Editing Smilodon (section)

=== 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 by the sides due to their flattened shape 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" /> The bending force applied from the back to front of a ''S. fatalis'' upper canine required to break it, has been estimated to be of 7000 [[Newton (unit)|Newtons]], in comparison, in lions and tigers, two predators of similar size, a bending force of 8243 and 7440 Newtons, respectively, would be required.<ref>{{Cite journal |last=Freeman |first=P. W. |last2=Lemen |first2=C. |date=2007 |title=An experimental approach to modeling the strength of canine teeth |url=https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1012&context=natrespapers |journal=Journal of Zoology |language=en |volume=271 |issue=2 |pages=162–169 |doi=10.1111/j.1469-7998.2006.00194.x |issn=1469-7998|url-access=subscription }}</ref>

[[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 = Smilodon maximum gape.jpg
|alt1 =
|image2 = Smilodon gaping.jpg 
|alt2 =
|footer = ''S. fatalis'' skull with muscle reconstruction showing maximum gape (left) and restoration by [[Mauricio Antón]] 
}}
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> The supplementary materials of a 2020 study suggested ''S. gracilis'' and ''S. populator'' had a jaw gape of 89.13 and 82.05 degrees respectively.<ref name="InoBite">{{cite journal |last1=Lautenschlager |first1=Stephan |last2=Figueirido |first2=Borja |last3=Cashmore |first3=Daniel D. |last4=Bendel |first4=Eva-Maria |last5=Stubbs |first5=Thomas L. |year=2020 |title=Morphological convergence obscures functional diversity in sabre-toothed carnivores |journal=[[Proceedings of the Royal Society B]] |volume=287 |issue=1935 |pages=1–10 |doi=10.1098/rspb.2020.1818 |issn=1471-2954 |pmc=7542828 |pmid=32993469 |doi-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>