Editing Mantis shrimp (section)

===Claws===
The mantis shrimp's second pair of thoracic appendages is adapted for powerful close-range combat. These claws can accelerate at a rate comparable to that of a [[.22 caliber]] bullet when fired, having around 1500 newtons of force with each swing/attack.<ref>{{cite web | url=https://sites.nd.edu/biomechanics-in-the-wild/2019/03/05/how-the-mantis-shrimp-packs-its-punch/#:~:text=The%20mantis%20shrimp%2C%20a%20six%20inch%20long%20crustacean,around%201500%20newtons%20of%20force%20with%20each%20blow | title=How the Mantis Shrimp Packs its Punch &#124; Biomechanics in the Wild }}</ref> The appendage differences divide mantis shrimp into two main types: those that hunt by impaling their prey with spear-like structures and those that smash prey with a powerful blow from a heavily mineralised club-like appendage. A considerable amount of damage can be inflicted after impact with these robust, hammer-like claws. This club is further divided into three subregions: the impact region, the periodic region, and the striated region. Mantis shrimp are commonly separated into distinct groups (most are categorized as either spearers or smashers but there are some outliers)<ref>{{Cite web |title=Why are Mantis Shrimp so Awesome? |url=https://www.calacademy.org/explore-science/why-are-mantis-shrimp-so-awesome |access-date=2022-07-21 |website=California Academy of Sciences |language=en |archive-date=2022-08-10 |archive-url=https://web.archive.org/web/20220810083818/https://calacademy.org/explore-science/why-are-mantis-shrimp-so-awesome |url-status=live }}</ref> as determined by the type of claws they possess:

* '''Spearers''' are armed with spiny appendages - the spines having barbed tips - used to stab and snag prey. These raptorial appendages resemble those of [[Mantis|praying mantids]], hence the common name of these crustaceans. This is the type found in most mantis shrimp.<ref name="evo">{{cite journal |last1=Anderson |first1=Philip S.L. |last2=Claverie |first2=Thomas |last3=Patek |first3=S.N. |date=2014-07-01 |title=Levers and linkages: mechanical trade-offs in a power-amplified system |url=https://academic.oup.com/evolut/article/68/7/1919/6852628 |journal=Evolution |volume=68 |issue=7 |pages=1919–1933 |doi=10.1111/evo.12407 |pmid=24635148 |access-date=2025-01-08}}</ref>
* '''Smashers''' possess a much more developed club and a more rudimentary spear (which is nevertheless quite sharp and still used in fights between their own kind); the club is used to bludgeon and smash their prey apart. The inner aspect of the terminal portion of the appendage can also possess a sharp edge, used to cut prey while the mantis shrimp swims. This is found in the families Gonodactylidae, Odontodactylidae, Protosquillidae, and Takuidae.<ref name="evo"/>
* '''Spike smashers (hammers or primitive smashers)''': An unspecialized form, found only in the basal family Hemisquillidae. The last segment lacks spines except at the tip, so it is not as effective at spearing but can also be used for smashing.<ref name="evo"/><ref name=":1" /><ref name=":2" /><ref>{{Cite web |title=h_californiensis |url=https://ucmp.berkeley.edu/arthropoda/crustacea/malacostraca/eumalacostraca/royslist/species.php?name=h_californiensis |access-date=2022-07-21 |website=ucmp.berkeley.edu |archive-date=2023-04-18 |archive-url=https://web.archive.org/web/20230418023755/https://ucmp.berkeley.edu/arthropoda/crustacea/malacostraca/eumalacostraca/royslist/species.php?name=h_californiensis |url-status=live }}</ref>
* '''Hatchet''': An unusual, highly derived appendage that only a few species have. This body plan is largely unresearched.<ref name=":1">{{Cite web |title=How mantis shrimp evolved many shapes with same powerful punch |url=https://phys.org/news/2015-02-mantis-shrimp-evolved-powerful.html |access-date=2022-07-21 |website=phys.org |language=en |archive-date=2022-07-21 |archive-url=https://web.archive.org/web/20220721161949/https://phys.org/news/2015-02-mantis-shrimp-evolved-powerful.html |url-status=live }}</ref><ref name=":2">{{Cite web |title=Roy's List of Stomatopods for the Aquarium |url=https://ucmp.berkeley.edu/arthropoda/crustacea/malacostraca/eumalacostraca/royslist/ |access-date=2022-07-21 |website=ucmp.berkeley.edu |archive-date=2022-08-23 |archive-url=https://web.archive.org/web/20220823173035/https://ucmp.berkeley.edu/arthropoda/crustacea/malacostraca/eumalacostraca/royslist/ |url-status=live }}</ref><ref>{{Cite web |title=a_derijardi |url=https://ucmp.berkeley.edu/arthropoda/crustacea/malacostraca/eumalacostraca/royslist/species.php?name=a_derijardi |access-date=2022-07-21 |website=ucmp.berkeley.edu |archive-date=2022-01-31 |archive-url=https://web.archive.org/web/20220131024528/https://ucmp.berkeley.edu/arthropoda/crustacea/malacostraca/eumalacostraca/royslist/species.php?name=a_derijardi |url-status=live }}</ref>

[[File:20220123 stomatopod strike mechanics spearing en.gif|thumb|Strike mechanics and spearing movement of the second [[maxilliped]] (raptorial claw, ballistic claw) of mantis shrimp]]
Both types strike by rapidly unfolding and swinging their [[raptorial]] claws at the prey, and can inflict serious damage on victims significantly greater in size than themselves. In smashers, these two weapons are employed with blinding quickness, with an acceleration of 10,400&nbsp;[[g-force|''g'']] (102,000&nbsp;m/s<sup>2</sup> or 335,000&nbsp;ft/s<sup>2</sup>) and speeds of {{cvt|23|m/s|km/h mph|lk=on}} from a standing start.<ref name="Patek et al">{{cite journal |author=S. N. Patek, W. L. Korff & R. L. Caldwell |year=2004 |journal=[[Nature (journal)|Nature]] |volume=428 |pages=819–820 |title=Deadly strike mechanism of a mantis shrimp |doi=10.1038/428819a |pmid=15103366 |issue=6985 |bibcode=2004Natur.428..819P |s2cid=4324997 |url=https://pateklab.biology.duke.edu/sites/pateklab.biology.duke.edu/files/Pateketal2004Nature.pdf |access-date=2017-05-02 |archive-date=2021-01-26 |archive-url=https://web.archive.org/web/20210126130108/https://pateklab.biology.duke.edu/sites/pateklab.biology.duke.edu/files/Pateketal2004Nature.pdf |url-status=dead}}</ref> Because they strike so rapidly, they generate vapor-filled bubbles in the water between the appendage and the striking surface—known as [[cavitation]] bubbles.<ref name="Patek et al"/> The collapse of these cavitation bubbles produces measurable forces on their prey in addition to the instantaneous forces of 1,500&nbsp;[[Newton (unit)|newtons]] that are caused by the impact of the appendage against the striking surface, which means that the prey is hit twice by a single strike; first by the claw and then by the collapsing cavitation bubbles that immediately follow.<ref name="Patek and Caldwell">{{cite journal |author1=S. N. Patek |author2=R. L. Caldwell |name-list-style=amp |year=2005 |journal=[[Journal of Experimental Biology]] |volume=208 |pages=3655–3664 |title=Extreme impact and cavitation forces of a biological hammer: strike forces of the peacock mantis shrimp |doi=10.1242/jeb.01831 |pmid=16169943 |issue=19 |doi-access=free}}</ref> Even if the initial strike misses the prey, the resulting [[shock wave]] can be enough to stun or kill.

Smashers use this ability to attack [[crab]]s, [[snail]]s, [[rock oyster]]s, and other [[Mollusca|molluscs]], their blunt clubs enabling them to crack the shells of their prey into pieces. Spearers, however, prefer the meat of softer animals, such as [[fish]] and [[cephalopod]]s, which their barbed claws can more easily slice and snag.

The appendages are being studied as a microscale analogue for new macroscale material structures.<ref name=20160601_SD>{{cite news |title=Mantis shrimp inspires next generation of ultra-strong materials |url=https://www.spacedaily.com/reports/Mantis_shrimp_inspires_next_generation_of_ultra_strong_materials_999.html |work=Space Daily |date=June 1, 2016 |access-date=May 13, 2020 |archive-date=May 24, 2021 |archive-url=https://web.archive.org/web/20210524171606/https://www.spacedaily.com/reports/Mantis_shrimp_inspires_next_generation_of_ultra_strong_materials_999.html |url-status=live }}</ref>{{Clarify|date=January 2025}}