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==Paleobiologia==
===Funzione dell'artiglio===
ThereLa isfunzione currentlydell'artiglio disagreementfalciforme aboutsul thesecondo functiondito ofdel thepiede enlargedè "sickleuna claw" on thefonte seconddi toedibattito. WhenQuando John Ostrom describedlo itdescrisse forper ''Deinonychus'' innel 1969, heipotizzò interpretedche thel'artiglio clawfosse asusato aper blade-likesventrare slashingle weaponprede, muchcome likei thedenti caninescanini of somedelle [[Homotherium|saber-toothedtigri cats]],dai useddenti witha powerfulsciabola]]. kicksDawn toAdams cutsuggerì intonel prey. Adams (1987) suggestedche thatl'artiglio thefosse talonusato wasper usedeviscerare toi disembowel largedinosauri [[ceratopsianCeratopsidae|ceratopsidi]] dinosaurs.<ref name=Adams1987>Adams, Dawn (1987) "The bigger they are, the harder they fall: Implications of ischial curvature in ceratopsian dinosaurs" pg 1–6 in Currie, Philip J. and Koster, E. (eds) Fourth symposium on mesozoic terrestrial ecosystems. Tyrrell Museum, Drumheller, Canada</ref> TheQuesta interpretationinterpretazione offu the sickle claw asapplicata a killingtutti weaponi applieddromaeosauridi. toNel all dromaeosaurids.2005 Howeverperò, Manningfu ''etsuggerito al.'che l'artiglio arguedfosse thatinvece theusato clawprincipalmente insteadper served as a hookl'arrampicamento, reconstructingma theche keratinouspotesse sheathanche withessere anusato ellipticalper crosspugnalare section, instead of the previouslyle inferredprede invertedpiuttosto teardropche shapesventrarle.<ref name="manningetal2005">{{cite journal | author = Manning, P.L., Payne, D., Pennicott, J., Barrett, P.M., and Ennos, R.A. | year = 2005 | title = Dinosaur killer claws or climbing crampons? | url = http://www.journals.royalsoc.ac.uk/openurl.asp?genre=article&eissn=1744-957X&volume=2&issue=1&spage=110 | journal = Biology Letters | volume = 2 | pages = 110–112 | doi = 10.1098/rsbl.2005.0395 | pmid = 17148340 | issue = 1 | pmc = 1617199 }}</ref> In Manning's interpretation, the second toe claw would be used as a climbing aid when subduing bigger prey and also as stabbing weapon.
OstromNel compareddescrivere ''Deinonychus'' , toOstrom thelo paragonò con lo [[ ostrichStruthio camelus|struzzo]] ande il [[ cassowaryCasuarius casuarius|casuario]] ., Henotando notedche thatentrambi thequesti birduccelli speciessono canforniti inflictdi seriousartigli injuryletali withsul the largesecondo claw on the second toedito.<ref name="ostrom1969"/> TheIl cassowarycasuario hasin clawsparticolare upè tofornito d'un artiglio lungo {{convert|125 | mm |in}} long.<ref name=Davies2002>Davies, S.J.J.F. (2002) "Ratites and Tinamous" Oxford University Press. New York, USA</ref> Ostrom citedcitò Gilliard (1958) innel sayingdescrivere thatcome theyil cancasuario severè ancapace armdi ormenomare disembowele asventrare manun umano.<ref name=Gilliard1958>Gilliard, E. T. (1958) "Living birds of the world" Doubleday, garden City, NY. USA. 400p.</ref> KofronDegli studi condotti nel (1999 ande nel 2003 ) studiedperò mostrarono che fra 241 documentedattacchi cassowaryda attacksparte anddi foundcasuari thatregistrati, oneperirono humansolo anduna twopersona dogse haddue beencani. killed,Non butci nofurono evidenceprove thatche cassowariesle canvittime disembowelfossero orsmembrate dismembero other animalssventrate.<ref name=Kofron1999>{{cite journal | last1 = Kofron | first1 = Christopher P. | doi = 10.1111/j.1469-7998.1999.tb01206.x | title = Attacks to humans and domestic animals by the southern cassowary (Casuarius casuarius johnsonii) in Queensland, Australia | journal = Journal of Zoology | year = 1999 | volume = 249 | pages=375–381 | issue = 4 }}</ref><ref name=Kofron2003>{{cite journal | last1 = Kofron | first1 = Christopher P. | year = 2003 | title = Case histories of attacks by the southern cassowary in Queensland | url = | journal = Memoirs of the Queensland Museum | volume = 49 | issue = 1| pages = 335–338 }}</ref> CassowariesI usecasuari theirinfatti clawsusano toi defendloro themselves,artigli toper attack threatening animalsdifendersi, andper inattaccare agonisticminacce, displayse suchper asminacciare the Bowed Threati Displayrivali.<ref name="Davies2002"/> TheLa [[ Cariamidae|seriema]] alsoè hasun analtro enlargeduccello seconddotato toed'un claw,artiglio andingrandito usessul itsecondo todito; lo usa tearper apartsmembrare smallpiccole preyprede itemsprima fordi swallowingconsumarle.<ref name=Redford&Peters1986>{{cite journal | last1 = Redford | first1 = Kent H. | last2 = Peters | first2 = Gustav | year = 1986| title = Notes on the biology and song of the red-legged seriema (cariama cristata) | journal = Journal of Field Ornithology | volume = 57 | issue = 4| pages = 261–269 | jstor=4513154}}</ref> ▼[[File:Deinonychus (Raptor Prey Restraint).jpg|thumb|left|Life restoration of a ''[[Deinonychus]]'' preying on a ''[[Zephyrosaurus]]'' using the sickle claw for prey restraint.]]
▲Ostrom compared ''Deinonychus'' to the [[ostrich]] and [[cassowary]]. He noted that the bird species can inflict serious injury with the large claw on the second toe.<ref name="ostrom1969"/> The cassowary has claws up to {{convert|125|mm|in}} long.<ref name=Davies2002>Davies, S.J.J.F. (2002) "Ratites and Tinamous" Oxford University Press. New York, USA</ref> Ostrom cited Gilliard (1958) in saying that they can sever an arm or disembowel a man.<ref name=Gilliard1958>Gilliard, E. T. (1958) "Living birds of the world" Doubleday, garden City, NY. USA. 400p.</ref> Kofron (1999 and 2003) studied 241 documented cassowary attacks and found that one human and two dogs had been killed, but no evidence that cassowaries can disembowel or dismember other animals.<ref name=Kofron1999>{{cite journal | last1 = Kofron | first1 = Christopher P. | doi = 10.1111/j.1469-7998.1999.tb01206.x | title = Attacks to humans and domestic animals by the southern cassowary (Casuarius casuarius johnsonii) in Queensland, Australia | journal = Journal of Zoology | year = 1999 | volume = 249 | pages=375–381 | issue = 4 }}</ref><ref name=Kofron2003>{{cite journal | last1 = Kofron | first1 = Christopher P. | year = 2003 | title = Case histories of attacks by the southern cassowary in Queensland | url = | journal = Memoirs of the Queensland Museum | volume = 49 | issue = 1| pages = 335–338 }}</ref> Cassowaries use their claws to defend themselves, to attack threatening animals, and in agonistic displays such as the Bowed Threat Display.<ref name="Davies2002"/> The [[seriema]] also has an enlarged second toe claw, and uses it to tear apart small prey items for swallowing.<ref name=Redford&Peters1986>{{cite journal | last1 = Redford | first1 = Kent H. | last2 = Peters | first2 = Gustav | year = 1986| title = Notes on the biology and song of the red-legged seriema (cariama cristata) | journal = Journal of Field Ornithology | volume = 57 | issue = 4| pages = 261–269 | jstor=4513154}}</ref>
Phillip Manning and colleagues (2009) attempted to test the function of the sickle claw and similarly shaped claws on the forelimbs. They analyzed the bio-mechanics of how stresses and strains would be distributed along the claws and into the limbs, using X-ray imaging to create a three-dimensional contour map of a forelimb claw from ''[[Velociraptor]]''. For comparison, they analyzed the construction of a claw from a modern predatory bird, the [[eagle owl]]. They found that, based on the way that stress was conducted along the claw, they were ideal for climbing. The scientists found that the sharpened tip of the claw was a puncturing and gripping instrument, while the curved and expanded claw base helped transfer stress loads evenly.<ref name=manningetal2009>{{cite journal | doi = 10.1002/ar.20986 | last1 = Manning | first1 = P.L. | last2 = Margetts | first2 = L. | last3 = Johnson | first3 = M.R. | last4 = Withers | first4 = P.J. | last5 = Sellers | first5 = W.I. | last6 = Falkingham | first6 = P.L. | last7 = Mummery | first7 = P.M. | last8 = Barrett | first8 = P.M. | last9 = Raymont | first9 = D.R. | year = 2009 | title = Biomechanics of dromaeosaurid dinosaur claws: Application of X-ray microtomography, nanoindentation, and finite element analysis | url = | journal = The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology | volume = 292 | issue = 9| pages = 1397–1405 |display-authors=etal}}</ref>
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