more robust and had a more elongated and narrow skull with a straighter upper profile, higher positioned [[nasal bone]]s, a more vertical [[occiput]], more massive [[metapodial]]s and slightly longer forelimbs relative to hindlimbs.{{Sfn|Antón|2013|pp=108–154}}<ref name=Kurten>{{cite journal |last1=Kurtén |first1=B. |last2=Werdelin |first2=L. |year=1990 |title=Relationships between North and South American ''Smilodon'' |journal=Journal of Vertebrate Paleontology |doi=10.1080/02724634.1990.10011804 |jstor=4523312 |volume=10 |issue=2 |pages=158–169|bibcode=1990JVPal..10..158K }}</ref> Large [[fossil tracks]] from Argentina (for which the [[ichnotaxon]] name ''Smilodonichium'' has been proposed) have been attributed to ''S. populator'', and measure {{cvt|17.6|cm}} by {{cvt|19.2|cm}}.<ref>{{cite news |date=May 26, 2016 |title=Hallazgo inédito en Miramar: huellas fosilizadas de un gran tigre dientes de sable |work=0223.com.ar |publisher=0223 |language=es |url=http://www.0223.com.ar/nota/2016-5-26-hallazgo-inedito-en-miramar-huellas-fosilizadas-de-un-gran-tigre-dientes-de-sable |access-date=28 May 2016}}</ref> This is larger than tracks of the [[Bengal tiger]], to which the footprints have been compared.<ref>{{Cite journal|last=Perkins |first=Sid |date=June 10, 2016 |title=First fossil footprints of saber-toothed cats are bigger than Bengal tiger paws |journal=Science |doi=10.1126/science.aag0602 |url=https://www.science.org/content/article/first-fossil-footprints-saber-toothed-cats-are-bigger-bengal-tiger-paws}}</ref>
===External features===
{{multiple image |align = right |direction = horizontal |total_width = 400
|image1 = Smilodon Knight.jpg
|alt1 =
|image2 = Smilodon fatalis.jpg
|alt2 =
|footer = ''S. populator'' [[paleoart|restored]] with plain [[Coat (animal)|coat]] by [[Charles R. Knight]] in 1903 (left), and ''S. fatalis'' restored with spotted coat (right), both of which are considered possibilities
}}
''Smilodon'' and other saber-toothed cats have been reconstructed with both plain-colored [[Coat (animal)|coats]] and with spotted patterns (which appears to be the ancestral condition for [[feliforms]]), both of which are considered possible.{{Sfn|Antón|2013|pp=157–176}} Studies of modern cat species have found that species that live in the open tend to have uniform coats while those that live in more vegetated habitats have more markings, with some exceptions.<ref>{{cite journal |last1=Allen |first1=W. L. |last2=Cuthill |first2=I. C. |last3=Scott-Samuel |first3=N. E. |last4=Baddeley |first4=R. |year=2010 |title=Why the leopard got its spots: relating pattern development to ecology in felids |journal=Proceedings of the Royal Society B |doi=10.1098/rspb.2010.1734 |pmid=20961899 |pmc=3061134 |volume=278 |issue=1710 |pages=1373–1380}}</ref> Some coat features, such as the manes of male lions or the stripes of the tiger, are too unusual to predict from fossils.{{Sfn|Antón|2013|pp=157–176}}
Traditionally, saber-toothed cats have been [[paleoart|artistically restored]] with external features similar to those of extant felids, by artists such as [[Charles R. Knight]] in collaboration with various paleontologists in the early 20th century.{{Sfn|Antón|2013|pp=157–176}} In 1969, paleontologist G.&nbsp;J. Miller instead proposed that ''Smilodon'' would have looked very different from a typical cat and similar to a [[bulldog]], with a lower lip line (to allow its mouth to open wide without tearing the facial tissues), a more retracted nose and lower-placed ears.<ref>{{cite journal |last=Miller |first=G. J. |year=1969 |title=A new hypothesis to explain the method of food ingestion used by ''Smilodon californicus'' Bovard |journal=Tebiwa |volume=12 |pages=9–19}}</ref> Paleoartist [[Mauricio Antón]] and coauthors disputed this in 1998 and maintained that the facial features of ''Smilodon'' were overall not very different from those of other cats. Antón noted that modern animals like the [[hippopotamus]] are able to open their mouths extremely wide without tearing tissue due to a folded [[orbicularis oris muscle]], and such a muscle arrangement exists in modern large felids.<ref name="Anton">{{cite journal |last1=Antón |first1=M. |last2=García-Perea |first2=R. |last3=Turner |first3=A. |year=1998 |title=Reconstructed facial appearance of the sabretoothed felid ''Smilodon'' |journal=Zoological Journal of the Linnean Society |doi=10.1111/j.1096-3642.1998.tb00582.x |volume=124 |issue=4 |pages=369–386|doi-access= }}</ref> Antón stated that [[extant phylogenetic bracketing]] (where the features of the closest extant relatives of a fossil taxon are used as reference) is the most reliable way of restoring the life-appearance of prehistoric animals, and the cat-like ''Smilodon'' restorations by Knight are therefore still accurate.{{Sfn|Antón|2013|pp=157–176}} A 2022 study by Antón and colleagues concluded that the upper canines of ''Smilodon'' would have been visible when the mouth was closed, while those of ''Homotherium'' would have not, after examining fossils and extant big cats.<ref name="Concealed">{{cite journal |last1=Antón |first1=Mauricio |last2=Siliceo |first2=Gema |last3=Pastor |first3=Juan F. |last4=Salesa |first4=Manuel J. |title=Concealed weapons: A revised reconstruction of the facial anatomy and life appearance of the sabre-toothed cat ''Homotherium latidens'' (Felidae, Machairodontinae) |journal=Quaternary Science Reviews |date=2022 |volume=284 |pages=107471 |doi=10.1016/j.quascirev.2022.107471|bibcode=2022QSRv..28407471A |s2cid=248168629 |doi-access=free |hdl=10261/270770 |hdl-access=free }}</ref>
== Paleobiology ==
=== Diet ===
[[File:Smilodon tooth.jpg|thumb|left|''S. populator'' [[canine tooth]]; the tip points to the right]]
An [[apex predator]], ''Smilodon'' primarily hunted large mammals. [[Isotope]]s preserved in the bones of ''S.&nbsp;fatalis'' in the La Brea Tar Pits reveal that [[ruminant]]s like bison (''[[Bison antiquus]]'', which was much larger than the modern [[American bison]]) and camels (''[[Camelops]]'') were most commonly taken by the cats there.<ref name=palaeoecology>{{cite journal|last1=Coltrain |first1=J. B. |last2=Harris |first2=J. M. |last3=Cerling |first3=T. E. |last4=Ehleringer |first4=J. R. |last5=Dearing |first5=M.-D. |last6=Ward |first6=J. |last7=Allen |first7=J. |year=2004 |title=Rancho La Brea stable isotope biogeochemistry and its implications for the palaeoecology of late Pleistocene, coastal southern California |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=205 |issue=3–4 |pages=199–219 |doi=10.1016/j.palaeo.2003.12.008 |url=http://bioweb.biology.utah.edu/dearing/2011/Publications/Stable_Isotopes/LaBrea_animals.pdf |archive-url=https://web.archive.org/web/20111111024742/http://bioweb.biology.utah.edu/dearing/2011/Publications/Stable_Isotopes/LaBrea_animals.pdf |archive-date=November 11, 2011 |url-status=dead |bibcode=2004PPP...205..199C }}</ref>
''Smilodon fatalis'' may have also occasionally preyed upon ''[[Glyptotherium]]'', based on a skull from a juvenile ''Glyptotherium texanum'' recovered from Pleistocene deposits in Arizona that bear the distinctive elliptical puncture marks best matching those of ''Smilodon'', indicating that the predator successfully bit into the skull through the glyptodont's armored cephalic shield.{{sfn|Antón|2013|pp=203–204}} In addition, isotopes preserved in the [[tooth enamel]] of ''S.&nbsp;gracilis'' specimens from Florida show that this species fed on the [[peccary]] ''[[Platygonus]]'' and the [[llama]]-like ''[[Hemiauchenia]]''.<ref>{{cite journal|last=Feranec|first=R. S.|year=2005|title=Growth rate and duration of growth in the adult canine of ''S. gracilis'' and inferences on diet through stable isotope analysis|url=https://www.floridamuseum.ufl.edu/wp-content/uploads/sites/35/2017/03/bulletin-feraneclowres.pdf|journal=Bulletin of the Florida Museum of Natural History|volume=45|issue=4|pages=369–377|doi=10.58782/flmnh.psyo5090 |via=University of Florida}}</ref> Stable carbon isotope measurements of ''S. gracilis'' remains in Florida varied significantly between different sites and show that the species was flexible in its feeding habits.<ref>{{Cite journal |last1=Feranec |first1=Robert S. |last2=DeSantis |first2=Larisa R. G. |date=Summer 2014 |title=Understanding specifics in generalist diets of carnivorans by analyzing stable carbon isotope values in Pleistocene mammals of Florida |url=https://www.cambridge.org/core/journals/paleobiology/article/abs/understanding-specifics-in-generalist-diets-of-carnivorans-by-analyzing-stable-carbon-isotope-values-in-pleistocene-mammals-of-florida/7BAB33D0127FE87879C677F80F95808C |journal=[[Paleobiology (journal)|Paleobiology]] |language=en |volume=40 |issue=3 |pages=477–493 |doi=10.1666/13055 |bibcode=2014Pbio...40..477F |issn=0094-8373 |access-date=21 January 2024 |via=Cambridge Core}}</ref> Isotopic studies of [[dire wolf]] (''Aenocyon dirus'') and [[American lion]] (''Panthera atrox'') bones show an overlap with ''S.&nbsp;fatalis'' in prey, which suggests that they were competitors.<ref name=palaeoecology /> More detailed isotope analysis however, indicates that ''Smilodon fatalis'' preferred forest-dwelling prey such as tapirs, deer and forest-dwelling bison as opposed to the dire wolves' preferences for prey inhabiting open areas such as grassland.<ref>{{cite journal|first1=Larisa R. G. |last1=DeSantis|first2=Jonathan M. |last2=Crites|first3=Robert S. |last3=Feranec|first4=Kena |last4=Fox-Dobbs|first5=Aisling B. |last5=Farrell|first6=John M. |last6=Harris|first7=Gary T. |last7=Takeuchi|first8=Thure E. |last8=Cerling|year=2019|title=Causes and Consequences of Pleistocene Megafaunal Extinctions as Revealed from Rancho La Brea Mammals|journal=Current Biology|volume=29|issue=15|pages=2488–2495|doi=10.1016/j.cub.2019.06.059 |pmid=31386836|doi-access=free|bibcode=2019CBio...29E2488D }}</ref> The availability of prey in the [[La Brea Tar Pits|Rancho La Brea]] area was likely comparable to modern [[East Africa]].<ref>{{cite journal |last1=Vanvalkenburgh |first1=B. |last2=Hertel |first2=F. |year=1993 |title=Tough Times at La Brea: Tooth Breakage in Large Carnivores of the Late Pleistocene|journal=Science |pmid=17770024 |bibcode=1993Sci...261..456V |doi=10.1126/science.261.5120.456 |volume=261 |issue=5120 |pages=456–459|s2cid=39657617 }}</ref>
[[File:Smilodon stalking Palaeolama.jpg|thumb|right|Two ''S. populator'' stalking a ''[[Palaeolama]]'' group in Brazil]]
As ''Smilodon'' migrated to South America, its diet changed; bison were absent, the [[Equus (genus)|horses]] and [[proboscidea]]ns were different, and native ungulates such as [[toxodonts]] and [[litopterns]] were completely unfamiliar, yet ''S.&nbsp;populator'' thrived as well there as its relatives in North America.{{Sfn|Antón|2013|pp=65–76}} Isotopic analysis for ''S. populator'' suggests that its main prey species included the camel like litoptern ungulate ''[[Macrauchenia]]'',<ref>{{Cite journal |last1=Bocherens |first1=Hervé |last2=Cotte |first2=Martin |last3=Bonini |first3=Ricardo |last4=Scian |first4=Daniel |last5=Straccia |first5=Pablo |last6=Soibelzon |first6=Leopoldo |last7=Prevosti |first7=Francisco J. |date=May 2016 |title=Paleobiology of sabretooth cat Smilodon populator in the Pampean Region (Buenos Aires Province, Argentina) around the Last Glacial Maximum: Insights from carbon and nitrogen stable isotopes in bone collagen |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018216000912 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=449 |pages=463–474 |bibcode=2016PPP...449..463B |doi=10.1016/j.palaeo.2016.02.017 |hdl=11336/43965|hdl-access=free }}</ref> the rhinoceros-like ungulate ''[[Toxodon platensis]]'', the large armadillo relatives ''[[Pachyarmatherium]]'', ''[[Holmesina]]'', species of the [[glyptodont]] genus ''[[Panochthus]]'', the llama ''[[Palaeolama]]'', the ground sloth ''[[Catonyx]]'', and the equine ''[[Equus neogeus]]'', and the crocodilian ''[[Caiman latirostris]]''. This analysis of its diet also indicates that ''S. populator'' hunted both in open and forested habitats.<ref>{{Cite journal|last1=Dantas|first1=Mário André Trindade|last2=Cherkinsky|first2=Alexander|last3=Lessa|first3=Carlos Micael Bonfim|last4=Santos|first4=Luciano Vilaboim|last5=Cozzuol|first5=Mario Alberto|last6=Omena|first6=Érica Cavalcante|last7=Silva|first7=Jorge Luiz Lopes|last8=Sial|first8=Alcides Nóbrega|last9=Bocherens|first9=Hervé|date=2020-07-14|title=Isotopic paleoecology (δ13C, δ18O) of a late Pleistocene vertebrate community from the Brazilian Intertropical Region|journal=Revista Brasileira de Paleontologia|language=en|volume=23|issue=2|pages=138–152|doi=10.4072/rbp.2020.2.05|issn=2236-1715|doi-access=free}}</ref> The differences between the North and South American species may be due to the difference in prey between the two continents.<ref name=Kurten /> ''Smilodon'' may have avoided eating bone and would have left enough food for scavengers.<ref>{{cite journal |last1=Van Valkenburgh |first1=B. |last2=Teaford |first2=M. F. |last3=Walker |first3=A. |year=1990 |title=Molar microwear and diet in large carnivores: inferences concerning diet in the sabretooth cat, ''Smilodon fatalis'' |journal=Journal of Zoology |doi=10.1111/j.1469-7998.1990.tb05680.x |volume=222 |issue=2 |pages=319–340 }}</ref> [[Coprolite]]s assigned to ''S. populator'' recovered from Argentina preserve [[osteoderms]] from the ground sloth ''[[Mylodon]]''  and a ''[[Lama (genus)|Lama]]'' scaphoid bone. In addition to this unambiguous evidence of bone consumption, the coprolites suggest that ''Smilodon'' had a more generalist diet than previously thought.<ref>{{Cite journal |last1=Moreno Rodríguez |first1=Ana P. |last2=Chimento |first2=Nicolás R. |last3=Agnolín |first3=Federico L. |last4=Jofré |first4=Guillermo |last5=Gentil |first5=Adriel |title=A possible ''Smilodon'' (Mammalia, Felidae) Coprolite from the Pleistocene of Argentina |date=2022|url=https://www.researchgate.net/publication/362246133 |journal=PALAIOS |volume=37 |issue=7 |pages=402–410 |doi=10.2110/palo.2021.056 |bibcode=2022Palai..37..402M |s2cid=251078622 |issn=1938-5323}}</ref> Examinations of dental microwear from La Brea further suggests that ''Smilodon'' consumed both flesh and bone.<ref>{{Cite journal |last1=DeSantis |first1=Larisa R.G. |last2=Shaw |first2=Christopher A. |title=Sabertooth Cats with Toothaches: Impacts of Dental Injuries on Feeding Behavior in Late Pleistocene Smilodon Fatalis (Mammalia, Felidae) from Rancho la Brea (Los Angeles, California) |journal=Geological Society of America Abstracts with Programs |date=2018 |url=https://gsa.confex.com/gsa/2018AM/webprogram/Paper322567.html |page=322567 |doi=10.1130/abs/2018AM-322567|volume=50|issue=6}}</ref> ''Smilodon'' itself may have scavenged dire wolf kills.<ref>{{cite journal |last=Van Valkenburgh |first=B. |year=1991 |title=Iterative evolution of hypercarnivory in canids (Mammalia: Carnivora): evolutionary interactions among sympatric predators |journal=Paleobiology |jstor=2400749 |volume=17 |issue=4 |pages=340–362|doi=10.1017/S0094837300010691 |bibcode=1991Pbio...17..340V |s2cid=251052044 }}</ref> It has been suggested that ''Smilodon'' was a pure scavenger that used its canines for display to assert dominance over carcasses, but this theory is not supported today as no modern terrestrial mammals are pure scavengers.{{Sfn|Antón|2013|pp=176–216}}
=== Predatory behavior ===
[[File:Felipeda miramarensis huellas de smilodon.jpg|thumb|right|Tracks from Argentina which may have been produced by ''Smilodon'']]
The [[brain]] of ''Smilodon'' had [[Sulcus (neuroanatomy)|sulcal]] patterns similar to modern cats, which suggests an increased complexity of the regions that control the sense of hearing, sight, and coordination of the limbs. Felid saber-tooths in general had relatively small [[Cat senses#Sight|eyes]] that were not as forward-facing as those of modern cats, which have good [[binocular vision]] to help them move in trees.{{Sfn|Antón|2013|pp=176–216}} ''Smilodon'' was likely an [[ambush predator]] that concealed itself in dense vegetation, as its limb proportions were similar to modern forest-dwelling cats,<ref>{{cite journal |last=Gonyea |first=W. J. |year=1976 |title=Behavioral implications of saber-toothed felid morphology |journal=Paleobiology |jstor=2400172 |volume=2 |issue=4 |pages=332–342|doi=10.1017/S0094837300004966 |bibcode=1976Pbio....2..332G |s2cid=87481727 }}</ref> and its short tail would not have helped it balance while running.<ref name="Berkeley"/> Unlike its ancestor ''Megantereon'', which was at least partially [[scansorial]] and therefore able to climb trees, ''Smilodon'' was probably completely terrestrial due to its greater weight and lack of climbing adaptations.<ref name="Anton 2013">{{cite book |last=Anton |first=Mauricio |author-link=Mauricio Anton |date=2013 |title=Sabertooth}}</ref> Tracks from Argentina named ''Felipeda miramarensis'' in 2019 may have been produced by ''Smilodon''. If correctly identified, the tracks indicate that the animal had fully retractible claws, [[plantigrade]] feet, lacked strong [[supination]] capabilities in its paws, notably robust forelimbs compared to the hindlimbs, and was probably an ambush predator.<ref name="Tracks">{{cite journal |last1=Agnolin |first1=F. L. |last2=Chimento |first2=N. R. |last3=Campo |first3=D. H. |last4=Magnussen |first4=M. |last5=Boh |first5=D. |last6=De Cianni |first6=F. |title=Large Carnivore Footprints from the Late Pleistocene of Argentina |journal=Ichnos |date=2019 |volume=26 |issue=2 |pages=119–126 |doi=10.1080/10420940.2018.1479962|bibcode=2019Ichno..26..119A |s2cid=134190731 }}</ref>
The [[heel bone]] of ''Smilodon'' was fairly long, which suggests it was a good jumper.<ref name="Turner" /> Its well-developed flexor and extensor muscles in its [[forearm]]s probably enabled it to pull down, and securely hold down, large prey. Analysis of the cross-sections of ''S.&nbsp;fatalis'' [[humerus|humeri]] indicated that they were strengthened by [[cortical thickening]] to such an extent that they would have been able to sustain greater loading than those of extant big cats, or of the extinct American lion. The humerus cortical wall in ''S. fatalis'' was a 15 % thicker than excpected in modern big cats of similar size. The thickening of ''S.&nbsp;fatalis'' [[femur]]s was within the range of extant felids.<ref name=forelimbs>{{cite journal |last1=Meachen-Samuels |first1=J. A. |last2=Van Valkenburgh |first2=B. |year=2010 |title=Radiographs reveal exceptional forelimb strength in the sabertooth cat, ''Smilodon fatalis'' |journal=PLOS ONE |issn=1932-6203 |doi=10.1371/journal.pone.0011412 |pmid=20625398 |pmc=2896400 |volume=5 |issue=7 |pages=e11412|bibcode=2010PLoSO...511412M |doi-access=free }} {{open access}}</ref><ref>{{Cite journal |last=Krishnaswamy |first=Dolly J. |date=2 July 2010 |title=ScienceShot: Saber-tooth Tigers Add Powerful Arms to Their Arsenal |url=https://www.science.org/content/article/scienceshot-saber-tooth-tigers-add-powerful-arms-their-arsenal |journal=Science}}</ref>  Its canines were fragile and could not have bitten into bone; due to the risk of breaking, these cats had to subdue and restrain their prey with their powerful forelimbs before they could use their canine teeth, and likely used quick slashing or stabbing bites rather than the slow, suffocating bites typically used by modern cats.<ref name=forelimbs /> On rare occasions, as evidenced by fossils, ''Smilodon'' was willing to risk biting into bone with its canines. This may have been focused more towards competition such as other ''Smilodon'' or potential threats such as other carnivores than on prey.<ref name="Anton 2013" />
[[File:Smilodon bite.png|thumb|left|Maximum gape of a [[saber-toothed cat]] (A) and reconstructions of neck bite in prey of different sizes (B, C)]]
Debate continues as to how ''Smilodon'' killed its prey. Traditionally, the most popular theory is that the cat delivered a deep stabbing bite or open-jawed stabbing thrust to the throat, killing the prey very quickly.<ref name=forelimbs /><ref>{{cite journal |last1=McHenry |first1=C. R. |last2=Wroe |first2=S. |last3=Clausen |first3=P. D. |last4=Moreno |first4=K. |last5=Cunningham |first5=E. |year=2007 |title=Supermodeled sabercat, predatory behavior in ''Smilodon fatalis'' revealed by high-resolution 3D computer simulation |journal=PNAS |doi=10.1073/pnas.0706086104 |pmid=17911253 |pmc=2042153 |bibcode=2007PNAS..10416010M |volume=104 |issue=41 |pages=16010–16015 |doi-access=free }}</ref> Another hypothesis suggests that ''Smilodon'' targeted the belly of its prey. This is disputed, as the curvature of their prey's belly would likely have prevented the cat from getting a good bite or stab.<ref>{{cite journal |last=Anyonge |first=W. |year=1996 |title=Microwear on canines and killing behavior in large carnivores: saber function in ''Smilodon fatalis'' |journal=Journal of Mammalogy |doi=10.2307/1382786 |jstor=1382786 |volume=77 |issue=4 |pages=1059–1067 |doi-access=free }}</ref> In regard to how ''Smilodon'' delivered its bite, the "canine shear-bite" hypothesis has been favored, where flexion of the neck and rotation of the skull assisted in biting the prey, but this may be mechanically impossible. However, evidence from comparisons with ''Homotherium'' suggest that ''Smilodon'' was fully capable of and utilized the canine shear-bite as its primary means of killing prey, based on the fact that it had a thick skull and relatively little trabecular bone, while ''Homotherium'' had both more trabecular bone and a more lion-like clamping bite as its primary means of attacking prey. The discovery, made by Figueirido and Lautenschlager ''et al.,'' published in 2018 suggests extremely different ecological adaptations in both machairodonts.<ref>{{cite journal|last1=Figueirido|first1=B.|last2=Lautenschlager|first2=S.|last3=Pérez-Ramos|first3=A.|last4=Van Valkenburgh|first4=B.|year=2018|title=Distinct Predatory Behaviors in Scimitar- and Dirk-Toothed Sabertooth Cats|journal=Current Biology|volume=28|issue=20|pages=3260–3266.e3|doi=10.1016/j.cub.2018.08.012|pmid=30293717|doi-access=free|bibcode=2018CBio...28E3260F |hdl=10630/29727|hdl-access=free}}</ref> The mandibular flanges may have helped resist bending forces when the mandible was pulled against the hide of a prey animal.<ref name="Brown2014">{{cite journal |last1=Brown |first1=J. G. |year=2014 |title=Jaw function in ''Smilodon fatalis'': a reevaluation of the canine shear-bite and a proposal for a new forelimb-powered class 1 lever model |journal=PLOS ONE |issn=1932-6203 |doi=10.1371/journal.pone.0107456 |pmid=25272032 |pmc=4182664 |volume=9 |issue=10 |pages=e107456|bibcode=2014PLoSO...9j7456B |doi-access=free }} {{open access}}</ref> It has been experimentally proven by means of a machine that recreates the teeth, and simulates the movements of jaws and neck of ''Smilodon fatalis'' (The "Robocat") on bison and elk carcasses, that the stabbing bite to the throat is a much more plausible and practical killing technique than the stabbing bite to the belly.<ref>{{Cite book |last=Wheeler |first=H. Todd |title=The Other Saber-tooths: Scimitar-tooth Cats of the Western Hemisphere |publisher=Johns Hopkins University Press |year=2011 |editor-last=L. Naples |editor-first=Virginia |pages=19–35 |chapter=Experimental Paleontolgy of the Scimitar-tooth and Dirk-tooth Killing Bites |editor-last2=D. Martin |editor-first2=Larry |editor-last3=P. Babiarz |editor-first3=John |chapter-url=https://www.academia.edu/6463625}}</ref>
{{multiple image |align = right |total_width = 350
|image1 = BC-018T-Sabercat-Tarpit-r2-Lo.jpg |alt1 =
|image2 = Smilodon gaping.jpg |alt2 =
|footer = ''S. fatalis'' skull cast (left) and restoration by [[Mauricio Antón]] showing a wide gape
}}
The protruding incisors were arranged in an arch, and were used to hold the prey still and stabilize it while the canine bite was delivered. The contact surface between the canine crown and the gum was enlarged, which helped stabilize the tooth and helped the cat sense when the tooth had penetrated to its maximum extent. Since saber-toothed cats generally had a relatively large [[infraorbital foramen]] (opening) in the skull, which housed nerves associated with the whiskers, it has been suggested the improved senses would have helped the cats' precision when biting outside their field of vision, and thereby prevent breakage of the canines. The blade-like [[carnassial]] teeth were used to cut skin to access the meat, and the reduced molars suggest that they were less adapted for crushing bones than modern cats.{{Sfn|Antón|2013|pp=176–216}} As the food of modern cats enters the mouth through the side while cutting with the carnassials, not the front incisors between the canines, the animals do not need to gape widely, so the canines of ''Smilodon'' would likewise not have been a hindrance when feeding.<ref name="Anton" /> A study published in 2022 of how machairodonts fed revealed that wear patterns on the teeth of ''S. fatalis'' also suggest that it was capable of eating bone to a similar extent as lions. This and comparisons with bite marks left by the contemporary machairodont ''[[Xenosmilus]]'' suggest that ''Smilodon'' and its relatives could efficiently de-flesh a carcass of meat when feeding without being hindered by their long canines.<ref name="carcassconsumption">{{cite journal |last1=Domínguez-Rodrigo |first1=Manuel |last2=Egeland |first2=Charles P. |last3=Cobo-Sánchez |first3=Lucía |last4=Baquedano |first4=Enrique |last5=Hulbert |first5=Richard C. |title=Sabertooth carcass consumption behavior and the dynamics of Pleistocene large carnivoran guilds |journal=Scientific Reports |date=2022 |volume=12 |issue=1 |pages=6045 |doi=10.1038/s41598-022-09480-7| pmid=35501323|pmc=9061710 |bibcode=2022NatSR..12.6045D }}</ref>
Despite being more powerfully built than other large cats, ''Smilodon'' had a weaker bite. Modern big cats have more pronounced [[zygomatic arch]]es, while these were smaller in ''Smilodon'', which restricted the thickness and therefore power of the [[temporalis muscle]]s and thus reduced ''Smilodon''{{'}}s bite force. Analysis of its narrow jaws indicates that it could produce a bite only a third as strong as that of a lion (the bite force quotient measured for the lion is 112).<ref name="NewscientistOct2007">{{cite journal |last=Hecht |first=J. |date=1 October 2007 |title=Sabre-tooth cat had a surprisingly delicate bite |journal=New Scientist |url=https://www.newscientist.com/article/dn12712-sabretooth-cat-had-a-surprisingly-delicate-bite.html}}</ref><ref name="Wroe et al., 2004">{{cite journal |url=http://intern.forskning.no/dokumenter/wroe.pdf |author=Wroe, S. |author2=McHenry2, C. |author3=Thomason, J. |year=2004 |title=Bite club: comparative bite force in big biting mammals and the prediction of predatory behaviour in fossil taxa |journal=Proceedings of the Royal Society |volume=272 |issue=1563 |pages=619–25 |doi=10.1098/rspb.2004.2986 |pmid=15817436 |pmc=1564077 |url-status=dead |archive-url=https://web.archive.org/web/20130825231325/http://intern.forskning.no/dokumenter/wroe.pdf |archive-date=2013-08-25 }}</ref> There seems to be a general rule that the saber-toothed cats with the largest canines had proportionally weaker bites. Analyses of canine [[Flexural strength|bending strength]] (the ability of the canine teeth to resist bending forces without breaking) and bite forces indicate that the saber-toothed cats' teeth were stronger relative to the bite force than those of modern big cats.<ref>{{cite journal |last=Christiansen |first=P. |year=2007 |title=Comparative bite forces and canine bending strength in feline and sabretooth felids: implications for predatory ecology |journal=Zoological Journal of the Linnean Society |doi=10.1111/j.1096-3642.2007.00321.x |volume=151 |issue=2 |pages=423–437 |doi-access=free }}</ref> In addition, ''Smilodon''{{'s}} gape could have reached over 110 degrees,<ref>{{cite journal |last1=Andersson |first1=K. |last2=Norman |first2=D. |last3=Werdelin |first3=L. |year=2011 |title=Sabretoothed carnivores and the killing of large prey |journal=PLOS ONE |doi=10.1371/journal.pone.0024971 |bibcode=2011PLoSO...624971A |pmid=22039403 |pmc=3198467 |volume=6 |issue=10 |page=e24971|doi-access=free }} {{open access}}</ref> while that of the modern lion reaches 65 degrees.<ref>{{cite journal |last=Martin |first=L. D. |year=1980 |title=Functional morphology and the evolution of cats |journal=Transactions of the Nebraska Academy of Sciences |volume=8 |pages=141–154 |url=http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1286&context=tnas&sei-redir=1}}</ref> This made the gape wide enough to allow ''Smilodon'' to grasp large prey despite the long canines.<ref name="Anton" /> A 2018 study compared the killing behavior of ''Smilodon fatalis'' and ''Homotherium serum'', and found that the former had a strong skull with little [[trabecular bone]] for a stabbing canine-shear bite, whereas the latter had more trabecular bone and used a clamp and hold style more similar to lions. The two would therefore have held distinct ecological niches.<ref name="DistinctPredatoryBehaviors">{{cite journal |last1=Figueirido |first1=B. |last2=Lautenschlager |first2=S. |last3=Pérez-Ramos |first3=A. |last4=Van Valkenburgh |first4=B. |title=Distinct Predatory Behaviors in Scimitar- and Dirk-Toothed Sabertooth Cats |journal=Current Biology |date=2018 |volume=28 |issue=20 |pages=3260–3266.e3 |doi=10.1016/j.cub.2018.08.012|pmid=30293717 |url=https://research.birmingham.ac.uk/portal/en/publications/distinct-predatory-behaviors-in-scimitar-and-dirktoothed-sabertooth-cats(2f520864-4cce-4550-acf5-47c699b69100).html |doi-access=free |bibcode=2018CBio...28E3260F |hdl=10630/29727 |hdl-access=free }}</ref>
By finding of correlation between relative [[cribriform plate]] size and repertoire of functional [[olfactory receptor]] genes, it was found that ''S. fatalis'' had a slightly smaller repertoire than modern felids with 600 olfatory receptor genes, compared to 677 of a [[Cat|domestic cat]]. This indicates that ''S. fatalis'' used less olfaction for its daily activities than modern felids.<ref>{{Cite journal |last1=Bird |first1=Deborah J. |last2=Murphy |first2=William J. |last3=Fox-Rosales |first3=Lester |last4=Hamid |first4=Iman |last5=Eagle |first5=Robert A. |last6=Van Valkenburgh |first6=Blaire |date=2018 |title=Olfaction written in bone: cribriform plate size parallels olfactory receptor gene repertoires in Mammalia |journal=Proceedings of the Royal Society B: Biological Sciences |language=en |volume=285 |issue=1874 |pages=20180100 |doi=10.1098/rspb.2018.0100 |issn=0962-8452 |pmc=5879636 |pmid=29540522}}</ref>
=== Natural traps ===
[[File:Smilodon and Canis dirus.jpg|thumb|''S. fatalis'' fighting [[dire wolves]] over a [[Columbian mammoth]] carcass in the [[La Brea Tar Pits]], by [[Robert Bruce Horsfall]], 1913]]
Many ''Smilodon'' specimens have been excavated from [[asphalt seeps]] that acted as natural carnivore traps. Animals were accidentally trapped in the seeps and became bait for predators that came to scavenge, but these were then trapped themselves. The best-known of such traps are at La Brea in Los Angeles, which have produced over 166,000 ''Smilodon fatalis'' specimens<ref>{{cite journal|last1=Shaw|first1=Christopher A.|last2=Quinn|first2=James P.|title=The Addition of ''Smilodon fatalis'' (Mammalia: Carnivora: Felidae) to the Biota of the Late Pleistocene Carpinteria Asphalt Deposits in California, with Ontogenetic and Ecologic Implications for the Species|publisher=Natural History Museum of Los Angeles County|journal=Science Series 42: Contributions in Science |issue=A special volume entitled La Brea and Beyond: the Paleontology of Asphalt–Preserved Biotas in commemoration of the 100th anniversary of the Natural History Museum of Los Angeles County's excavations at Rancho La Brea|editor=John M. Harris|date=September 15, 2015|pages=91–95|url=https://tarpits.org/sites/default/files/blog_images/La%20Brea%20and%20Beyond%202015.%20NHM%20Science%20Science%20No.%2042.pdf|access-date=September 30, 2017|archive-url=https://web.archive.org/web/20161225011549/http://www.tarpits.org/sites/default/files/blog_images/La%20Brea%20and%20Beyond%202015.%20NHM%20Science%20Science%20No.%2042.pdf|archive-date=December 25, 2016|url-status=dead}}</ref> that form the largest collection in the world. The sediments of the pits there were accumulated 40,000 to 10,000 years ago, in the [[Late Pleistocene]]. Though the trapped animals were buried quickly, predators often managed to remove limb bones from them, but they were themselves often trapped and then scavenged by other predators; 90% of the excavated bones belonged to predators.{{Sfn|Antón|2013|pp=30–33}}
The Talara Tar Seeps in Peru represent a similar scenario, and have also produced fossils of ''Smilodon''. Unlike in La Brea, many of the bones were broken or show signs of weathering. This may have been because the layers were shallower, so the thrashing of trapped animals damaged the bones of previously trapped animals. Many of the carnivores at Talara were juveniles, possibly indicating that inexperienced and less fit animals had a greater chance of being trapped. Though Lund thought accumulations of ''Smilodon'' and herbivore fossils in the Lagoa Santa Caves were due to the cats using the caves as dens, these are probably the result of animals dying on the surface, and water currents subsequently dragging their bones to the floor of the cave, but some individuals may also have died after becoming lost in the caves.{{Sfn|Antón|2013|pp=30–33}}
=== Social life ===
[[File:La Brea Tar Pits.jpg|thumb|left|''S. fatalis'' pair approaching a group of the [[Ground sloth|ground sloth]] ''[[Paramylodon]]'', one mired, at the La Brea Tar Pits, by Knight, 1921]]
Scientists debate whether ''Smilodon'' was [[social animal|social]]. One study of African predators found that social predators like [[lion]]s and [[spotted hyena]]s respond more to the [[distress call]]s of prey than solitary species. Since ''S.&nbsp;fatalis'' fossils are common at the La Brea Tar Pits, and were likely attracted by the distress calls of stuck prey, this could mean that this species was social as well.<ref>{{cite journal |last1=Carbone |first1=C. |last2=Maddox |first2=T. |last3=Funston |first3=P. J. |last4=Mills |first4=M. G. L. |last5=Grether |first5=G. F. |last6=Van Valkenburgh |first6=B. |year=2009 |title=Parallels between playbacks and Pleistocene tar seeps suggest sociality in an extinct sabretooth cat, ''Smilodon'' |journal=Biology Letters |doi=10.1098/rsbl.2008.0526 |pmid=18957359 |pmc=2657756 |volume=5 |issue=1 |pages=81–85}}</ref> One critical study claims that the study neglects other factors, such as body mass (heavier animals are more likely to get stuck than lighter ones), intelligence (some social animals, like the American lion, may have avoided the tar because they were better able to recognize the hazard), lack of visual and [[olfactory]] lures, the type of audio lure, and the length of the distress calls (the actual distress calls of the trapped prey animals would have lasted longer than the calls used in the study). The author of that study ponders what predators would have responded if the recordings were played in India, where the otherwise solitary tigers are known to aggregate around a single carcass.<ref>{{cite journal |last=Kiffner |first=C. |year=2009 |title=Coincidence or evidence: was the sabretooth cat ''Smilodon'' social? |journal=Biology Letters |doi=10.1098/rsbl.2009.0008 |pmid=19443504 |pmc=2781900 |volume=5 |issue=4 |pages=561–562}}</ref> The authors of the original study responded that though effects of the calls in the tar pits and the playback experiments would not be identical, this would not be enough to overturn their conclusions. In addition, they stated that weight and intelligence would not likely affect the results as lighter carnivores are far more numerous than heavy herbivores and the social (and seemingly intelligent) dire wolf is also found in the pits.<ref>{{cite journal |last1=Van Valkenburgh |first1=B. |last2=Maddox |first2=T. |last3=Funston |first3=P. J. |last4=Mills |first4=M. G. L. |last5=Grether |first5=G. F. |last6=Carbone |first6=C. |year=2009 |title=Sociality in Rancho La Brea ''Smilodon'': arguments favour 'evidence' over 'coincidence' |journal=Biology Letters |doi=10.1098/rsbl.2009.0261 |volume=5 |issue=4 |pages=563–564|pmc=2781931 }}</ref>
[[File:Lions hunting a buffalo.jpg|thumb|right|[[Lion]] pride attacking an [[African buffalo]] in [[Tanzania]]; ''Smilodon'' may also have hunted in groups]]
Another argument for sociality is based on the healed injuries in several ''Smilodon'' fossils, which would suggest that the animals needed others to provide them food.<ref>{{cite journal |last=Heald |first=F. |year=1989 |title="Injuries and diseases in ''Smilodon californicus'' Bovard, 1904, (Mammalia, Felidae) from Rancho La Brea, California |journal=Journal of Vertebrate Paleontology |volume=9 |issue=3 |page=24A}}</ref><ref name="dysplasia">{{cite bioRxiv |last1=Balisi |first1=M. A. |last2=Sharma |first2=A. K. |last3=Howard |first3=C. M. |last4=Shaw |first4=C. A. |last5=Klapper |first5=R. |last6=Lindsey |first6=Emily L. |title=Computed tomography reveals hip dysplasia in Smilodon: Implications for social behavior in an extinct Pleistocene predator |date=2020 |biorxiv=10.1101/2020.01.07.897348}}</ref> This argument has been questioned, as cats can recover quickly from even severe bone damage and an injured ''Smilodon'' could survive if it had access to water.<ref name="McCall">{{cite journal |last1=McCall |first1=S. |last2=Naples |first2=V. |last3=Martin |first3=L. |year=2003 |title=Assessing behavior in extinct animals: was ''Smilodon'' social? |journal=Brain, Behavior and Evolution |pmid=12697957 |doi=10.1159/000069752 |volume=61 |issue=3 |pages=159–164|s2cid=2756104 |url=https://zenodo.org/record/1235325 }}</ref> However, a ''Smilodon'' suffering hip dysplasia at a young age that survived to adulthood suggests that it could not have survived to adulthood without aid from a social group, as this individual was unable to hunt or defend its territory due to the severity of its congenital issue.<ref>{{Cite journal|url=https://www.biorxiv.org/content/10.1101/2020.01.07.897348v2.full|doi = 10.1101/2020.01.07.897348|title = Computed tomography reveals hip dysplasia in the extinct Pleistocene saber-tooth cat Smilodon|year = 2021|last1 = Balisi|first1 = Mairin A.|last2 = Sharma|first2 = Abhinav K.|last3 = Howard|first3 = Carrie M.|last4 = Shaw|first4 = Christopher A.|last5 = Klapper|first5 = Robert|last6 = Lindsey|first6 = Emily L.|journal = bioRxiv|volume = 11|issue = 1|page = 21271|pmid = 34711910|pmc = 8553773|s2cid = 235663241}}</ref> The brain of ''Smilodon'' was relatively small compared to other cat species. Some researchers have argued that ''Smilodon''{{'s}} brain would have been too small for it to have been a social animal.<ref name="Radinsky">{{cite journal |last=Radinsky |first=L. B. |year=1975 |title=Evolution of the felid brain |journal=Brain, Behavior and Evolution |doi=10.1159/000123636 |pmid=1181005 |volume=11 |issue=3–4 |pages=214–254}}</ref> An analysis of brain size in living big cats found no correlation between brain size and sociality.<ref>{{cite journal |last1=Yamaguchi |first1=N. |last2=Kitchener |first2=A. C. |last3=Gilissen |first3=E. |last4=MacDonald |first4=D. W. |year=2009 |title=Brain size of the lion (''Panthera leo'') and the tiger (''P. tigris''): implications for intrageneric phylogeny, intraspecific differences and the effects of captivity |journal=Biological Journal of the Linnean Society |doi=10.1111/j.1095-8312.2009.01249.x |volume=98 |issue=1 |pages=85–93|doi-access= }}</ref> Another argument against ''Smilodon'' being social is that being an ambush hunter in closed habitat would likely have made group-living unnecessary, as in most modern cats.<ref name="McCall" /> Yet it has also been proposed that being the largest predator in an environment comparable to the savanna of Africa, ''Smilodon'' may have had a social structure similar to modern lions, which possibly live in groups primarily to defend optimal territory from other lions (lions are the only social big cats today).{{Sfn|Antón|2013|pp=176–216}}
[[File:La Brea Tar Pits Museum Injuries Exhibit.jpg|thumb|left|Tip of an ''S. fatalis'' saber imbedded in the rib of another ''S. fatalis'']]
Whether ''Smilodon'' was sexually dimorphic has implications for its reproductive behavior. Based on their conclusions that ''Smilodon fatalis'' had no sexual dimorphism, Van Valkenburgh and Sacco suggested in 2002 that, if the cats were social, they would likely have lived in [[Monogamous pairing in animals|monogamous pairs]] (along with offspring) with no intense competition among males for females.<ref name="Van Valenburgh" /> Likewise, Meachen-Samuels and Binder concluded in 2010 that aggression between males was less pronounced in ''S.&nbsp;fatalis'' than in the American lion.<ref name="Meachen-Samuels" /> Christiansen and Harris found in 2012 that, as ''S.&nbsp;fatalis'' did exhibit some sexual dimorphism, there would have been evolutionary selection for competition between males.<ref name="Christiansen" /> Some bones show evidence of having been bitten by other ''Smilodon'', possibly the result of territorial battles, competition for breeding rights or over prey.{{Sfn|Antón|2013|pp=176–216}} Two ''S. populator'' skulls from Argentina show seemingly fatal, unhealed wounds which appear to have been caused by the canines of another ''Smilodon'' (though it cannot be ruled out they were caused by kicking prey). If caused by intraspecific fighting, it may also indicate that they had social behavior which could lead to death, as seen in some modern felines (as well as indicating that the canines could penetrate bone).<ref name="Chimento2019">{{cite journal|last1= Chimento|first1=N. R.|last2= Agnolin|first2=F. L.|last3= Soibelzon|first3= L.|last4= Ochoa|first4=J. G.|last5= Buide|first5= V.|title= Evidence of intraspecific agonistic interactions in ''Smilodon populator'' (Carnivora, Felidae)|journal= Comptes Rendus Palevol|volume=18|issue=4|pages=449–454|year= 2019|doi= 10.1016/j.crpv.2019.02.006|bibcode=2019CRPal..18..449C |doi-access= free}}</ref> It has been suggested that the exaggerated canines of saber-toothed cats evolved for [[sexual display]] and competition, but a statistical study of the correlation between canine and body size in ''S. populator'' found no difference in scaling between body and canine size concluded it was more likely they evolved solely for a predatory function.<ref>{{cite journal |last1=O’Brien |first1=D. M |title=Static scaling and the evolution of extreme canine size in a saber-toothed cat (''Smilodon fatalis'') |journal=Integrative and Comparative Biology |volume=59 |issue=5 |pages=1303–1311 |date=2019 |doi=10.1093/icb/icz054|pmid=31120517 |doi-access=free }}</ref>
A set of three associated skeletons of ''S. fatalis'' found in Ecuador and described in 2021 by Reynolds, Seymour, and Evans suggests that there was prolonged parental care in ''Smilodon''. The two subadult individuals uncovered share a unique inherited trait in their dentaries, suggesting they were siblings; a rare instance of familial relationships being found in the fossil record. The subadult specimens are also hypothesized to have been male and female, respectively, while the adult skeletal remains found at the site are believed to have belonged to their mother. The subadults were estimated to have been around two years of age at the time of their deaths, but were still growing.<ref name="Reynolds, Seymour, and Evans 2021" /> ''S. fatalis'' had proportionally larger [[hyoid bone]]s than modern felid species and thus likely produced deeper vocalizations. While ''Smilodon'' had the same number of hyoid bones as the "[[roaring]]" cats, their shape was closer to that of "[[purr]]ing" species.<ref name=Deuthsch>{{cite journal|last1=Deutsch|first1=A. R.|last2=Langerhans|first2=R. B.|last3=Flores|first3=D|last4=Hartstone-Rose|first4=A|year=2023|title=The roar of Rancho La Brea? Comparative anatomy of modern and fossil felid hyoid bones|journal=Journal of Morphology|volume=284|issue=10|page=e21627|doi=10.1002/jmor.21627|pmid=37708512 |s2cid=261090355 |doi-access=free}}</ref>
=== Development ===
[[File:Smilodon canine replacement.jpg|thumb|Undersides of ''S. fatalis'' skulls, showing canine replacement, [[George C. Page Museum]]]]
''Smilodon'' started developing its adult saber-teeth when the animal reached between 12 and 19 months of age, shortly after the completion of the eruption of the cat's [[baby teeth]]. Both baby and adult canines would be present side by side in the mouth for an approximately 11-month period, and the muscles used in making the powerful bite were developed at about one-and-a-half years old as well, eight months earlier than in a modern lion. After ''Smilodon'' reached 23 to 30 months of age, the infant teeth were shed while the adult canines grew at an average growth rate of {{cvt|7|mm}} per month during a 12-month period. They reached their full size at around 3 years of age, later than modern species of big cats. Juvenile and adolescent ''Smilodon'' specimens are extremely rare at Rancho La Brea, where the study was performed, indicating that they remained hidden or at denning sites during hunts, and depended on parental care while their canines were developing.<ref name="SD2015.07.01">{{cite web |date=2015-07-01 |title=Dagger-like canines of saber-toothed cats took years to grow |website=[[ScienceDaily]] |url=https://www.sciencedaily.com/releases/2015/07/150701151821.htm |access-date=2015-07-02 |archive-url=https://web.archive.org/web/20150702152240/https://www.sciencedaily.com/releases/2015/07/150701151821.htm |archive-date=2015-07-02}}</ref><ref name="Mihlbachler2015">{{cite journal |last1=Mihlbachler |first1=M. C. |last2=Wysocki |first2=M. A. |last3=Feranec |first3=R. S. |last4=Tseng |first4=Z. J. |last5=Bjornsson |first5=C. S. |date=2015-07-01 |title=Using a novel absolute ontogenetic age determination technique to calculate the timing of tooth eruption in the saber-toothed cat, ''Smilodon fatalis'' |journal=PLOS ONE |doi=10.1371/journal.pone.0129847 |pmid=26132165 |bibcode=2015PLoSO..1029847W |pmc=4489498 |volume=10 |issue=7 |pages=e0129847|doi-access=free }} {{open access}}</ref><ref>{{cite journal |last=Feranec |first=R. C. |year=2004 |title=Isotopic evidence of saber-tooth development, growth rate, and diet from the adult canine of ''Smilodon fatalis'' from Rancho La Brea |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |doi=10.1016/j.palaeo.2004.01.009 |volume=206 |issue=3–4 |pages=303–310|bibcode=2004PPP...206..303F }}</ref>
A 2024 study found evidence that adolescent ''Smilodon'' kept their milk sabers for extended periods (estimated at 30 months) to help reinforce their adult canines as they grew in. As a result, the milk sabers acted as a structural support, allowing them to begin hunting with minimized risk to their mature set of sabers. As a result, the retention of the cat's milk sabers lessened the bending strain on the cat's emerging adult teeth as it bit down, as it was discovered the erupting sabers were much more vulnerable to breakage as they grew in than when matured. This would have also resulted in ''Smilodon'' being "double-fanged" during this growth stage, as corroborated by the discovery of individuals at this ontogenic stage at Rancho La Brea.<ref>{{cite journal |last1= Tseng |first1= Z.J. |date= April 2024 |title= Bending performance changes during prolonged canine eruption in saber-toothed carnivores: A case study of ''Smilodon fatalis'' |journal= The Anatomical Record |volume=  307 |issue= 5 |pages= |doi= 10.1002/ar.25447|doi-access= free |pmid= 38588019 }}</ref>
A 2017 study indicates that juveniles were born with a robust build similar to the adults. Comparison of the bones of juvenile ''S. fatalis'' specimens from La Brea with those of the contemporaneous American lion revealed that the two cats shared a similar growth curve. Felid forelimb development during [[ontogeny]] (changes during growth) has remained tightly constrained. The curve is similar to that for modern cats such as tigers and cougars, but shifts more towards the robust direction of the axes than is seen in modern felids.<ref>{{cite journal|last1=Long|first1=K.|last2=Prothero|first2=D.|last3=Madan|first3=M.|last4=Syverson|first4=V. J. P.|last5=Smith|first5=T.|title=Did saber-tooth kittens grow up musclebound? A study of postnatal limb bone allometry in felids from the Pleistocene of Rancho La Brea|journal=PLOS ONE|date=2017|volume=12|issue=9|pages=e0183175|doi=10.1371/journal.pone.0183175|pmid=28953899|pmc=5617143|bibcode=2017PLoSO..1283175L|doi-access=free}}</ref> Examinations by Reynolds, Seymour, and Evans (2021) suggest that ''Smilodon'' had a unique and fast growth rate similar to a tiger, but that there was a prolonged period of growth in the genus similar to what is seen in lions, and that the cubs were reliant on their parents until this growth period ended.<ref name="Reynolds, Seymour, and Evans 2021">{{Cite journal|title=Smilodon fatalis siblings reveal life history in a saber-toothed cat|date=January 7, 2021|journal=iScience|pages=101916|doi=10.1016/j.isci.2020.101916|doi-access=free|last1=Reynolds|first1=Ashley R.|last2=Seymour|first2=Kevin L.|last3=Evans|first3=David C.|volume=24|issue=1|pmid=33532710|pmc=7835254|bibcode=2021iSci...24j1916R}}</ref>
=== Paleopathology ===
[[File:Smilodon subchondral defects.PNG|thumb|left|Large [[subchondral defects]] in ''S. fatalis'' limb-joints (arrows)]]
Several ''Smilodon'' fossils show signs of [[ankylosing spondylitis]], [[hyperostosis]] and trauma.<ref name="Bjorkengren">{{cite journal |last1=Bjorkengren |first1=A. G. |last2=Sartoris |first2=D. J. |last3=Shermis |first3=S. |last4=Resnick |first4=D. |year=1987 |title=Patterns of paravertebral ossification in the prehistoric saber-toothed cat |journal=American Journal of Roentgenology |pmid=3103404 |doi=10.2214/ajr.148.4.779 |volume=148 |issue=4 |pages=779–782|doi-access= }}</ref> One study of 1,000 ''Smilodon'' skulls found that 36% of them had eroded [[parietal bone]]s, which is where the largest jaw muscles attach. They also showed signs of microfractures, and the weakening and thinning of bones possibly caused by mechanical stress from the constant need to make stabbing motions with the canines.<ref>{{cite journal |last=Duckler |first=G. L. |year=1997 |title=Parietal depressions in skulls of the extinct saber-toothed felid ''Smilodon fatalis'': evidence of mechanical strain |journal=Journal of Vertebrate Paleontology |doi=10.1080/02724634.1997.10011006 |volume=17 |issue=3 |pages=600–609|bibcode=1997JVPal..17..600D }}</ref> Bony growths where the [[deltoid muscle]] inserted in the humerus is a common pathology for a La Brea specimen, which was probably due to repeated strain when ''Smilodon'' attempted to pull down prey with its forelimbs. Sternum injuries are also common, probably due to collision with prey.{{Sfn|Antón|2013|p=199}}
The frequency of trauma in ''S. fatalis'' specimens was 4.3%, compared to 2.8% in the dire wolf, which implies the ambush predatory behavior of the former led to greater risk of injury than the pursuit predatory behavior of the latter. ''Smilodon'' remains exhibit relatively more shoulder and [[lumbar vertebrae]] injuries.<ref>{{cite journal|last1=Brown|first1=C.|last2=Balisi|first2=M.|last3=Shaw|first3=C. A.|last4=Van Valkenburgh|first4=B.|title=Skeletal trauma reflects hunting behaviour in extinct sabre-tooth cats and dire wolves|journal=Nature Ecology & Evolution|date=2017|volume=1|issue=5|pages=0131|doi=10.1038/s41559-017-0131|pmid=28812696|bibcode=2017NatEE...1..131B |s2cid=8008808}}</ref> A 2023 study documented a high degree of [[subchondral defects]] in limb-joint surfaces of ''S. fatalis'' and dire wolf specimens from the La Brea Tar pits that resembled [[osteochondrosis dissecans]]. As modern dogs with this disease are [[inbred]], the researchers suggested this would have been the case for the prehistoric species as well as they approached extinction, but cautioned that more research was needed to determine if this was also the case in specimens from other parts of the Americas.<ref name="Subchondral defects">{{cite journal |last1=Schmökel |first1=Hugo |last2=Farrell |first2=Aisling |last3=Balisi |first3=Mairin F. |title=Subchondral defects resembling osteochondrosis dissecans in joint surfaces of the extinct saber-toothed cat ''Smilodon fatalis'' and dire wolf ''Aenocyon dirus'' |journal=PLOS ONE |date=2023 |volume=18 |issue=7 |pages=e0287656 |doi=10.1371/journal.pone.0287656|pmid=37436967 |pmc=10337945 |bibcode=2023PLoSO..1887656S |doi-access=free }}</ref>
[[Osteomyelitis]] in the left [[fourth metacarpal bone]] has been reported in a ''S. populator'' specimen dating back to [[Marine Isotope Stage 5]]. This pathology resulted in the machairodont individual becoming incapable of flexing its toe and would have severely diminished its ability to hunt prey.<ref>{{Cite journal |last1=Luna |first1=Carlos A. |last2=Pool |first2=Roy R. |last3=Ercoli |first3=Marcos D. |last4=Chimento |first4=Nicolás R. |last5=Barbosa |first5=Fernando H. de S. |last6=Zurita |first6=Alfredo E. |last7=Cuaranta |first7=Pedro |date=22 May 2023 |title=Osteomyelitis in the manus of Smilodon populator (Felidae, Machairodontinae) from the Late Pleistocene of South America |url=https://www.sciencedirect.com/science/article/pii/S1871174X23000471 |journal=[[Palaeoworld]] |volume=33 |issue=2 |pages=517–525 |doi=10.1016/j.palwor.2023.05.001 |issn=1871-174X |access-date=5 February 2024 |via=Elsevier Science Direct}}</ref>
== Distribution and habitat ==
[[File:Paleontological landscape painting, White Sands National Park, United States.jpg|left|thumb|alt=Painting of animals around a lake|Environment of what is now [[White Sands National Park]], with ''S. fatalis'' in the reeds in the right foreground]]
''Smilodon'' lived during the [[Pleistocene]] epoch (2.5 mya–10,000 years ago), and was perhaps the most recent of the saber-toothed cats.<ref name="Turner" /> ''S. fatalis'' lived in a variety of habitats, being able to inhabit open grassland and parkland,<ref>{{Cite journal |last1=Hill |first1=Matthew G. |last2=Easterla |first2=David A. |date=1 May 2023 |title=A complete sabertooth cat cranium from the Midcontinent of North America and its evolutionary and ecological context |url=https://linkinghub.elsevier.com/retrieve/pii/S0277379123000938 |journal=[[Quaternary Science Reviews]] |language=en |volume=307 |pages=108045 |doi=10.1016/j.quascirev.2023.108045 |bibcode=2023QSRv..30708045H |access-date=27 April 2024 |via=Elsevier Science Direct}}</ref> marginal woodland-grassland settings,<ref>{{Cite journal |last1=Kohn |first1=Matthew J. |last2=McKay |first2=Moriah P. |last3=Knight |first3=James L. |date=1 August 2005 |title=Dining in the Pleistocene—Who's on the menu? |url=https://pubs.geoscienceworld.org/gsa/geology/article/33/8/649/103783/Dining-in-the-PleistoceneWhos-on-the-menu |journal=[[Geology (journal)|Geology]] |language=en |volume=33 |issue=8 |pages=649–652 |doi=10.1130/G21476AR.1 |issn=1943-2682 |access-date=27 April 2024 |via=GeoScienceWorld}}</ref> and closed forests.<ref>{{Cite journal |last1=Schellhorn |first1=Rico |last2=Sanmugaraja |first2=Mayuran |date=16 April 2014 |title=Habitat adaptations in the felid forearm |url=http://link.springer.com/10.1007/s12542-014-0230-8 |journal=[[PalZ]] |language=en |volume=89 |issue=2 |pages=261–269 |doi=10.1007/s12542-014-0230-8 |issn=0031-0220 |access-date=27 April 2024 |via=Springer}}</ref> Fossils of the genus have been found throughout the Americas.<ref name="Status" /> The northernmost remains of the genus are ''S. fatalis'' fossils from [[Alberta, Canada]],<ref name="Canada">{{cite journal |last1=Reynolds |first1=A. R. |last2=Seymour |first2=K. L. |last3=Evans |first3=D. C. |title=Late Pleistocene records of felids from Medicine Hat, Alberta, including the first Canadian record of the sabre-toothed cat Smilodon fatalis |journal=Canadian Journal of Earth Sciences |date=2019 |volume=56 |issue=10 |pages=1052–1060 |doi=10.1139/cjes-2018-0272|bibcode=2019CaJES..56.1052R |hdl=1807/96725 |s2cid=134586651 |hdl-access=free }}</ref> with the southernmost remains of ''S. populator'' being known from the far south of [[Patagonia]], near the [[Strait of Magellan]].<ref>{{Cite journal |last1=Villavicencio |first1=Natalia A. |last2=Lindsey |first2=Emily L. |last3=Martin |first3=Fabiana M. |last4=Borrero |first4=Luis A. |last5=Moreno |first5=Patricio I. |last6=Marshall |first6=Charles R. |last7=Barnosky |first7=Anthony D. |date=February 2016 |title=Combination of humans, climate, and vegetation change triggered Late Quaternary megafauna extinction in the Última Esperanza region, southern Patagonia, Chile |url=https://onlinelibrary.wiley.com/doi/10.1111/ecog.01606 |journal=Ecography |language=en |volume=39 |issue=2 |pages=125–140 |doi=10.1111/ecog.01606 |bibcode=2016Ecogr..39..125V |issn=0906-7590}}</ref> The habitat of North America varied from subtropical forests and savannah in the south, to treeless [[mammoth steppes]] in the north. The mosaic vegetation of woods, shrubs, and grasses in southwestern North America supported large herbivores such as horses, bison, [[Antilocapridae|antelope]], [[deer]], camels, [[mammoth]]s, [[mastodon]]s, and [[ground sloth]]s. North America also supported other saber-toothed cats, such as ''Homotherium'' and ''Xenosmilus'', as well as other large carnivores including dire wolves, [[Arctodus|short-faced bear]] (''Arctodus simus'') and the American lion.{{Sfn|Antón|2013|pp=65–76}}{{Sfn|Antón|2013|pp=30–33}}<ref name=desantis2015>{{cite journal|last1=DeSantis|first1=L.R.G.|last2=Schubert|first2=B.W.|last3=Schmitt-Linville|first3=E.|last4=Ungar|first4=P.|last5=Donohue|first5=S.|last6=Haupt|first6=R.J.|title=Dental microwear textures of carnivorans from the La Brea Tar Pits, California and potential extinction implications|publisher=Natural History Museum of Los Angeles County|journal=Science Series 42: Contributions in Science |issue=A special volume entitled La Brea and Beyond: the Paleontology of Asphalt–Preserved Biotas in commemoration of the 100th anniversary of the Natural History Museum of Los Angeles County's excavations at Rancho La Brea|editor=John M. Harris|date=September 15, 2015|pages=37–52|url=http://www.nhm.org/site/sites/default/files/pdf/contrib_science/lacm-42.pdf|access-date=February 6, 2017|archive-url=https://web.archive.org/web/20161220065852/http://www.nhm.org/site/sites/default/files/pdf/contrib_science/lacm-42.pdf|archive-date=December 20, 2016|url-status=dead}}</ref> Competition from such carnivores may have prevented North American ''S.&nbsp;fatalis'' from attaining the size of South America's ''S.&nbsp;populator''. The similarity in size of ''S.&nbsp;fatalis'' and the American lion suggests niche overlap and direct competition between these species, and they appear to have fed on similarly sized prey.<ref name="Felidmass" />
[[File:Great American Biotic Interchange examples.svg|thumb|right|Animals that participated in the [[Great American Interchange]], with North American migrants like ''S.&nbsp;populator'' (lower right) in blue]]
''S. gracilis'' entered South America during the early to middle Pleistocene, where it probably gave rise to ''S.&nbsp;populator'', which lived in the eastern part of the continent. ''S.&nbsp;fatalis'' also entered western South America in the late Pleistocene, and the two species were thought to be divided by the [[Andes mountains]].<ref name=Kurten /><ref name="Rincón2011" /><ref name="Turner" /> However, in 2018, a skull of ''S.&nbsp;fatalis'' found in [[Uruguay]] east of the Andes was reported, which puts the idea that the two species were [[allopatric]] (geographically separated) into question.<ref name="Manzuetti2018">{{cite journal|doi=10.1016/j.quascirev.2017.11.024|title=First record of ''Smilodon fatalis'' Leidy, 1868 (Felidae, Machairodontinae) in the extra-Andean region of South America (late Pleistocene, Sopas Formation), Uruguay: Taxonomic and paleobiogeographic implications |journal=[[Quaternary Science Reviews]] |volume= 180|pages= 57–62|year= 2018|last1= Manzuetti|first1= A.|last2= Perea|first2= D.|last3= Ubilla|first3= M.|last4= Rinderknecht|first4= A. |bibcode=2018QSRv..180...57M }}</ref> The American interchange resulted in a mix of native and [[invasive species]] sharing the prairies and woodlands in South America; North American herbivores included proboscideans, horses, [[camelid]]s and deer, South American herbivores included toxodonts, litopterns, ground sloths, and glyptodonts. Native [[metatherian]] predators (including the saber-toothed thylacosmilids, which do not appear to have competed with ''Smilodon'') had gone extinct by the Pliocene, and were replaced by North American carnivores such as canids, bears, and large cats.{{Sfn|Antón|2013|pp=65–76}}<ref name="NoNicheCompetition">{{cite journal |last1=Freitas-Oliveira |first1=Roniel |last2=Lima-Ribeiro |first2=Matheus S. |last3=Terribile |first3=Levi Carina |title=No evidence for niche competition in the extinction of the South American saber-tooth species |journal=npj Biodiversity |date=2024 |volume=3 |issue=1 |page=11 |doi=10.1038/s44185-024-00045-7|pmid=39242707 |pmc=11332042 |bibcode=2024npjBD...3...11F }}</ref>
''S.&nbsp;populator'' was very successful, while ''Homotherium'' never became widespread in South America. The extinction of the thylacosmilids has been attributed to competition with ''Smilodon'', but this is probably incorrect, as they seem to have disappeared before the arrival of the large cats. The [[phorusrhacid]] "terror birds" may have dominated the large predator niche in South America until ''Smilodon'' arrived.{{Sfn|Antón|2013|pp=65–76}} ''S. populator'' may have been able to reach larger size than ''S. fatalis'' due to a lack of competition in Pleistocene South America; ''S. populator'' arrived after the extinction of ''[[Arctotherium angustidens]]'', one of the largest carnivores ever, and could therefore assume the niche of mega-carnivore.<ref name="Felidmass">Sherani, S. (2016). ''A new specimen-dependent method of estimating felid body mass (No. e2327v2)''. PeerJ Preprints.</ref> ''S. populator'' preferred large prey from open habitats such as grassland and plains, based on evidence gathered from isotope ratios that determined the animal's diet. In this way, the South American ''Smilodon'' species was probably similar to the modern lion. ''S. populator'' probably competed with the canid ''[[Protocyon]]'' there, but not with the jaguar, which fed primarily on smaller prey.<ref name="Bocherens2016">{{cite journal |last1=Bocherens |first1=H. |last2=Cotte |first2=M. |last3=Bonini |first3=R. |last4=Scian |first4=D. |last5=Straccia |first5=P. |last6=Soibelzon |first6=L. |last7=Prevosti |first7=F. J. |date=2016-04-24 |title=Paleobiology of sabretooth cat ''Smilodon population'' in the Pampean Region (Buenos Aires Province, Argentina) around the Last Glacial Maximum: Insights from carbon and nitrogen stable isotopes in bone collagen |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |doi=10.1016/j.palaeo.2016.02.017 |volume=449 |pages=463–474|bibcode=2016PPP...449..463B |hdl=11336/43965 |hdl-access=free }}</ref><ref>{{cite web |last=Hays |first=B. |date=2016-03-21 |title=Saber-toothed cats were the lions of prehistoric South America |website=UPI Science News |publisher=UPI |url=http://www.upi.com/Science_News/2016/03/21/Saber-toothed-cats-were-the-lions-of-prehistoric-South-America/1841458566285/ |access-date=19 April 2016}}</ref> On the other hand, morphometry points to ''S. populator'' being best adapted for more closed environments.<ref>{{Cite journal |last1=Meloro |first1=Carlo |last2=Elton |first2=Sarah |last3=Louys |first3=Julien |last4=Bishop |first4=Laura C. |last5=Ditchfield |first5=Peter |date=18 March 2013 |title=Cats in the forest: predicting habitat adaptations from humerus morphometry in extant and fossil Felidae (Carnivora) |url=https://www.cambridge.org/core/journals/paleobiology/article/abs/cats-in-the-forest-predicting-habitat-adaptations-from-humerus-morphometry-in-extant-and-fossil-felidae-carnivora/AB965A6E897A798DFE053AE125CDF730 |journal=[[Paleobiology (journal)|Paleobiology]] |language=en |volume=39 |issue=3 |pages=323–344 |doi=10.1666/12001 |bibcode=2013Pbio...39..323M |issn=0094-8373 |access-date=21 January 2024 |via=Cambridge Core}}</ref>
== Extinction ==
[[File:Panthera leo atrox and Smilodon fatalis Page.jpg|thumb|left|Skeletons of ''S. fatalis'' (left) and the [[American lion]], two large North American [[felids]] which went [[extinct]] during the [[Late Pleistocene]], George C. Page Museum]]
Along with most of the New World Pleistocene megafauna, ''Smilodon'' became extinct by 10,000 years ago in the [[Late Pleistocene extinctions|late Pleistocene extinction phases of North and South America]]. Its extinction has been linked to the decline and extinction of large herbivores. Hence, ''Smilodon'' could have been too specialized at hunting large prey and may have been unable to adapt.<ref name=forelimbs />  Indeed, by the [[Bølling–Allerød warming]] event and before the [[Younger Dryas]] cooling event, ''S. fatalis'' showed changes in cranial morphology that hint towards increased specialization in larger prey and/or evolution in response to competition with other carnivores.<ref>{{cite journal|last1=Meachen|first1=Julie A.|last2=O'Keefe|first2=F. Robin|last3=Sadleir|first3=Rudyard W.|year=2014|title=Evolution in the sabre-tooth cat, Smilodon fatalis, in response to Pleistocene climate change|journal=Journal of Evolutionary Biology|volume=27|issue=4|pages=714–723|doi=10.1111/jeb.12340|pmid=24779050 }}</ref> However, a 2012 study of ''Smilodon'' tooth wear found no evidence that they were limited by food resources.<ref name=desantis2012>{{cite journal |last1=DeSantis |first1=L. R. G. |last2=Schubert |first2=B. W. |last3=Scott |first3=J. R. |last4=Ungar |first4=P. S. |year=2012 |title=Implications of diet for the extinction of saber-toothed cats and American lions |journal=PLOS ONE |doi=10.1371/journal.pone.0052453 |bibcode=2012PLoSO...752453D |volume=7 |issue=12 |page=e52453 |pmid=23300674 |pmc=3530457|doi-access=free }} {{open access}}</ref> Other explanations include climate change and competition with ''[[Homo sapiens]]''<ref name=desantis2012 /> (who entered the Americas around the time ''Smilodon'' disappeared), or a combination of several factors, all of which apply to the general [[Late Pleistocene extinctions|Late Pleistocene extinction event]], rather than specifically to the extinction of the saber-toothed cats.{{Sfn|Antón|2013|pp=217–230}} One factor often cited here is the cooling in the [[Younger Dryas]], which may have drastically reduced the habitable space for many species. In terms of human influence, there is evidence of a fire-induced regime change in Rancho la Brea that preceded the [[Local extinction|extirpation]] of megafauna in the area, with humans most likely responsible for the increase in fire intensity.<ref name="fire">{{cite journal|last1=O'Keefe|first1=F. Robin|last2=Dunn|first2=Regan E.|last3=Weitzel|first3=Elic M.|last4=Waters|first4=Michael R.|last5=Martinez|first5=Lisa N.|last6=Binder|first6=Wendy J.|last7=Southon|first7=John R.|last8=Cohen|first8=Joshua E.|last9=Meachen|first9=Julie A.|last10=DeSantis|first10=Larisa R. G.|last11=Kirby|first11=Matthew E.|last12=Ghezzo|first12=Elena|last13=Coltrain|first13=Joan B.|last14=Fuller|first14=Benjamin T.|last15=Farrell|first15=Aisling B.|last16=Takuechi|first16=Gary T.|last17=MacDonald|first17=Glen|last18=Davis|first18=Edward B.|last19=Lindsey|first19=Emily L.|year=2023|title=Pre–Younger Dryas megafaunal extirpation at Rancho La Brea linked to fire-driven state shift|journal=Science|volume=381|issue=6659|pages=eabo3594 |doi=10.1126/science.abo3594|pmid=37590347 }}</ref>
Writers of the first half of the twentieth century theorized that the last saber-toothed cats, ''Smilodon'' and ''Homotherium'', became extinct through competition with the faster and more generalized felids that replaced them. It was even proposed that the saber-toothed predators were inferior to modern cats, as the ever-growing canines were thought to inhibit their owners from feeding properly. Since then, however, it has been shown that the diet of machairodontines such as ''Smilodon'' and ''Homotherium'' was diverse. They do not seem to have been limited to giant animals as prey, as suggested before, but fed on whatever was available, including [[Bovinae|bovines]], [[Equus (genus)|equines]] and [[Camelidae|camelids]].<ref>{{Cite journal |last=Bocherens |first=Hervé |date=2015-06-01 |title=Isotopic tracking of large carnivore palaeoecology in the mammoth steppe |url=https://www.sciencedirect.com/science/article/pii/S0277379115001250 |journal=Quaternary Science Reviews |volume=117 |pages=42–71 |doi=10.1016/j.quascirev.2015.03.018 |bibcode=2015QSRv..117...42B |issn=0277-3791}}</ref><ref>{{Cite journal |last1=Prevosti |first1=Francisco J. |last2=Martin |first2=Fabiana M. |date=2013-08-14 |title=Paleoecology of the mammalian predator guild of Southern Patagonia during the latest Pleistocene: Ecomorphology, stable isotopes, and taphonomy |url=https://www.sciencedirect.com/science/article/pii/S1040618213000049 |journal=Quaternary International |series=Ranked habitats and the process of human colonization of South America |volume=305 |pages=74–84 |doi=10.1016/j.quaint.2012.12.039 |bibcode=2013QuInt.305...74P |issn=1040-6182|hdl=11336/84524 |hdl-access=free }}</ref> Additionally, non-machairodontine felids such as the American lion and ''[[Miracinonyx]]'' also became extinct during the Late Pleistocene, and saber-toothed and conical toothed felids had formerly coexisted for more than a million years.{{sfn|Antón|2013|p=223}} The fact that saber-teeth evolved many times in unrelated lineages also attests to the success of this feature.{{Sfn|Antón|2013|pp=217–230}}
The youngest direct radiocarbon date for ''S. fatalis'' differs from that of ''S. populator'' by thousands of years, the former just before the Younger Dryas cooling event and the latter by the early Holocene.<ref name="book">{{cite book|last=Stuart|first=Anthony J.|title=Vanished Giants: The Lost World of the Ice Age|chapter=Chapter 6. North America: mastodon, ground sloths, and sabertooth cats|date=August 20, 2022 |publisher=University of Chicago Press|pages=67–112 |isbn=978-0-226-82403-1}}</ref> The latest ''S. fatalis'' specimen recovered from the Rancho La Brea tar pits has been dated to 13,025 years ago.<ref>{{cite journal|last1=O'Keefe|first1=F.R.|last2=Fet|first2=E.V.|last3=Harris|first3=J.M.|title=Compilation, calibration, and synthesis of faunal and floral radiocarbon dates, Rancho La Brea, California|journal=Contributions in Science|volume=518|year=2009|pages=1–16|doi=10.5962/p.226783|s2cid=128107590|doi-access=free}}</ref> A specimen of ''S. fatalis'' from Iowa dates to 13,605–13,455 years [[Before Present]] (BP).<ref>{{Cite journal |last1=Hill |first1=Matthew G. |last2=Easterla |first2=David A. |date=May 2023 |title=A complete sabertooth cat cranium from the Midcontinent of North America and its evolutionary and ecological context |url=https://linkinghub.elsevier.com/retrieve/pii/S0277379123000938 |journal=Quaternary Science Reviews |language=en |volume=307 |pages=108045 |doi=10.1016/j.quascirev.2023.108045|bibcode=2023QSRv..30708045H |s2cid=257861663 }}</ref> The latest ''Smilodon populator'' remains found in the cave of Cueva del Medio, near the town of Soria, northeast [[Última Esperanza Province]], [[Magallanes Region]] in southernmost [[Chile]] have been dated to 10,935–11,209 years ago.<ref>{{cite journal|doi=10.4067/S0716-078X2010000200010|title=New evidence of the sabertooth cat Smilodon (Carnivora: Machairodontinae) in the late Pleistocene of southern Chilean Patagonia|journal=Revista Chilena de Historia Natural|volume=83|issue=2|year=2010|last1=Prieto|first1=Alfredo|last2=Labarca|first2=Rafael|last3=Sierpe|first3=Víctor|doi-access=free}}</ref> The most recent credible carbon-14 date for ''S. fatalis'' has been given as 11,130 BP.<ref name="Fiedal">{{Cite book | first = Stuart | last = Fiedel | series = Vertebrate Paleobiology and Paleoanthropology | editor-last = Haynes | editor-first = Gary | contribution = Sudden Deaths: The Chronology of Terminal Pleistocene Megafaunal Extinction | contribution-url = https://link.springer.com/content/pdf/10.1007%2F978-1-4020-8793-6.pdf | title = American Megafaunal Extinctions at the End of the Pleistocene | year = 2009 | pages = 21–37 | publisher = [[Springer Science+Business Media|Springer]] | doi = 10.1007/978-1-4020-8793-6_2 | isbn = 978-1-4020-8792-9 }}</ref> However, such radiocarbon dates are likely uncalibrated, meaning that they were not adjusted from calendar years to regular years. As a result, the dates appear younger than they actually are. Therefore, the ''S. fatalis'' specimen from Rancho La Brea is the youngest-recorded of the species,<ref name="book"/> suggesting extinction before the Younger Dryas based on its last appearance in California as opposed to other regions where megafauna declined by the Younger Dryas.<ref name="fire"/>
== See also ==
{{Portal|Biology|Paleontology}}
* [[List of largest carnivorans]]
* [[List of largest prehistoric carnivorans]]
* [[Megafauna]]
* [[Late Pleistocene extinctions]]
== References ==
{{Reflist}}
== Bibliography ==
{{Commons and category}}
{{Wikispecies|Smilodon}}
{{refbegin}}
* <!-- {{Sfn|Antón|2013}} -->{{cite book |last=Antón |first=M. |year=2013 |title=Sabertooth |edition=1st |publisher=Indiana University Press |location=Bloomington |isbn=978-0-253-01042-1 |oclc=857070029 |url=https://books.google.com/books?id=dVcqAAAAQBAJ}}
{{refend}}
{{Machairodontinae}}
{{Taxonbar|from1=Q188717|from2=Q1294271|from3=Q1956565|from4=Q3506463}}
{{authority control}}
[[Category:Smilodon| ]]
[[Category:Apex predators]]
[[Category:Holocene extinctions]]
[[Category:Fossil taxa described in 1842]]
[[Category:Prehistoric carnivoran genera]]
[[Category:Pleistocene carnivorans]]
[[Category:Pleistocene first appearances]]
[[Category:Pleistocene genus extinctions]]
[[Category:Pleistocene mammals of North America]]
[[Category:Pleistocene mammals of South America]]
[[Category:Smilodontini]]
[[Category:Taxa named by Peter Wilhelm Lund]]
[[Category:Sopas Formation]]
[[Category:Symbols of California]]