Editing Snake (section)

=== Skeleton ===
{{main|Snake skeleton}}
[[File:Reticulated python (Python reticulatus) skull 1 (cropped).jpg|thumb|[[Reticulated python]] skull, showing jaw movements when swallowing]]
The skull of a snake differs from a lizards in several ways. Snakes have more flexible jaws, that is, instead of a juncture at the upper and lower jaw, the snake's jaws are connected by a bone hinge that is called the [[quadrate bone]]. Between the two halves of the lower jaw at the chin there is an elastic ligament that allows for a separation. This allows the snake to swallow food larger in proportion to their size and go longer without it, since snakes ingest relatively more in one feeding.{{sfn|Campbell|Shaw|1974|p=11}} Because the sides of the lower jaw can move independently of one another, a snake resting its jaw on a surface has stereo [[Hearing|auditory perception]], used for detecting the position of prey. The jaw–quadrate–[[stapes]] pathway is capable of detecting vibrations on the [[angstrom]] scale, despite the absence of an outer ear and the lack of an [[impedance matching]] mechanism—provided by the [[ossicles]] in other vertebrates.<ref>{{cite journal |vauthors=Friedel P, Young BA, van Hemmen JL |title=Auditory localization of ground-borne vibrations in snakes |journal=[[Physical Review Letters]] |volume=100 |issue=4 |pages=048701 |date=February 2008 |pmid=18352341 |doi=10.1103/physrevlett.100.048701 |bibcode=2008PhRvL.100d8701F}}</ref><ref>{{cite web |url=http://www.physorg.com/news122123444.html |title=Desert Snake Hears Mouse Footsteps with its Jaw |date=February 13, 2008 |first=Lisa |last=Zyga |name-list-style=vanc |publisher=[[Phys.org]] |url-status=live |archive-url=https://web.archive.org/web/20111010152337/http://www.physorg.com/news122123444.html |archive-date=October 10, 2011}}</ref> In a snake's skull the brain is well protected. As brain tissues could be damaged through the palate, this protection is especially valuable. The solid and complete [[neurocranium]] of snakes is closed at the front.{{sfn|Campbell|Shaw|1974}}{{page needed|date=April 2024}}<ref>{{cite journal |vauthors=Hartline PH |title=Physiological basis for detection of sound and vibration in snakes |journal=The Journal of Experimental Biology |volume=54 |issue=2 |pages=349–71 |date=April 1971 |doi=10.1242/jeb.54.2.349 |pmid=5553415 |bibcode=1971JExpB..54..349H |url=http://jeb.biologists.org/cgi/reprint/54/2/349.pdf |url-status=live |archive-url=https://web.archive.org/web/20081217012157/http://jeb.biologists.org/cgi/reprint/54/2/349.pdf |archive-date=December 17, 2008}}</ref>

[[File:Snake Skeletons.jpg|thumb|The skeletons of snakes are radically different from those of most other reptiles (as compared with the [[turtle]] here, for example), consisting almost entirely of an extended ribcage.]]

The skeleton of most snakes consists solely of the skull, [[hyoid]], vertebral column, and ribs, though [[henophidia]]n snakes retain vestiges of the pelvis and rear limbs.  The hyoid is a small bone located posterior and ventral to the skull, in the 'neck' region, which serves as an attachment for the muscles of the snake's tongue, as it does in all other [[tetrapod]]s. The vertebral column consists of between 200 and 400 vertebrae, or sometimes more. The body vertebrae each have two ribs articulating with them. The tail vertebrae are comparatively few in number (often less than 20% of the total) and lack ribs. The vertebrae have projections that allow for strong muscle attachment, enabling locomotion without limbs.{{Citation needed|date=November 2024}}

Caudal [[autotomy]] (self-amputation of the tail), a feature found in some lizards, is absent in most snakes.<ref>Cogger, H 1993 Fauna of Australia. Vol. 2A Amphibia and Reptilia. Australian Biological Resources Studies, Canberra.</ref> In the rare cases where it does exist in snakes, caudal autotomy is intervertebral (meaning the separation of adjacent vertebrae), unlike that in lizards, which is intravertebral, i.e. the break happens along a predefined fracture plane present on a vertebra.<ref>{{cite journal |vauthors=Arnold EN |doi=10.1080/00222938400770131 |title=Evolutionary aspects of tail shedding in lizards and their relatives |journal=[[Journal of Natural History]] |year=1984 |volume=18 |issue=1 |pages=127–169|bibcode=1984JNatH..18..127A }}</ref><ref>{{cite journal |vauthors=Ananjeva NB, Orlov NL |year=1994 |title=Caudal autotomy in Colubrid snake ''Xenochrophis piscator'' from Vietnam |journal=Russian Journal of Herpetology |volume=1 |issue=2}}</ref>

In some snakes, most notably boas and pythons, there are vestiges of the hindlimbs in the form of a pair of [[pelvic spur]]s. These small, claw-like protrusions on each side of the cloaca are the external portion of the vestigial hindlimb skeleton, which includes the remains of an ilium and femur.{{Citation needed|date=November 2024}}

Snakes are [[polyphyodont]]s with teeth that are continuously replaced.<ref>{{cite journal |vauthors=Gaete M, Tucker AS |title=Organized emergence of multiple-generations of teeth in snakes is dysregulated by activation of Wnt/beta-catenin signalling |journal=[[PLOS ONE]] |volume=8 |issue=9 |pages=e74484 |year=2013 |pmid=24019968 |pmc=3760860 |doi=10.1371/journal.pone.0074484 |bibcode=2013PLoSO...874484G |doi-access=free}}</ref>