moray eel

The dorsal fin extends from just behind the head along the back and joins seamlessly with the caudal and anal fins. Most species lack pectoral and pelvic fins, adding to their serpentine appearance. Their eyes are rather small; morays rely mostly on their highly developed sense of smell, lying in wait to ambush prey.{{cite web |date=2019-08-16 |title=Crazy facts about the moray eel |department=Moray eels |series=Marine Life Guide |website=Khao Lak Explorer (khaolakexplorer.com) |quote=Liveaboard to Similan Islands |url=https://www.khaolakexplorer.com/marine-life-guide/moray-eels/ |access-date=2021-06-17 |lang=en}}

The body is generally patterned. In some species, the inside of the mouth is also patterned. Their jaws are wide, framing a protruding snout. Most possess large teeth used to tear flesh or grasp slippery prey. A relatively small number of species, for example the snowflake moray (Echidna nebulosa) and zebra moray (Gymnomuraena zebra), primarily feed on crustaceans and other hard-shelled animals, and they have blunt, molar-like teeth suitable for crushing.{{cite book |last=Randall |first=J.E. |year=2005 |title=Reef and Shore Fishes of the South Pacific |publisher=University of Hawai'i Press |isbn=0-8248-2698-1 }}

Morays secrete a protective mucus over their smooth, scaleless skin, which in some species contains a toxin. They have much thicker skin and high densities of goblet cells in the epidermis that allows mucus to be produced at a higher rate than in other eel species. This allows sand granules to adhere to the sides of their burrows in sand-dwelling morays,{{cite journal |last=Fishelson |first=L. |date=September 1996 |title=Skin morphology and cytology in marine eels adapted to different lifestyles |journal=The Anatomical Record |volume=246 |issue=1 |pages=15–29 |pmid=8876820 |doi=10.1002/(SICI)1097-0185(199609)246:1<15::AID-AR3>3.0.CO;2-E |doi-access=free }} thus making the walls of the burrow more permanent due to the glycosylation of mucins in mucus. Placement of their small, circular gills on their flanks, far behind the mouth, requires the moray to maintain a gape / gulping motion to facilitate respiration.{{clarification needed|date=March 2023}}

The pharyngeal jaws of morays are located farther back in the head and closely resemble the oral jaws (complete with tiny "teeth"). When feeding, morays launch these jaws into the mouth cavity, where they grasp prey and transport it into the throat. Moray eels are the only known animals that use pharyngeal jaws to actively capture and restrain prey in this way.{{cite journal |vauthors=Mehta RS, Wainwright PC |date=September 2007 |title=Raptorial jaws in the throat help moray eels swallow large prey |journal=Nature |volume=449 |issue=7158 |pages=79–82 |pmid=17805293 |doi=10.1038/nature06062 |bibcode=2007Natur.449...79M |s2cid=4384411 }}{{cite news |last=Hopkin |first=Michael |date=2007-09-05 |title=Eels imitate Alien: Fearsome fish have protruding jaws in their throats to grab prey |journal=Nature News |doi=10.1038/news070903-11 |s2cid=85118599 |url=http://www.nature.com/news/2007/070903/full/070903-11.html |access-date=2007-09-06}}{{cite press release |title=Moray eels are uniquely equipped to pack big prey into their narrow bodies |website=nsf.gov/news |publisher=U.S. National Science Foundation (NSF) |url=https://www.nsf.gov/news/news_summ.jsp?cntn_id=109985&org=NSF |access-date=11 December 2016}}File:Pharyngeal jaws of moray eels.svg In addition to the presence of pharyngeal jaws, morays' mouth openings extend far back into the head, compared to fish which feed using suction. In the action of lunging at prey and biting down, water flows out the posterior side of the mouth opening, reducing waves in front of the eel which would otherwise displace prey. Thus, aggressive predation is still possible even with reduced bite times.{{cite journal |vauthors=Mehta RS, Wainwright PC |date=February 2007 |title=Biting releases constraints on moray eel feeding kinematics |journal=The Journal of Experimental Biology |volume=210 |issue=Part 3 |pages=495–504 |pmid=17234619 |doi=10.1242/jeb.02663 |doi-access=free |bibcode=2007JExpB.210..495M }} In at least one species, the California moray (Gymnothorax mordax), teeth in the roof of the mouth are able to fold down as prey slides backwards, thus preventing the teeth from breaking and maintaining a hold on prey as it is transported to the throat.

Differing shapes of the jaw and teeth reflect the respective diets of different species of moray eel. Evolving separately multiple times within the Muraenidae family, short, rounded jaws and molar-like teeth allow durophagous eels (e.g. zebra moray and genus Echidna) to consume crustaceans, while other piscivorous genera of Muraenidae have pointed jaws and longer teeth.{{cite journal | vauthors = Reece JS, Bowen BW, Smith DG, Larson A | date = November 2010 | title = Molecular phylogenetics of moray eels (Muraenidae) demonstrates multiple origins of a shell-crushing jaw (Gymnomuraena, Echidna) and multiple colonizations of the Atlantic Ocean | journal = Molecular Phylogenetics and Evolution | volume = 57 | issue = 2 | pages = 829–35 | pmid = 20674752 | doi = 10.1016/j.ympev.2010.07.013 | bibcode = 2010MolPE..57..829R }}{{cite journal | vauthors = Mehta RS | title = Ecomorphology of the moray bite: relationship between dietary extremes and morphological diversity | journal = Physiological and Biochemical Zoology | volume = 82 | issue = 1 | pages = 90–103 | date = January 2009 | pmid = 19053846 | doi = 10.1086/594381 | s2cid = 19640346 }}{{cite journal | vauthors = Collar DC, Reece JS, Alfaro ME, Wainwright PC, Mehta RS | date = June 2014 | title = Imperfect morphological convergence: variable changes in cranial structures underlie transitions to durophagy in moray eels | journal = The American Naturalist | volume = 183 | issue = 6 | pages = E168–184 | pmid = 24823828 | doi = 10.1086/675810 | bibcode = 2014ANat..183E.168C | s2cid = 17433961 }} These morphological patterns carry over to teeth positioned on the pharyngeal jaw.{{Cite book |title=Fishes of the Western North Atlantic |section=Part 9: Orders Anguilliformes and Saccopharyngiformes |editor-last=Böhlke |editor-first=Eugenia B. |year=1989 |location=New Haven, CT |series=Sears Foundation for marine research |publisher=Yale University |isbn=978-0935868456 |oclc=30092375}}{{cite book |last=Gregory |first=William K. |year=2002 |title=Fish Skulls: A study of the evolution of natural mechanisms |publisher=Krieger Pub |isbn=978-1575242149 |location=Malabar, FL |oclc=48892721 }}

File:GymnothoraxMiliarisCraniumClean.jpg

Morays are opportunistic, carnivorous predators{{Cite web |last=Kooser |first=Amanda |title=See a snowflake moray eel swallow a sushi snack in an extraordinary way |url=https://www.cnet.com/news/see-a-snowflake-moray-eel-swallow-a-snack-in-an-extraordinary-way/ |access-date=2021-06-17 |website=CNET |language=en}} and feed primarily on smaller fish, crabs, and octopuses.{{Cite journal |last1=Young |first1=Robert F. |last2=Winn |first2=Howard E. |date=February 2003 |title=Activity Patterns, Diet, and Shelter Site Use for Two Species of Moray Eels, Gymnothorax moringa and Gymnothorax vicinus, in Belize |url=https://bioone.org/journals/copeia/volume-2003/issue-1/0045-8511(2003)003[0044:APDASS]2.0.CO;2/Activity-Patterns-Diet-and-Shelter-Site-Use-for-Two-Species/10.1643/0045-8511(2003)003[0044:APDASS]2.0.CO;2.full |journal=Copeia |volume=2003 |issue=1 |pages=44–55 |doi=10.1643/0045-8511(2003)003[0044:APDASS]2.0.CO;2 |s2cid=85897128 |issn=0045-8511}} A spotted moray eel has been observed eating a red lionfish without harm.{{Cite journal |last1=Pimiento |first1=Catalina |last2=Monaco |first2=Eric |last3=Barbour |first3=Andrew B. |last4=Silliman |first4=Brian R. |title=Predation on Speared Red Lionfish, Pterois Volitans, by Spotted Moray, Gymnothorax Moringa |date=2013 |url=https://www.jstor.org/stable/24321994 |journal=Florida Scientist |volume=76 |issue=3/4 |pages=391–394 |jstor=24321994 |issn=0098-4590}}{{Cite web |last=June 2021 |first=Mindy Weisberger-Senior Writer 10 |title=These eels can swallow prey on land, thanks to extendable jaws in their throats |url=https://www.livescience.com/moray-extendable-jaws-land.html |access-date=2021-06-17 |website=livescience.com |date=10 June 2021 |language=en}} Groupers, barracudas and sea snakes are among their few known predators, making many morays (especially the larger species) apex predators in their ecosystems.{{Cite web |date=2020-07-10 |title=Moray Eel - Facts and Beyond |url=https://biologydictionary.net/moray-eel/ |access-date=2021-06-17 |website=Biology Dictionary |language=en-US}}

Reef-associated roving coral groupers (Plectropomus pessuliferus) have been observed recruiting giant morays to help them hunt. The invitation to hunt is initiated by head-shaking. This style of hunting may allow morays to flush prey from niches not accessible to groupers.In the December 2006 issue of the journal Public Library of Science Biology, a team of biologists announced the discovery of interspecies cooperative hunting involving morays. The biologists, who were engaged in a study of Red Sea cleaner fish (fish that enter the mouths of other fish to rid them of parasites), made the discovery.[http://www.livescience.com/animalworld/061207_fish_cooperation.html An Amazing First: Two Species Cooperate to Hunt | LiveScience]{{cite journal | vauthors = Bshary R, Hohner A, Ait-el-Djoudi K, Fricke H | title = Interspecific communicative and coordinated hunting between groupers and giant moray eels in the Red Sea | journal = PLOS Biology | volume = 4 | issue = 12 | pages = e431 | date = December 2006 | pmid = 17147471 | pmc = 1750927 | doi = 10.1371/journal.pbio.0040431 | doi-access = free }}Vail A.L., Manica A., Bshary R., [http://www.nature.com/articles/ncomms2781 Referential gestures in fish collaborative hunting], in Nature Communications, vol. 4, 2013.

File:Moray eel in Kona.JPG occupying a dead patch reef, located in Kona, Hawaii]]

The moray eel can be found in both fresh and saltwater habitats. The vast majority of species are strictly marine, never entering freshwater. Of the few species known to live in freshwater, the most well-known is Gymnothorax polyuranodon.{{Cite journal|last1=Ebner|first1=Brendan C.|last2=Fulton|first2=Christopher J.|last3=Donaldson|first3=James A.|last4=Schaffer|first4=Jason|date=2015|title=Distinct habitat selection by freshwater morays in tropical rainforest streams|journal=Ecology of Freshwater Fish|volume=25|issue=2|pages=329–335|doi=10.1111/eff.12213|issn=0906-6691|doi-access=free}}

File:Spotted moray eel.jpg occupying a live coral reef, located in Sabang, Philippines]]

Within the marine realm, morays are found in shallow water nearshore areas, continental slopes, continental shelves, deep benthic habitats, and mesopelagic zones of the ocean, and in both tropical and temperate environments.{{Cite journal|last1=Tsukamoto|first1=Katsumi|last2=Watanabe|first2=Shun|last3=Kuroki|first3=Mari|last4=Aoyama|first4=Jun|last5=Miller|first5=Michael J.|date=2014|title=Freshwater habitat use by a moray eel species, Gymnothorax polyuranodon, in Fiji shown by otolith microchemistry|journal=Environmental Biology of Fishes|volume=97|issue=12|pages=1377–1385|doi=10.1007/s10641-014-0228-9|bibcode=2014EnvBF..97.1377T |s2cid=7596020|issn=0378-1909}} Most species are found in tropical or subtropical environments, with only a few species (yellow moray) found in temperate ocean environments.

Although the moray eel can occupy both tropical oceans and temperate oceans, as well as both freshwater and saltwater, the majority of moray eels occupy warm saltwater environments, which contain reefs.{{Cite journal|last1=Young|first1=Robert F.|last2=Winn|first2=Howard E.|last3=Montgomery|first3=W. L.|date=2003|title=Activity Patterns, Diet, and Shelter Site Use for Two Species of Moray Eels, Gymnothorax moringa and Gymnothorax vicinus, in Belize|journal=Copeia|volume=2003|issue=1|pages=44–55|doi=10.1643/0045-8511(2003)003[0044:APDASS]2.0.CO;2|s2cid=85897128 |issn=0045-8511}} Within the tropical oceans and temperate oceans, the moray eel occupies shelters, such as dead patch reefs and coral rubble rocks, and less frequently occupies live coral reefs.

File:Moray4.jpg

File:Gymnomuraena_marmorata_Achilles_172.jpg

There are about 202 known species of moray eels, in 16 genera. These genera are in two sub-families, Muraeninae and Uropterygiinae, which are distinguished by the location of their fins.{{cite journal |last=Reece |first=Joshua |date=January 2010 |title=Phylogenetics and phylogeography of moray eels (Muraenidae) |journal=Washington University Open Scholarship |url=https://openscholarship.wustl.edu/cgi/viewcontent.cgi?article=1289&context=etd |via=openscholarship.wustl.edu }} In Muraeninae the dorsal fin is near the gill slits and runs down the back of the eel, and the anal fin is behind the anus. In the Uropterygiinnae, both the dorsal and the anal fin are at the end of the tail. Though this distinction can be seen between the two sub-families, there are still many varieties of genera within Muraeninae and Uropterygiinae. Of these, the genus Gymnothorax is by far the broadest, including more than half of the total number of species.

The family Muraenidae comprises the following subfamiles and genera:{{Cof family|family=Muraenidae|access-date=10 November 2024}}

• Subfamily Muraeninae Rafinesque, 1815
• Diaphenchelys McCosker & Randall, 2007
• Echidna Forster, 1788
• Enchelycore Kaup, 1856
• Enchelynassa Kaup, 1855
• Gymnomuraena Lacepède, 1803
• ''Gymnothorax Bloch, 1795
• Monopenchelys Böhlke & McCosker, 1982
• Muraena Linnaeus, 1758
• Pseudechidna Bleeker, 1863
• Rhinomuraena Garman, 1888
• Strophidon McClelland, 1844
• Subfamily Uropterygiinae Fowler 1925
• Anarchias D. S. Jordan & Starks, 1906
• Channomuraena Richardson, 1848
• Cirrimaxilla H.-M. Chen & K.-T .Shao, 1995
• Scuticaria D. S. Jordan & Snyder, 1901
• Uropterygius Rüppell, 1838

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File:TakamayuUBf.jpg|Anarchias seychellensis

File:FMIB 47184 Gymomuraena vittata, from Cuba.jpeg|Channomuraena vittata

File:Echidna nebulosa Réunion.jpg|Snowflake moray (Echidna nebulosa)

File:Enchelycore schismatorhynchus.JPG|Enchelycore schismatorhynchus

File:FMIB 42381 Enchelynassa vinolentus (Jordan & Evermann).jpeg|Viper moray (Enchelynassa canina)

File:Gymnomuraena zebra by NPS.jpg|Zebra moray (Gymnomuraena zebra)

File:Laced Moray.jpg|Laced moray (Gymnothorax favagineus)

File:Gymnothorax rueppelliae Réunion.JPG|Gymnothorax rueppelliae

File:Monopenchelys acuta - pone.0010676.g012.png|Monopenchelys acuta

File:Muraena helena swimming v2.jpg|Mediterranean moray (Muraena helena)

File:Pseudechidna brummer).JPG|White ribbon eel (Pseudechidna brummeri)

File:Ribbon Moray (Rhinomuraena quaesita) (6052858389).jpg|Ribbon eel (Rhinomuraena quaesita)

File:Scuticaria tigrina.jpg|Scuticaria tigrina

File:Strophidon sathete.jpg|Slender giant moray (Strophidon sathete)

File:Uropterygius xanthopterus - 2.JPG|Uropterygius xanthopterus

File:Kidako moray.JPG|Kidako moray (Gymnothorax kidako)

The moray eel's elongation is due to an increase in the number of vertebrae, rather than a lengthening of each individual vertebra or a substantial decrease in body depth.{{Cite journal|last1=Mehta|first1=Rita S.|last2=Reece|first2=Joshua S.|date=July 2013|title=Evolutionary history of elongation and maximum body length in moray eels (Anguilliformes: Muraenidae)|journal=Biological Journal of the Linnean Society|volume=109|issue=4|pages=861–875|doi=10.1111/bij.12098|doi-access=free}} Vertebrae have been added asynchronously between the pre-tail ("precaudal") and tail ("caudal") regions, unlike other groups of eels such as Ophicthids and Congrids.{{cite journal | vauthors = Mehta RS, Ward AB, Alfaro ME, Wainwright PC | title = Elongation of the body in eels | journal = Integrative and Comparative Biology | volume = 50 | issue = 6 | pages = 1091–105 | date = December 2010 | pmid = 21558261 | doi = 10.1093/icb/icq075 | url = https://academic.oup.com/icb/article/50/6/1091/633110 | doi-access = free }}

Several moray species are popular among aquarium hobbyists for their hardiness, flexible diets, and disease resistance. The most commonly traded species are the snowflake, zebra and goldentail moray (Gymnothorax miliaris). Several other species are occasionally seen, but are more difficult to obtain and can command a steep price on the market.{{Cite web|url=http://www.tfhmagazine.com/saltwater-reef/feature-articles/morays.htm|title=Morays!|first=Mike|last=Maddox|website=TFH Magazine|access-date=2018-08-29}}

{{main|Ciguatera fish poisoning}}

Moray eels, particularly the giant moray (Gymnothorax javanicus) and yellow-edged moray (G. flavimarginatus), are known to accumulate high levels of ciguatoxins, unlike other reef fish;{{cite journal | vauthors = Chan TY | title = Characteristic Features and Contributory Factors in Fatal Ciguatera Fish Poisoning--Implications for Prevention and Public Education | journal = The American Journal of Tropical Medicine and Hygiene | volume = 94 | issue = 4 | pages = 704–9 | date = April 2016 | pmid = 26787145 | pmc = 4824207 | doi = 10.4269/ajtmh.15-0686 }}{{cite journal | vauthors = Chan TY | title = Regional Variations in the Risk and Severity of Ciguatera Caused by Eating Moray Eels | journal = Toxins | volume = 9 | issue = 7 | pages = 201 | date = June 2017 | pmid = 28672845 | pmc = 5535148 | doi = 10.3390/toxins9070201 | doi-access = free }} if consumed by humans, ciguatera fish poisoning may result. Ciguatera is characterised by neurological, gastrointestinal, and cardiovascular problems that may persist for days after eating tainted fish. In morays, the toxins are most concentrated in the liver. In an especially remarkable instance, 57 people in the Northern Mariana Islands were poisoned after eating just the head and half of a cooked yellow-edged moray.{{Cite journal|last=Khlentzos|first=Constantine T.|date=1950-09-01|title=Seventeen Cases of Poisoning Due to Ingestion of an Eel, Gymnothorax Flavimarginatus 1|journal=The American Journal of Tropical Medicine and Hygiene|volume=s1-30|issue=5|pages=785–793|doi=10.4269/ajtmh.1950.s1-30.785|pmid=14771403|issn=0002-9637}} Thus, morays are not recommended for human consumption.

{{Reflist}}

• Gross, Miriam J.. The Moray Eel. United States: Rosen Publishing Group's PowerKids Press, 2005.
• Purser, Phillip. Keeping Moray Eels in Aquariums. United States: T.F.H., 2005.
• Didier, Dominique A.. Moray Eel. United States: Cherry Lake Publishing, 2014.
• Goldish, Meish. Moray Eel: Dangerous Teeth. United Kingdom: Bearport Publishing, 2009.

{{Commons category|Muraenidae}}

{{NIE Poster|year=1905|Moray}}

• [https://web.archive.org/web/20141025030848/http://www.marbef.org/modules.php?name=News&file=article&sid=198 Moray Eels Grab Prey With Alien Jaws]
• Smith, J.L.B. 1962. [http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:14991?site_name=GlobalView The moray eels of the Western Indian Ocean and the Red Sea. Ichthyological Bulletin; No. 23]. Department of Ichthyology, Rhodes University, Grahamstown, South Africa.

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Category:Extant Miocene first appearances

Category:Taxa named by Constantine Samuel Rafinesque