Editing Animal weapon (section)

==Occurrence==
[[File:Male Long-nosed Chameleon (Calumma gallus), Vohimana reserve, Madagascar.jpg|thumb|left|upright=1.25|The horn-like projections of a [[chameleon]] are used to fight other males on tree trunks.]]
Weapons are common among many genera of animals. Among [[vertebrates]], they are most often found in [[mammals]] and [[fish]], and are also known to occur in [[reptiles]], though far less commonly in that class. Many species of [[dinosaur]], an extinct clade of vertebrates, also possessed weapons. Arthropods, such as [[arachnids]] and [[crabs]], also have species that wield weapons, and they are extraordinarily widespread among [[insects]]. <ref name="Emlen2008"></ref> 

In mammals, weapons are common and take a number of diverse forms. They are most common among the [[ungulates]].<ref name="Emlen2008"></ref>  [[Antlers]], complex and unique weapons that are an extension of an animal's skull, are found among male [[deer]]s, as well as female [[reindeer]]s, ungulates who are even-toed ruminants.<ref name="Lincoln1992">{{Cite journal |last1=Lincoln |first1=G. A.|title=Biology of antlers |url=https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-7998.1992.tb07495.x |journal=Journal of Zoology |date=March 1992 |language=en |volume=226 |issue=3 |pages=517–528 |doi=10.1111/j.1469-7998.1992.tb07495.x |url-access=registration }}</ref> [[Horn (anatomy)|Horn]]s, permanent pointed projections consisting of a covering of [[keratin]] and other [[protein]]s surrounding a core of live [[bone]], are found commonly among [[bovid]]s, as well as the [[pronghorn]]s, which are [[ruminant]] [[artiodactyl]]s. [[Rhinoceros]]es are odd-toed ungulates which have horns made of [[keratin]]; both sexes use these horns in contests with other individuals of the same species.<ref name="Berger1998">{{Cite journal |last1=Berger |first1=Joel |last2=Cunningham |first2=Carol |title=Natural variation in horn size and social dominance and their importance to the conservation of black rhinoceros |url=https://www.jstor.org/stable/2387253 |journal=Conservation Biology |date=June 1998 |language=en |volume=12 |issue=3 |pages=708–711 |doi=10.1111/j.1523-1739.1998.97207.x |jstor=2387253 |url-access=subscription }}</ref> Walruses and elephants, non-ungulates, both possess elongated tusks. Apart from mammals, the only other group of land vertebrates that shows widespread adoption of weapons are the [[chameleons]], who possess horn-like structures for fighting over access to mates.<ref name="Emlen2008"></ref>

[[File:Kabutomushi-JapaneseBeetle-July2004.jpg|thumb|upright=1|The horns of a rhinoceros beetle are an example of one of the many weapons insects possess.]]

Some species of fish have weapons, though these traits are not as widespread as in mammals. [[Sawfish]] are named for their long [[Rostrum (anatomy)|rostrum]], which can be used to inflict damage on other fish.<ref name="Wueringer2009">{{Cite journal |last1=Wueringer |first1=Barbara E. |last2=Squire |first2=Lyle |last3=Collin |first3=S. P. |title=The biology of extinct and extant sawfish (Batoidea: Sclerorhynchidae and Pristidae) |url=https://link.springer.com/article/10.1007/s11160-009-9112-7 |journal=Reviews in Fish Biology and Fisheries |date=2009-03-19 |language=en |volume=19 |issue=4 |pages=445–464|doi=10.1007/s11160-009-9112-7 |bibcode=2009RFBF...19..445W |url-access=subscription }}</ref> [[Naso (fish)|Unicornfish]] may also use their strange horn-like forehead protection as a weapon, although the general use of this and many similar structures in fish are still somewhat enigmatic. <ref name="Emlen2008"></ref> Male salmon notably feature intraspecific competition for mates, and they use their elongated and toothy jaw to fight other males, both over access to females and over access to breeding sites.<ref name="Emlen2008"></ref><ref name="Fleming1994">{{Cite journal |last1=Fleming |first1=Ian A. |title=Captive breeding and the conservation of wild salmon populations |url=https://www.jstor.org/stable/2386541 |journal=Conservation Biology |date=Sep 1994 |language=en |volume=8 |issue=3 |pages=886–888|doi=10.1046/j.1523-1739.1994.08030863-13.x |jstor=2386541 |bibcode=1994ConBi...8..886F |url-access=subscription }}</ref><ref name="Quinn1999">{{Cite journal |last1=Quinn |first1=Thomas P. |title=Variation in Pacific salmon reproductive behaviour associated with species, sex and levels of competition |url=https://brill.com/view/journals/beh/136/2/article-p179_3.xml |journal=Behaviour |date=Mar 1999 |language=en |volume=136 |issue=2 |pages=179–204 |doi=10.1163/156853999501270 |url-access=subscription}}</ref> 

Weapons are very widespread among insects, having been observed in nearly every major taxonomic group.<ref name="Emlen2008"></ref> Insects possess a huge variety of weapons, often with entirely different uses and modes of action. [[Rhinoceros beetles]], like the mammal they are named for, have large horns which they famously use to fight for mates.<ref name="Karino2005">{{Cite journal |last1=Karino |first1=Kenji |last2=Niiyama |first2=Hisatsugu |last3=Chiba |first3=Mutsumi  |title=Horn length is the determining factor in the outcomes of escalated fights among male Japanese horned beetles, Allomyrina dichotoma L.(Coleoptera: Scarabaeidae) |url=https://link.springer.com/article/10.1007/s10905-005-8741-5 |journal=Journal of Insect Behavior |date=2005 |language=en |volume=18 |issue=6 |pages=805–815|doi=10.1007/s10905-005-8741-5 |bibcode=2005JIBeh..18..805K |url-access=subscription }}</ref><ref name="Buchalski2019">{{cite journal |last1=Buchalski |first1=Benjamin |last2=Gutierrez |first2=Eric |last3=Emlen |first3=Douglas |last4=Lavine |first4=Laura |last5=Swanson |first5=Brook |title=Variation in an Extreme Weapon: Horn Performance Differences across Rhinoceros Beetle (Trypoxylus dichotomus) Populations |journal=Insects |date=15 October 2019 |volume=10 |issue=10 |pages=346 |doi=10.3390/insects10100346 |pmid=31618906 |pmc=6835817 |doi-access=free }}</ref> [[Stag beetles]] have enlarged [[mandible]]s, which resemble the antlers of stags. Male stag beetles use these weapons to wrestle each other for favoured mating sites in a way that [[Convergent evolution|parallels]] the way [[Deer#Antlers|stags]] fight over females. Fights may also be over food, such as tree sap and decaying fruits. <ref>:Goyens J, Van Wassenbergh
S, Dirckx J, Aerts P. 2015 Cost of flight and the
evolution of stag beetle weaponry. J. R. Soc.
Interface 12: 20150222.
http://dx.doi.org/10.1098/rsif.2015.0222</ref> [[Harlequin beetles]] have legs that are longer than their entire body, using which they protect a suitable spot for a female to lay eggs. They also possess strong mandibles to bite other males, which can include removing their legs.<ref name="Zeh1992">{{cite journal |last1=Zeh |first1=David W. |last2=Zeh |first2=Jeanne A. |last3=Tavakilian |first3=Gerard |year=1992 |title=Sexual Selection and Sexual Dimorphism in the Harlequin Beetle ''Acrocinus longimanus'' |journal=Biotropica |volume=24 |issue=1 |pages=86–96 |doi=10.2307/2388476|jstor=2388476 |bibcode=1992Biotr..24...86Z }}</ref> [[Rhaphidophoridae|Camel crickets]] use spines on their tibias for two reasons; (1) to fight other males for access to females, and (2) to pin mates as a form of [[Sexual coercion among animals|coercion]].<ref name="Lane2018"></ref><ref name="Haley2011">{{Cite journal |last1=Haley |first1=Estenia L. |last2=Gray |first2=David A. |title=Mating Behavior and Dual-Purpose Armaments in a Camel Cricket |url=https://onlinelibrary.wiley.com/doi/full/10.1111/j.1439-0310.2011.01985.x |journal=Ethology |date=2011-11-09 |language=en |volume=118 |issue=1 |pages=49–56 |doi=10.1111/j.1439-0310.2011.01985.x |url-access=subscription }}</ref> Among arthropods that are not insects, male [[Fiddler crab|fiddler crabs]] have large [[claws]] that comprise half their body mass and are used to attract mates elaborate waving displays with the claw.<ref>Perez, D. M., Rosenberg, M. S., and Pie, M. R., 2012, The evolution of waving displays in fiddler crabs (Uca spp., Crustacea: Ocypodidae): Biological Journal of the Linnean Society, v. 106, p. 307-315.</ref> They are also, though somewhat less commonly, used as a weapon to directly attack other males.<ref>Callander, S., Kahn, A. T., Maricic, T., Jennions, M. D., and Backwell, P. R. Y., 2013, Weapons or mating signals? Claw shape and mate choice in a fiddler crab: Behavioral Ecology and Sociobiology, v. 67, p. 1163-1167.</ref><ref name="Emlen2008"></ref>