Editing Cheetah (section)

===Internal anatomy===
{{multiple image |align=right |direction=vertical  |image1=Gepardjagt1 (Acinonyx jubatus).jpg |caption1=The lightly built, streamlined, agile body of the cheetah makes it an efficient sprinter |alt1=A sprinting cheetah  |image2=Acinonyx jubatus 47zz.jpg |caption2=The blunt claws and the sharp, curved [[dewclaw]] |alt2=Forepaws of a cheetah featuring blunt claws and the sharp, curved dewclaw}}
Sharply contrasting with the other big cats in its morphology, the cheetah shows several specialized adaptations for prolonged chases to catch prey at some of the fastest speeds reached by land animals.<ref name="claw">{{cite journal |last1=Russell |first1=A. P. |last2=Bryant |first2=H. N.|name-list-style=amp |title=Claw retraction and protraction in the Carnivora: the cheetah (''Acinonyx jubatus'') as an atypical felid |journal=Journal of Zoology |year=2001 |volume=254 |issue=1 |pages=67–76 |doi=10.1017/S0952836901000565}}</ref> Its light, streamlined body makes it well-suited to short, explosive bursts of speed, rapid acceleration, and an ability to execute extreme changes in direction while moving at high speed.<ref name=cheathsr>{{cite journal |last1=West |first1=T. G. |last2=Curtin |first2=N. A. |last3=McNutt |first3=J. W. |last4=Woledge |first4=R. C. |last5=Golabek |first5=K. A. |last6=Bennitt |first6=E. |last7=Bartlam-Brooks |first7=H. L. A. |last8=Dewhirst |first8=O. P. |last9=Lorenc |first9=M. |last10=Lowe |first10=J. C. |last11=Wilshin |first11=S. D. |last12=Hubel |first12=T. Y. |last13=Wilson |first13=A. M. |name-list-style=amp |date=2018 |title=Biomechanics of predator–prey arms race in lion, zebra, cheetah and impala |url=https://rvc-repository.worktribe.com/preview/1388812/11143.pdf |journal=Nature |volume=554 |issue=7691 |pages=183–188 |bibcode=2018Natur.554..183W |doi=10.1038/nature25479 |pmid=29364874 |s2cid=4405091 |access-date=24 December 2023 |archive-date=5 March 2020 |archive-url=https://web.archive.org/web/20200305065622/https://researchonline.rvc.ac.uk/id/eprint/11143/1/11143.pdf |url-status=live}}</ref><ref>{{cite journal |title=Agility, not speed, puts cheetahs ahead |journal=Science |volume=340 |issue=6138 |page=1271 |year=2013 |doi=10.1126/science.340.6138.1271-b |bibcode=2013Sci...340R1271. |last=[[American Association for the Advancement of Science]]}}</ref><ref name="WilsonBiologyLetters">{{cite journal |last1=Wilson |first1=J. W. |author2=Mills, M. G. L. |author3=Wilson, R. P. |author4=Peters, G. |author5=Mills, M. E. J. |author6=Speakman, J. R. |author7=Durant, S. M. |author8=Bennett, N. C. |author9=Marks, N. J. |author10=Scantlebury, M. |name-list-style=amp |title=Cheetahs, ''Acinonyx jubatus'', balance turn capacity with pace when chasing prey |journal=[[Biology Letters]] |volume=9 |issue=5 |year=2013 |page=20130620 |doi=10.1098/rsbl.2013.0620 |pmid=24004493 |pmc=3971710}}</ref> The large [[nasal passage]]s, accommodated well due to the smaller size of the canine teeth, ensure fast flow of sufficient air, and the enlarged heart and lungs allow the enrichment of blood with oxygen in a short time. This allows cheetahs to rapidly regain their stamina after a chase.<ref name=mammal/> During a typical chase, their [[respiratory rate]] increases from 60 to 150 breaths per minute.<ref name="O'Brien">{{cite journal |last1=O'Brien |first1=S. J. |last2=Wildt |first2=M. B. D. |name-list-style=amp |year=1986 |title=The cheetah in genetic peril |journal=Scientific American |volume=254 |issue=5 |pages=68–76 |doi=10.1038/scientificamerican0586-84 |bibcode=1986SciAm.254e..84O}}</ref> The cheetah has a fast heart rate, averaging 126–173 beats per minute at resting without arrhythmia.<ref>{{Cite journal |last1=Button |first1=C. |last2=Meltzer |first2=D. G |last3=Mülders |first3=M. S. |name-list-style=amp |date=1981 |title=The electrocardiogram of the cheetah (''Acinonyx jubatus'') |journal=Journal of the South African Veterinary Association |volume=52 |issue=3 |pages=233–235 |pmid=7310794 |url=https://journals.co.za/doi/pdf/10.10520/AJA00382809_3117}}</ref><ref>{{Cite journal |last1=Schumacher |first1=J. |last2=Snyder |first2=P. |last3=Citino |first3=S. B. |last4=Bennett |first4=R. A. |last5=Dvorak |first5=L. D. |name-list-style=amp |date=2003 |title=Radiographic and electrocardiographic evaluation of cardiac morphology and function in captive cheetahs (''Acinonyx jubatus'') |url=https://www.researchgate.net/publication/8624366 |journal=Journal of Zoo and Wildlife Medicine |volume=34 |issue=4 |pages=357–363 |doi=10.1638/01-008 |pmid=15077711}}</ref> Moreover, the reduced [[viscosity]] of the blood at higher temperatures (common in frequently moving muscles) could ease blood flow and increase [[oxygen transport]].<ref>{{cite journal |last1=Hedrick |first1=M. S. |last2=Kohl |first2=Z. F. |last3=Bertelsen |first3=M. |last4=Stagegaard |first4=J. |last5=Fago |first5=A. |last6=Wang |first6=T. |name-list-style=amp |title=Oxygen transport characteristics of blood from the fastest terrestrial mammal, the African cheetah (''Acinonyx jubatus'') |journal=The FASEB Journal |date=2019 |volume=33 |issue=S1 |doi=10.1096/fasebj.2019.33.1_supplement.726.2 |doi-access=free}}</ref> While running, in addition to having good traction due to their semi-retractable claws, cheetahs use their tail as a rudder-like means of steering that enables them to make sharp turns, necessary to outflank antelopes which often change direction to escape during a chase.<ref name=wcw/><ref name=mills/> The protracted claws increase grip over the ground, while rough paw pads make the sprint more convenient over tough ground. The limbs of the cheetah are longer than what is typical for other cats its size; the thigh muscles are large, and the [[tibia]] and [[fibula]] are held close together making the lower legs less likely to rotate. This reduces the risk of losing balance during runs, but compromises the cat's ability to climb trees. The highly reduced [[clavicle]] is connected through [[ligament]]s to the [[scapula]], whose pendulum-like motion increases the stride length and assists in shock absorption. The extension of the [[vertebral column]] can add as much as {{cvt|76|cm}} to the stride length.<ref name=hildebrand>{{cite journal |last1=Hildebrand |first1=M. |year=1961 |title=Further studies on locomotion of the cheetah |url=https://www.originalwisdom.com/wp-content/uploads/bsk-pdf-manager/2019/04/Hildebrand_1961_Further-Studies-on-Locomotion-of-the-Cheetah.pdf |journal=Journal of Mammalogy |volume=42 |issue=1 |pages=84–96 |doi=10.2307/1377246 |jstor=1377246 |access-date=21 December 2023 |archive-date=21 December 2023 |archive-url=https://web.archive.org/web/20231221042523/https://www.originalwisdom.com/wp-content/uploads/bsk-pdf-manager/2019/04/Hildebrand_1961_Further-Studies-on-Locomotion-of-the-Cheetah.pdf |url-status=live}}</ref><ref name=bertram>{{cite journal |last1=Bertram |first1=J. E. A. |last2=Gutmann |first2=A. |title=Motions of the running horse and cheetah revisited: fundamental mechanics of the transverse and rotary gallop |journal=Journal of the Royal Society Interface |year=2009 |volume=6 |issue=35 |pages=549–559 |doi=10.1098/rsif.2008.0328 |pmid=18854295 |pmc=2696142 |name-list-style=amp}}</ref>

Muscle tissue has been analyzed in the cheetah and it has been found that there are little differences in [[type II muscle fiber]] concentration, anaerobic [[lactate dehydrogenase]] enzyme activity, and [[glycogen]] concentration between sexes.<ref name=":0">{{Cite journal |last1=Kohn |first1=T. A. |last2=Knobel |first2=S. |last3=Donaldson |first3=B. |last4=van Boom |first4=K. M. |last5=Blackhurst |first5=D. M. |last6=Peart |first6=J. M. |last7=Jensen |first7=J. |last8=Tordiffe |first8=A. S. W. |date=2024 |title=Does sex matter in the cheetah? Insights into the skeletal muscle of the fastest land animal |journal=Journal of Experimental Biology |volume=227 |issue=15 |pages=jeb247284 |doi=10.1242/jeb.247284 |doi-access=free |pmid=39023116 |pmc=11418166 |bibcode=2024JExpB.227B7284K}}</ref>

{{multiple image |align=left |direction=vertical  |image1=Description iconographique comparée du squelette et du système dentaire des mammifères récents et fossiles (Acinonyx jubatus skull).jpg |caption1=Cheetah skull. |alt1=Skull of a cheetah  |image2=Description iconographique comparée du squelette et du système dentaire des mammifères récents et fossiles (Acinonyx jubatus).jpg |caption2=Cheetah skeleton. Note the deep chest and long limbs. |alt2=Skeleton of a cheetah}}

The cheetah resembles the smaller cats in [[Skull|cranial]] features, and in having a long and flexible spine, as opposed to the stiff and short one in other large felids.<ref name=mammal/> The roughly triangular skull has light, narrow bones and the [[sagittal crest]] is poorly developed, possibly to reduce weight and enhance speed. The mouth can not be opened as widely as in other cats given the shorter length of muscles between the jaw and the skull.<ref name=wcw/><ref name="hilde"/> A study suggested that the limited retraction of the cheetah's claws may result from the earlier truncation of the development of the middle [[phalanx bone]] in cheetahs.<ref name=claw/>

The cheetah has a total of 30 teeth; the [[dental formula]] is {{DentalFormula|upper=3.1.3.1|lower=3.1.2.1}}. The small, flat [[Canine tooth|canines]] are used to bite the throat and suffocate the prey. A study gave the [[bite force quotient]] (BFQ) of the cheetah as 119, close to that for the lion (112), suggesting that adaptations for a lighter skull may not have reduced the power of the cheetah's bite.<ref name=mammal/><ref name=marker7/> Unlike other cats, the cheetah's canines have no gap or diastema behind them when the jaws close, as the top and bottom cheek teeth show extensive overlap.<ref name="bcw3" /> Cheetahs have relatively elongated, blade-like shape [[carnassial]] teeth, with reduced lingual cusps; this may have been an adaptation to consume quickly the flesh of a prey before more heavy-built predators from other species arrive to take it from them.<ref>{{Cite book |last=Antón |first=M. |url=https://archive.org/details/Sabertooth/page/n207/mode/1up |title=Sabertooth |date=2013 |publisher=Indiana University Press |pages=185}}</ref> The slightly curved claws, shorter and straighter than those of other cats, lack a protective sheath and are partly retractable.<ref name=wcw/><ref name=nowak/> The claws are blunt due to lack of protection,<ref name=hunterwcw/> but the large and strongly curved [[dewclaw]] is remarkably sharp.<ref name=dewclaw>{{cite journal |last1=Londei |first1=T. |year=2000 |title=The cheetah (''Acinonyx jubatus'') dewclaw: specialization overlooked |journal=Journal of Zoology |volume=251 |issue=4 |pages=535–547 |doi=10.1111/j.1469-7998.2000.tb00809.x |doi-access=free}}</ref> Cheetahs have a high concentration of [[nerve cell]]s arranged in a band in the centre of the eyes, a visual streak, the most efficient among felids. This significantly sharpens the vision and enables the cheetah to swiftly locate prey against the horizon.<ref name=bcw3/><ref>{{cite journal |last1=Ahnelt |first1=P. K. |last2=Schubert |first2=C. |last3=Kuebber-Heiss |first3=A. |last4=Anger |first4=E. M. |name-list-style=amp |title=Adaptive design in felid retinal cone topographies |journal=Investigative Ophthalmology & Visual Science |date=2005 |volume=46 |issue=13 |page=4540 |url=https://www.researchgate.net/publication/264402644 |access-date=21 April 2020 |archive-date=5 May 2024 |archive-url=https://web.archive.org/web/20240505152107/https://www.researchgate.net/publication/264402644_Adaptive_Design_in_Felid_Retinal_Cone_Topographies |url-status=live}}</ref> The cheetah is unable to roar due to the presence of a sharp-edged vocal fold within the [[larynx]].<ref name=mammal/><ref name=hast>{{cite journal |last1=Hast |first1=M. H. |title=The larynx of roaring and non-roaring cats |journal=[[Journal of Anatomy]] |year=1989 |volume=163 |pages=117–121 |pmid=2606766 |pmc=1256521}}</ref>

In stressful situations, the cheetah has a lower [[cortisol]] level than the leopard, indicating better stress response; it also has lower [[immunoglobulin G]] and [[Serum amyloid A]] levels but a higher [[lysozyme]] level and a higher bacterial killing capacity than the leopard, indicating a poorer [[adaptive immune system|adaptive]] and induced [[innate immune system]]s but a better constitutive innate immune system; its constitutive innate immune system compensates for its low variation of [[major histocompatibility complex]] and poorer immune adaptability.<ref>{{Cite journal |last1=Heinrich |first1=S. K. |last2=Hofer |first2=H. |last3=Courtiol |first3=A. |last4=Melzheimer |first4=J. |last5=Dehnhard |first5=M. |last6=Czirják |first6=G. Á. |last7=Wachter |first7=B. |date=2017 |title=Cheetahs have a stronger constitutive innate immunity than leopards |journal=Scientific Reports |volume=7 |issue=1 |pages=44837 |doi=10.1038/srep44837 |pmc=5363065 |pmid=28333126 |bibcode=2017NatSR...744837H}}</ref>