Editing Homotherium (section)

==Paleobiology and paleoecology ==
''Homotherium'' is suggested to have been adapted to hunting large prey.<ref name="antón 2022" /> The reduced claws, relatively slender and long limbs, and sloping back all appear to be adaptations for moderate-speed endurance running in open habitats.<ref name="anton etal 2005">{{Cite journal |last1=Anton |first1=M. |last2=Galobart |first2=A. |last3=Turner |first3=A. |date=May 2005 |title=Co-existence of scimitar-toothed cats, lions and hominins in the European Pleistocene. Implications of the post-cranial anatomy of (Owen) for comparative palaeoecology |journal=[[Quaternary Science Reviews]] |volume=24 |issue=10–11 |pages=1287–1301 |doi=10.1016/j.quascirev.2004.09.008}}</ref><ref name="antón 2022" /> The running-adapted morphology of its forelimbs suggests that they were less useful than those of ''Smilodon'' or many living big cats in grasping and restraining prey, and that the enlarged incisor teeth at the front of the jaws served an important role in prey restraint, like in hyenas and canids.<ref name="antón 2022" /> 
[[File:Homotherium biting sequence.jpg|thumb|Illustration of ''Homotherium'' performing a "canine shear bite" on a prey animal. Artwork by [[Mauricio Antón]].|402x402px]]
It has been suggested that ''Homotherium'' killed prey by slashing bites to the throat inflicted by its canines.<ref name="FigueiridoLautenschlager2018">{{cite journal |last1=Figueirido |first1=Borja |last2=Lautenschlager |first2=Stephan |last3=Pérez-Ramos |first3=Alejandro |last4=Van Valkenburgh |first4=Blaire |date=October 2018 |title=Distinct Predatory Behaviors in Scimitar- and Dirk-Toothed Sabertooth Cats |journal=Current Biology |volume=28 |issue=20 |pages=3260–3266.e3 |bibcode=2018CBio...28E3260F |doi=10.1016/j.cub.2018.08.012 |pmid=30293717 |doi-access=free |hdl-access=free |hdl=10630/29727}}</ref> Like other sabertooth cats, ''Homotherium'' is widely thought to have used a "canine shear bite" technique, where, once the prey was immobilized and the jaws opened around the throat of the prey, the neck muscles of ''Homotherium'' were used to force the skull and the saber canine teeth downwards (more specifically via a downward rotation of the skull) to puncture the throat of prey.<ref name=":4" /><ref>{{Cite journal |last1=Antón |first1=Mauricio |last2=Salesa |first2=Manuel J. |last3=Pastor |first3=Juan Francisco |last4=Sánchez |first4=Israel M. |last5=Fraile |first5=Susana |last6=Morales |first6=Jorge |date=February 2004 |title=Implications of the mastoid anatomy of larger extant felids for the evolution and predatory behaviour of sabretoothed cats (Mammalia, Carnivora, Felidae) |url=https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2003.00093.x |journal=Zoological Journal of the Linnean Society |language=en |volume=140 |issue=2 |pages=207–221 |doi=10.1111/j.1096-3642.2003.00093.x |issn=1096-3642}}</ref><ref name=":9">{{Cite journal |last1=Antón |first1=Mauricio |last2=Siliceo |first2=Gema |last3=Pastor |first3=Juan Francisco |last4=Morales |first4=Jorge |last5=Salesa |first5=Manuel J |date=2020-01-01 |title=The early evolution of the sabre-toothed felid killing bite: the significance of the cervical morphology of Machairodus aphanistus (Carnivora: Felidae: Machairodontinae) |url=https://academic.oup.com/zoolinnean/article/188/1/319/5581941 |journal=Zoological Journal of the Linnean Society |language=en |volume=188 |issue=1 |pages=319–342 |doi=10.1093/zoolinnean/zlz086 |issn=0024-4082}}</ref> These throat bites would likely have caused massive blood loss resulting in rapid death.<ref name=":4" /><ref name=":3">{{Cite journal |last1=Turner |first1=A. |last2=Antón |first2=M. |last3=Salesa |first3=M. J. |last4=Morales |first4=J. |date=2011-12-30 |title=Changing ideas about the evolution and functional morphology of Machairodontine felids |url=https://www.researchgate.net/publication/235349543 |journal=Estudios Geológicos |volume=67 |issue=2 |pages=255–276 |doi=10.3989/egeol.40590.188 |issn=1988-3250|doi-access=free }}</ref> The elongate and strong neck likely allowed fine control enabling the head to be precisely located, orientated and held in position for the bite.<ref name=":4">{{Cite journal |last1=Antón |first1=Mauricio |last2=Galobart |first2=Àngel |date=1999-12-13 |title=Neck function and predatory behavior in the scimitar toothed cat Homotherium latidens (Owen) |url=http://www.tandfonline.com/doi/abs/10.1080/02724634.1999.10011190 |journal=Journal of Vertebrate Paleontology |language=en |volume=19 |issue=4 |pages=771–784 |doi=10.1080/02724634.1999.10011190 |bibcode=1999JVPal..19..771A |issn=0272-4634}}</ref><ref name=":9" /> However, some recent authors have suggested that its style of prey restraint was probably different to that of ''Smilodon'' (which had more powerful forelimbs which helped to better restrain prey) with a killing technique more similar in some aspects to the [[Muzzle clamp|clamp-and-hold]] technique used by living big cats like lions, with the saber teeth of ''Homotherium'' better able to resist sideways directed forces induced by struggling prey without fracturing than those of ''Smilodon.<ref name="FigueiridoLautenschlager2018" />'' Dental microwear analysis of specimens of ''H. serum'' from North America suggests that ''Homotherium'' regularly consumed tough-fleshed prey, but only engaged in defleshing and did not engage in bone crunching/crushing, similar to cheetahs but unlike living lions and hyenas.<ref name="desantis etal 2021" />

It has been speculated based on its adaptation to open habitats and high levels of competition from other carnivores, that ''Homotherium'' probably relied on group hunting, which would make it easier to take down prey to compensate for their relatively weak forelimbs, increase the size of prey able to be taken, and enable distraction strategies to be employed during hunting, as well as to be better able to defend kills against [[kleptoparasitism]] by other carnivores.<ref name="antón 2022" />

Analysis of the genome of a ''Homotherium'' specimen found in permafrost in [[Yukon]] in northern Canada, suggests that ''Homotherium'' experienced positive selection for genes related to respiration and the circulatory system, which may have been adaptations for endurance running. Positive selection for genes related to vision indicates that sight probably played an important role in hunting, suggesting that ''Homotherium'' was a [[Diurnality|diurnal]] (daytime) hunter. Selection for genes related to cognition were tentatively suggested by researchers to possibly support the social hunting hypothesis.<ref>{{cite journal |last1=Barnett |first1=Ross |last2=Westbury |first2=Michael V. |last3=Sandoval-Velasco |first3=Marcela |last4=Vieira |first4=Filipe Garrett |last5=Jeon |first5=Sungwon |last6=Zazula |first6=Grant |last7=Martin |first7=Michael D. |last8=Ho |first8=Simon Y. W. |last9=Mather |first9=Niklas |last10=Gopalakrishnan |first10=Shyam |last11=Ramos-Madrigal |first11=Jazmín |last12=Manuel |first12=Marc de |last13=Zepeda-Mendoza |first13=M. Lisandra |last14=Antunes |first14=Agostinho |last15=Baez |first15=Aldo Carmona |date=21 December 2020 |title=Genomic Adaptations and Evolutionary History of the Extinct Scimitar-Toothed Cat, Homotherium latidens |journal=[[Current Biology]] |volume=30 |issue=24 |pages=5018–5025.e5 |bibcode=2020CBio...30E5018B |doi=10.1016/j.cub.2020.09.051 |pmc=7762822 |pmid=33065008 |last16=Cahsan |first16=Binia De |last17=Larson |first17=Greger |last18=O'Brien |first18=Stephen J. |last19=Eizirik |first19=Eduardo |last20=Johnson |first20=Warren E. |last21=Koepfli |first21=Klaus-Peter |last22=Wilting |first22=Andreas |last23=Fickel |first23=Jörns |last24=Dalén |first24=Love |last25=Lorenzen |first25=Eline D. |last26=Marques-Bonet |first26=Tomas |last27=Hansen |first27=Anders J. |last28=Zhang |first28=Guojie |last29=Bhak |first29=Jong |last30=Yamaguchi |first30=Nobuyuki |last31=Gilbert |first31=M. Thomas P.}}</ref>
[[File:Homotherium killing.png|thumb|Illustration of ''Homotherium'' delivering a killing bite to an equine, along with a diagram of the skull and neck from above, showing muscles involved in positioning head. By Mauricio Antón]]
Isotope analysis of ''Homotherium'' and other animals from the Pliocene of Hadar, Ethiopia, dating to around 3.45–2.95 million years ago, suggests that its prey at this locality were large, on average around {{Convert|200-300|kg}} and primarily consumed [[C3 plants|{{C3}} plants]]. Prey animals primarily consisted of (in descending order of importance) antelopes belonging the genus ''[[Tragelaphus]]'', the swine ''[[Nyanzachoerus]]'', the bovine ''[[Ugandax]]'', the three-toed [[hipparionine]] equine ''[[Eurygnathohippus]],'' and the antelope ''[[Damalborea]]. Homotherium'' was overlapping in diet though distinct in niche from that of the contemporary hyena ''[[Crocuta venustula]].''<ref>{{Cite journal |last=Robinson |first=Joshua R. |last2=Lazagabaster |first2=Ignacio A. |last3=Rowan |first3=John |last4=Lewis |first4=Margaret E. |last5=Werdelin |first5=Lars |last6=Campisano |first6=Christopher J. |last7=Reed |first7=Kaye E. |date=May 2025 |title=Palaeoecology of the Pliocene large carnivore guild at Hadar, Lower Awash Valley, Ethiopia |url=https://linkinghub.elsevier.com/retrieve/pii/S0047248425000065 |journal=Journal of Human Evolution |language=en |volume=202 |pages=103653 |doi=10.1016/j.jhevol.2025.103653}}</ref>

Isotopic analysis of ''H. latidens'' from the Venta Micena locality in southeast Spain dating to the Early Pleistocene, around 1.6 million years ago, suggests that at this locality ''H. latidens'' was the [[apex predator]] and hunted large prey in open habitats, with the equine ''[[Equus altidens]]'' and [[bison]] likely forming a substantial portion of its diet. Juveniles of the mammoth ''[[Mammuthus meridionalis]]'' may also have formed a significant proportion (up to 10%) of their diet. It may have also occasionally taken other prey, such as juveniles of the large hippo ''[[Hippopotamus antiquus]]''.<ref>{{Cite journal |last1=Palmqvist |first1=Paul |last2=Pérez-Claros |first2=Juan A. |last3=Janis |first3=Christine M. |last4=Gröcke |first4=Darren R. |date=August 2008 |title=Tracing the ecophysiology of ungulates and predator–prey relationships in an early Pleistocene large mammal community |url=http://www.rhinoresourcecenter.com/pdf_files/135/1358967915.pdf |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=266 |issue=1–2 |pages=95–111 |doi=10.1016/j.palaeo.2008.03.015|bibcode=2008PPP...266...95P }}</ref><ref name=":5" /> At Venta Micena, ''Homotherium'' [[niche partitioned]] with the [[Smilodontini|smilodontin]] sabertooth ''[[Megantereon]]'' (a close relative of ''Smilodon'') and the "European jaguar" ''[[Panthera gombaszoegensis]],'' which hunted somewhat smaller prey in forested habitats.<ref name=":5">{{Cite journal |last1=Palmqvist |first1=P. |last2=Perez-Claros |first2=J. A. |last3=Janis |first3=C. M. |last4=Figueirido |first4=B. |last5=Torregrosa |first5=V. |last6=Grocke |first6=D. R. |date=November 2008 |title=Biogeochemical and Ecomorphological Inferences On Prey Selection and Resource Partitioning Among Mammalian Carnivores In An Early Pleistocene Community |url=https://pubs.geoscienceworld.org/palaios/article/23/11/724-737/145947 |journal=[[PALAIOS]] |language=en |volume=23 |issue=11 |pages=724–737 |bibcode=2008Palai..23..724P |doi=10.2110/palo.2007.p07-073r |issn=0883-1351}}</ref> In Early Pleistocene Europe, the giant hyena ''[[Pachycrocuta brevirostris]]'' is likely to have presented a significant threat capable of stealing ''H. latidens'' kills.<ref>{{Cite journal |last1=Palmqvist |first1=Paul |last2=Martínez-Navarro |first2=Bienvenido |last3=Pérez-Claros |first3=Juan A. |last4=Torregrosa |first4=Vanessa |last5=Figueirido |first5=Borja |last6=Jiménez-Arenas |first6=Juan Manuel |last7=Patrocinio Espigares |first7=M. |last8=Ros-Montoya |first8=Sergio |last9=De Renzi |first9=Miquel |date=October 2011 |title=The giant hyena Pachycrocuta brevirostris: Modelling the bone-cracking behavior of an extinct carnivore |url=https://linkinghub.elsevier.com/retrieve/pii/S1040618211000115 |journal=Quaternary International |language=en |volume=243 |issue=1 |pages=61–79 |doi=10.1016/j.quaint.2010.12.035|bibcode=2011QuInt.243...61P |hdl=10630/33571 |hdl-access=free }}</ref>

Isotope analysis of specimens from Punta Lucero in northern Spain, dating to the early Middle Pleistocene (600-400,000 years ago), suggests that ''H. latidens'' at this locality exclusively consumed large (from {{Convert|45|kg|lb}} to over {{Convert|1000|kg|lb}}) prey, likely including [[aurochs]], bison, [[red deer]], and/or the giant deer ''[[Praemegaceros]],'' and heavily overlapped in diet with the coexisting European jaguar ''Panthera gombaszoegensis''.<ref>{{Cite journal |last1=Domingo |first1=Laura |last2=Rodríguez-Gómez |first2=Guillermo |last3=Libano |first3=Iñaki |last4=Gómez-Olivencia |first4=Asier |date=August 2017 |title=New insights into the Middle Pleistocene paleoecology and paleoenvironment of the Northern Iberian Peninsula (Punta Lucero Quarry site, Biscay): A combined approach using mammalian stable isotope analysis and trophic resource availability modeling |url=https://linkinghub.elsevier.com/retrieve/pii/S0277379117301099 |journal=[[Quaternary Science Reviews]] |volume=169 |pages=243–262 |bibcode=2017QSRv..169..243D |doi=10.1016/j.quascirev.2017.06.008 |via=Elsevier Science Direct}}</ref>

In the late Early Pleistocene-early Pleistocene of Java<ref name=":7" /> and Early-Middle Pleistocene of China,<ref name=":8" /> ''Homotherium'' lived alongside the extant [[tiger]], who may have competed with ''Homotherium''.<ref name=":7" />

At the Friesenhahn Cave site in Texas, which dates to the [[Late Pleistocene]] (likely around 20-17,000 years ago, during the [[Last Glacial Maximum]]<ref name="desantis etal 2021" />), the remains of almost 400 juvenile (on average around 2 years old<ref name="desantis etal 2021" />) [[Columbian mammoth]]s were discovered along with numerous ''Homotherium serum'' skeletons of all ages, from elderly specimens to cubs.<ref>{{Cite thesis |last=Metcalfe |first=Jessica |title=Late Pleistocene climate and proboscidean paleoecology in North America: Insights from stable isotope compositions of skeletal remains |date=2011 |degree=PhD |publisher=[[University of Western Ontario]] |url=https://ir.lib.uwo.ca/etd/194/}}</ref> The sloped back and powerful lumbar section of ''Homotherium''{{'}}s vertebrae suggest that these animals could have been capable of pulling formidable loads; furthermore, broken upper canines - a common injury in fossils of other machairodonts such as ''Machairodus'' and ''Smilodon'' that would have resulted from struggling with their prey - is not seen in ''Homotherium'', perhaps because their social groups would completely restrain prey items before any of the cats attempted to kill the target with their saber teeth, or because the canines were less frail due to being covered. Moreover, the bones of the young mammoths found in Friesenhahn Cave show distinctive marks matching the incisors of ''Homotherium'', indicating that they could efficiently process most of the meat on a carcass and that the mammoths had been deposited in the caves by the cats themselves and not by scavengers. Examination of the bones also indicates that the carcasses of these juvenile mammoths were dismembered after being killed by the cats before being dragged away, suggesting that ''Homotherium'' would disarticulate their kill to transport it to a safe area such as a hidden lair or den and prevent competitors such as [[Dire wolf|dire wolves]] and [[American lion]]s from usurping the carcass,<ref>{{harvnb|Antón|2013|pp=227–228}}</ref> with the meatiest parts of the juvenile mammoths like limbs being preferentially transported to the cave.<ref name="desantis etal 2021" /> Isotopic analysis of ''H. serum'' dental remains at Friesenhahn Cave have confirmed that at this locality it predominantly fed on mammoths along with other [[C4 carbon fixation|C<sub>4</sub>]] [[Grazing (behaviour)|grazers]], like bison and horses in open habitats, as well as possibly C<sub>4</sub> [[Browsing (herbivory)|browsers]] like the camel ''[[Camelops]]''.<ref name="desantis etal 2021">{{Cite journal |last1=DeSantis |first1=Larisa R. G. |last2=Feranec |first2=Robert S. |last3=Antón |first3=Mauricio |last4=Lundelius |first4=Ernest L. |date=21 June 2021 |title=Dietary ecology of the scimitar-toothed cat Homotherium serum |journal=[[Current Biology]] |volume=31 |issue=12 |pages=2674–2681.e3 |bibcode=2021CBio...31E2674D |doi=10.1016/j.cub.2021.03.061 |pmid=33862006 |doi-access=free}}</ref>

Isotopic analysis of ''H. serum'' specimens from Eastern [[Beringia]] (now Alaska and Yukon) suggests that in this region the species was not a specialised mammoth predator and consumed a variety of large prey, likely including bison, [[muskox]], horse and [[reindeer]], as well as probably [[woolly mammoth]]s.<ref>{{Cite journal |last=Bocherens |first=Hervé |date=June 2015  |title=Isotopic tracking of large carnivore palaeoecology in the mammoth steppe |url=https://linkinghub.elsevier.com/retrieve/pii/S0277379115001250 |journal=[[Quaternary Science Reviews]] |language=en |volume=117 |pages=42–71 |doi=10.1016/j.quascirev.2015.03.018|bibcode=2015QSRv..117...42B }}</ref>