Editing Chameleon (section)

===Feeding===
All chameleons are primarily [[insectivore]]s that feed by [[projectile use by living systems|ballistically projecting]] their long [[tongue]]s from their mouths to capture prey located some distance away.<ref name="Higham and Anderson 2014">{{Citation |last1= Higham |first1= T. E. |last2= Anderson |first2= C. V. |contribution= Function and adaptation of chameleons |editor-last= Tolley |editor-first= K. A. |editor-last2= Herrel |editor-first2= A. |title= The Biology of Chameleons |pages= 63–83 |publisher= University of California Press |place=Berkeley, CA |year= 2014 |isbn=9780520276055}}</ref> While the chameleons' tongues are typically thought to be one and a half to two times the length of their bodies (their length excluding the tail), smaller chameleons (both smaller species and smaller individuals of the same species) have recently been found to have proportionately larger tongue apparatuses than their larger counterparts.<ref name="Anderson et al. 2012">{{cite journal |doi=10.1002/jmor.20053 |pmid= 22730103 |title= Scaling of the ballistic tongue apparatus in chameleons |author1= Anderson, C. V.|author2= Sheridan, T. |author3= Deban, S. M. |journal=Journal of Morphology |year=2012 |volume=273 |issue= 11 |pages=1214–1226 |s2cid= 21033176 }}</ref> Thus, smaller chameleons are able to project their tongues greater distances than the larger chameleons that are the subject of most studies and tongue length estimates, and can project their tongues more than twice their body length.<ref>Anderson, Christopher V. (2009) [http://www.chamaeleonidae.com/Movies/Pages/Rhampholeon_spinosus.html ''Rhampholeon spinosus'' feeding video]. chamaeleonidae.com</ref>

The tongue apparatus consists of highly modified [[Hyoid|hyoid bones]], [[Muscles of tongue|tongue muscles]], and [[Collagen|collagenous elements]].<ref name="Herrel et al. 2001">{{cite journal |title= Morphology and histochemistry of the hyolingual apparatus in chameleons |author= Herrel, A. |author2= Meyers, J. J.|author3= Nishikawa, K. C. |author4= De Vree, F. |journal=Journal of Morphology |year=2001 |volume=249 |issue= 2 |pages=154–170 |doi=10.1002/jmor.1047|pmid= 11466743 |s2cid= 3246256 }}</ref><ref name="de Groot & van Leeuwen 2004">{{cite journal |title= Evidence for an elastic projection mechanism in the chameleon tongue |author1=de Groot, J. H. |author2=van Leeuwen, J. L. |journal=Proceedings of the Royal Society of London B |year=2004 |volume=271 |issue= 1540 |pages=761–770 |doi=10.1098/rspb.2003.2637 |pmid=15209111 |pmc=1691657 }}</ref><ref name="Anderson et al. 2012"/><ref name="Anderson and Higham 2014">{{Citation |last1= Anderson |first1= C. V. |last2= Higham |first2= T. E. |contribution= Chameleon anatomy |editor-last= Tolley |editor-first= K. A. |editor-last2= Herrel |editor-first2= A. |title= The Biology of Chameleons |pages= 7–55 |publisher= University of California Press |place=Berkeley, CA |year= 2014 |isbn=9780520276055}}</ref> The hyoid bone has an elongated, parallel-sided projection, called the entoglossal process, over which a tubular muscle, the accelerator muscle, sits.<ref name="Anderson et al. 2012"/><ref name="Anderson and Higham 2014"/><ref name="Herrel et al. 2001"/><ref name="de Groot & van Leeuwen 2004"/> The accelerator muscle contracts around the entoglossal process and is responsible for creating the work to power tongue projection, both directly and through the loading of collagenous elements located between the entoglossal process and the accelerator muscle.<ref name="Higham and Anderson 2014"/><ref name="Anderson et al. 2012"/><ref name="Herrel et al. 2001"/><ref name="de Groot & van Leeuwen 2004"/> The tongue retractor muscle, the hyoglossus, connects the hyoid and accelerator muscle, and is responsible for drawing the tongue back into the mouth following tongue projection.<ref name="Higham and Anderson 2014"/><ref name="Anderson et al. 2012"/><ref name="Anderson and Higham 2014"/><ref name="Herrel et al. 2001"/>

Tongue projection occurs at extremely high performance, reaching the prey in as little as 0.07 seconds,<ref name="Herrel et al. 2001"/><ref name="de Groot & van Leeuwen 2004"/><ref name="Anderson & Deban 2010">{{cite journal |doi=10.1073/pnas.0910778107 |title= Ballistic tongue projection in chameleons maintains high performance at low temperature |author1=Anderson, C. V. |author2=Deban, S. M. |journal=Proceedings of the National Academy of Sciences of the United States of America |year=2010 |volume=107 |issue= 12 |pages=5495–5499|bibcode= 2010PNAS..107.5495A |pmid=20212130 |pmc=2851764|doi-access= free }}</ref> having been launched at accelerations exceeding 41 [[G force|''g'']].<ref name="Anderson & Deban 2010"/> The [[Power (physics)|power]] with which the tongue is launched, known to exceed 3000 W kg<sup>−1</sup>, exceeds that which muscle is able to produce, indicating the presence of an elastic power amplifier to power tongue projection.<ref name="de Groot & van Leeuwen 2004"/> The recoil of elastic elements in the tongue apparatus is thus responsible for large percentages of the overall tongue projection performance.

One consequence of the incorporation of an elastic recoil mechanism to the tongue projection mechanism is relative thermal insensitivity of tongue projection relative to tongue retraction, which is powered by muscle contraction alone, and is heavily thermally sensitive.<ref name="Anderson & Deban 2010"/><ref name="Anderson & Deban 2012">{{cite journal |doi=10.1242/jeb.078881 |title= Thermal effects on motor control and ''in vitro'' muscle dynamics of the ballistic tongue apparatus in chameleons |author1=Anderson, C. V. |author2=Deban, S. M. |journal=Journal of Experimental Biology |year=2012 |volume=215 |issue= 24 |pages=4345–4357 |pmid=23125336|doi-access=free }}</ref> While other [[Ectotherm|ectothermic animals]] become sluggish as their body temperatures decline, due to a reduction in the contractile velocity of their muscles, chameleons are able to project their tongues at high performance even at low body temperatures.<ref name="Anderson & Deban 2010"/><ref name="Anderson & Deban 2012"/> The thermal sensitivity of tongue retraction in chameleons, however, is not a problem, as chameleons have a very effective mechanism of holding onto their prey once the tongue has come into contact with it, including surface phenomena, such as wet adhesion and interlocking, and suction.<ref name="Herrel et al. 2000">{{cite journal |title=The mechanics of prey prehension in chameleons |author=Herrel, A. |author2=Meyers, J. J. |author3=Aerts, P. |author4=Nishikawa, K. C. |journal=Journal of Experimental Biology |year=2000 |volume=203 |issue=Pt 21 |pages=3255–3263 |doi=10.1242/jeb.203.21.3255 |url=http://www2.nau.edu/froggy-p/pdfs/Herrel%20et%20al.%202000.pdf |pmid=11023845 |access-date=2014-11-16 |archive-date=2010-06-20 |archive-url=https://web.archive.org/web/20100620023301/http://www2.nau.edu/froggy-p/pdfs/Herrel%20et%20al.%202000.pdf |url-status=dead }}</ref> The thermal insensitivity of tongue projection thus enables chameleons to feed effectively on cold mornings prior to being able to behaviorally elevate their body temperatures through [[thermoregulation]], when other [[sympatric]] lizards species are still inactive, likely temporarily expanding their thermal [[Ecological niche|niche]] as a result.<ref name="Anderson & Deban 2010"/>

<gallery mode="packed" heights="140px" caption="Use of tongue in feeding">
File:Chameleon gab fbi.png|Tongue structure, with cup-like end
File:Chameleon-Stage 04.jpg|Tongue begins strike
File:Chameleon-Stage 03.jpg|Capturing prey
File: Chameleon-Stage 01.jpg|Bringing prey to the mouth
</gallery>