Editing Vampire squid

{{Short description|Species of cephalopod}}
{{Speciesbox
 | image             = Vampyroteuthis illustration.jpg
 | image_caption     = 
 | status            = 
 | status_system     = 
 | status_ref        = 
 | genus             = Vampyroteuthis
 | parent_authority  = [[Carl Chun|Chun]], 1903
 | species           = infernalis
 | authority         = [[Carl Chun|Chun]], 1903
 | synonyms          = {{Specieslist
 |Cirroteuthis macrope|[[Samuel Stillman Berry|Berry]], 1911
 |Danateuthis schmidti|[[Louis Joubin|Joubin]], 1929
 |Hansenoteuthis lucens|Joubin, 1929
 |Melanoteuthis anderseni|Joubin, 1931
 |Melanoteuthis beebei|[[Guy Coburn Robson|Robson]], 1929
 |Melanoteuthis lucens|Joubin, 1912
 |Melanoteuthis schmidti|Joubin, 1929
 |Retroteuthis pacifica|Joubin, 1929
 |Watasella nigra|[[Madoka Sasaki|Sasaki]], 1920
 }}
 | synonyms_ref      = <ref name = MolluscaBase>{{cite web | author = Philippe Bouchet | year = 2018 | title = ''Vampyroteuthis infernalis'' Chun, 1903 | url = http://www.molluscabase.org/aphia.php?p=taxdetails&id=141887 | access-date = 19 March 2021 | website = MolluscaBase}}</ref>
}}

The '''vampire squid''' ('''''Vampyroteuthis infernalis''''', lit. 'vampire squid from hell') is a small [[cephalopod]] found throughout temperate and tropical oceans in extreme [[deep sea]] conditions.<ref>{{Cite journal |last1=Herring |first1=P. J. |last2=Dilly |first2=P. N. |last3=Cope |first3=Celia |date=1994-05-01 |title=The bioluminescent organs of the deep-sea cephalopod Vampyroteuthis infernalis (Cephalopoda: Vampyromorpha) |url=https://zslpublications.onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.1994.tb05261.x |journal=Journal of Zoology |language=en |volume=233 |issue=1 |pages=45–55 |doi=10.1111/j.1469-7998.1994.tb05261.x |issn=0952-8369|url-access=subscription }}</ref><ref>{{cite web|title=Vampire Squid, Vampyroteuthis infernalis|url=http://marinebio.org/species.asp?id=179|website=MarineBio.org}}</ref> The vampire squid uses its [[Bioluminescence|bioluminescent]] organs and its unique oxygen metabolism to thrive in the parts of the ocean with the lowest concentrations of oxygen. It has two long retractile filaments, located between the first two pairs of arms on its dorsal side,<ref name=":2">{{Cite journal |last=Young |first=Richard E. |date=1967 |title=Homology of Retractile Filaments of Vampire Squid |url=https://www.jstor.org/stable/1721610 |journal=Science |volume=156 |issue=3782 |pages=1633–1634 |doi=10.1126/science.156.3782.1633 |jstor=1721610 |pmid=6025124 |bibcode=1967Sci...156.1633Y |s2cid=24349161 |issn=0036-8075|url-access=subscription }}</ref> which distinguish it from both [[octopus]]es and [[squid]]s, and places it in its own order, [[Vampyromorphida]], although its closest relatives are octopods. As a [[phylogeny|phylogenetic]] [[Relict (biology)|relict]], it is the only known surviving member of its order.<ref>{{Cite journal|last1=Yokobori|first1=Shin-ichi|last2=Lindsay|first2=Dhugal J.|last3=Yoshida|first3=Mari|last4=Tsuchiya|first4=Kotaro|last5=Yamagishi|first5=Akihiko|last6=Maruyama|first6=Tadashi|last7=Oshima|first7=Tairo|date=August 2007|title=Mitochondrial genome structure and evolution in the living fossil vampire squid, Vampyroteuthis infernalis, and extant cephalopods|journal=Molecular Phylogenetics and Evolution|language=en|volume=44|issue=2|pages=898–910|doi=10.1016/j.ympev.2007.05.009|pmid=17596970|bibcode=2007MolPE..44..898Y }}</ref>

The first specimens were collected on the [[Valdivia Expedition]] and were originally [[Species description|described]] as an octopus in 1903 by German [[Teuthology|teuthologist]] [[Carl Chun]], but later assigned to a new order together with several extinct [[Taxon|taxa]].

==Etymology==
The [[genus]] name ''Vampyroteuthis'' comes from [[Latin]] ''vampyrus'', meaning [[vampire]], and [[Ancient Greek]] τευθίς (''teuthís''), meaning "squid". The [[species]] name "infernalis" means "of hell" in [[Latin]].

==Discovery==
The vampire squid was discovered during the Valdivia Expedition (1898–1899), led by Carl Chun. Chun was a zoologist who was inspired by the [[Challenger Expedition]], and wanted to verify that life does indeed exist below {{convert|300|fathom|m|abbr=off|sp=us}}.<ref>{{cite web |date=2020-06-04 |title=The Valdivia Expedition: Carl Chun's diving into the deep sea |url=https://www.sensesatlas.com/illustration/the-valdivia-expedition-carl-chuns-diving-into-the-deep-see/ |access-date=2020-10-29 |website=Senses Atlas |language=en-US}}</ref> Chun later classified the vampire squid into its family, [[Vampyroteuthidae]].<ref name=":2"/> This expedition was funded by the German society ''[[Gesellschaft Deutscher Naturforscher und Ärzte]]'', a group of German scientists who believed there was life at depths greater than 550&nbsp;meters, contrary to the [[Azoic hypothesis|Abyssus theory]]. {{SS|Valdivia|1886|2}} was fitted with equipment for the collection of deep-sea organisms, as well as laboratories and specimen jars, in order to analyze and preserve what was caught. The voyage began in Hamburg, Germany, followed by Edinburgh, and then traced around the west coast of Africa. After navigating around the southern point of Africa, the expedition studied deep areas of the Indian and Antarctic Ocean.<ref>{{cite journal |date=1898 |title=The German Deep-Sea Expedition |url=https://www.jstor.org/stable/1774523 |journal=[[The Geographical Journal]] |volume=12 |issue=5 |pages=494–496 |doi=10.2307/1774523 |jstor=1774523 |bibcode=1898GeogJ..12..494. |issn=0016-7398|url-access=subscription }}</ref> Researchers had not before discovered any species from this family that could be traced back to the Cenozoic. This suggests two ideas which are: a notable preservation bias called the [[Lazarus taxon|Lazarus effect]] may exist; or an inaccurate determination of when vampire squids originally settled in the deep oceans. The Lazarus effect may result from the scarcity of post-Cretaceous research regions or from the reduced abundance and distribution of vampire squids. In any case, even while the search regions remain the same, it is more difficult to locate and analyze them.<ref>{{ Cite journal| title= Fossil evidence for vampire squid inhabiting oxygen-depleted ocean zones since at least the Oligocene | first1= Martin |last1=Košťák |first2=Ján |last2=Schlögl |first3=Dirk |last3=Fuchs |first4=Katarína |last4=Holcová |first5=Natalia |last5=Hudáčková |first6=Adam |last6=Culka |first7=István |last7=Fözy |first8=Adam |last8=Tomašových |first9=Rastislav |last9=Milovský |first10=Juraj |last10=Šurka |first11=Martin |last11=Mazuch1| journal=Communications Biology |date=February 18, 2021 | volume= 4 | issue= 1 | page= 216 |doi=10.1038/s42003-021-01714-0 |pmc=7893013 |pmid=33603225 }}</ref><ref name=":0"/>

==Description==
The vampire squid can reach a maximum total length around {{convert|30|cm|ft|0|abbr=on}}. Its {{convert|15|cm|in|adj=on}} gelatinous body varies in colour from velvety jet-black to pale reddish, depending on location and lighting conditions.{{Clarify|reason=Could the chromatophores play a role in this color-shifting?|date=October 2024}} A webbing of skin connects its eight arms, each lined with rows of fleshy spines or [[cirrus (biology)|cirri]]; the inner side of this "cloak" is black. Only the distal halves (farthest from the body) of the arms have suckers. The name of the animal was inspired by its dark colour and cloaklike webbing, rather than its habits — it feeds on [[marine snow|detritus]], not [[Hematophagy|blood]].<ref name="NOAA">{{cite web |title=The vampire squid and the vampire fish |url=https://oceanservice.noaa.gov/facts/vampire-squid-fish.html#:~:text=Its%20huge%2C%20bright%20blue%20eyes,%E2%80%9Cvampire%20squid%20of%20Hell%E2%80%9D! |website=National Ocean Service |access-date=22 December 2023}}</ref><ref>{{cite web |url= http://www.thecephalopodpage.org/vampy.php |title=''Vampyroteuthis infernalis'', Deep-sea Vampire squid |work=The Cephalopod Page |publisher=Dr. James B. Wood |access-date=3 July 2011}}</ref><ref name=":0"/>

[[File:Vampyroteuthis infernalis dorsal view.jpg|thumb|left|Dorsal view]]

Its [[wiktionary:limpid#adjective|limpid]], globular eyes, which appear red or blue, depending on lighting, are proportionately the largest in the animal kingdom, with a {{convert|6|in|cm}} squid possessing eyes {{convert|2.5|cm|in|0|abbr=on}} in diameter.<ref>{{cite web|url= http://www.thecephalopodpage.org/vsfh.php |title=Introducing ''Vampyroteuthis infernalis'', the vampire squid from Hell |work=The Cephalopod Page |publisher=Dr. James B. Wood |access-date=27 April 2012}}</ref> Their large eyes are accompanied by the similarly expanded optic lobes of their brain.<ref name="VisBrain">{{Cite journal|last1=Chung|first1=Wen-Sung|last2=Kurniawan|first2=Nyoman D.|last3=Marshall|first3=N. Justin|date=2021-11-18|title=Comparative brain structure and visual processing in octopus from different habitats|journal=Current Biology|volume=32 |issue=1 |pages=97–110.e4 |language=English|doi=10.1016/j.cub.2021.10.070|issn=0960-9822|pmid=34798049|s2cid=244398601|doi-access=free}}</ref>

[[File:Vampyroteuthis infernalis arms.jpg|thumb|left|Oral view]]

Mature adults have a pair of [[Cephalopod fin|small fins]] projecting from the lateral sides of the [[mantle (mollusc)|mantle]]. These earlike fins serve as the adult's primary means of propulsion: vampire squid [[Aquatic locomotion|move through the water]] by flapping their fins. Their [[Cephalopod beak|beaklike jaws]] are white. Within the webbing are two pouches wherein the tactile velar filaments are concealed. The filaments are analogous to a true squid's [[tentacle]]s, extending well past the [[cephalopod arm|arm]]s; but differ in origin, and represent the pair that was lost by the ancestral octopus.

The vampire squid is almost entirely covered in light-producing organs called [[photophore]]s, capable of producing disorienting flashes of light ranging in duration from fractions of a second to several minutes. The intensity and size of the photophores can also be modulated. Appearing as small, white discs, the photophores are larger and more complex at the tips of the arms and at the base of the two fins, but are absent from the undersides of the caped arms. Two larger, white areas on top of the head were initially believed to also be photophores, but are now identified as [[Simple eyes in invertebrates|photoreceptor]]s.{{Citation needed|date=October 2024}}

The [[chromatophore]]s (pigment organs) common to most [[cephalopod]]s are poorly developed in the vampire squid. The animal is, therefore, incapable of changing its skin colour in the dramatic fashion of shallow-dwelling cephalopods, as such an ability would not be useful at the lightless depths where it lives.

===Systematics===
[[Image:Vampylarge.JPG|thumb|[[Pyritization|Pyritized]] fossil of ''[[Vampyronassa|Vampyronassa rhodanica]]'' from the Lower [[Callovian]] of [[La Voulte-sur-Rhône (lagerstätte)|La Voulte-sur-Rhône]].]]

The Vampyromorphida is the extant sister taxon to all octopuses. Phylogenetic studies of cephalopods using multiple genes and mitochondrial genomes have shown that the Vampyromorphida are the first group of [[Octopodiformes]] to evolutionarily diverge from all others.<ref>{{Cite journal|last1=Uribe|first1=Juan E.|last2=Zardoya|first2=Rafael|date=May 1, 2017|title=Revisiting the phylogeny of Cephalopoda using complete mitochondrial genomes |url=https://academic.oup.com/mollus/article/83/2/133/2967092|journal=Journal of Molluscan Studies|volume=83|issue=2|pages=133–144|doi=10.1093/mollus/eyw052|via=academic.oup.com|doi-access=free|hdl=10261/156228|hdl-access=free}}</ref><ref name="auto2">{{Cite journal|last1=Lindgren|first1=Annie R.|last2=Pankey|first2=Molly S.|last3=Hochberg|first3=Frederick G.|last4=Oakley|first4=Todd H.|date=July 28, 2012|title=A multi-gene phylogeny of Cephalopoda supports convergent morphological evolution in association with multiple habitat shifts in the marine environment|journal=BMC Evolutionary Biology|volume=12|issue=1|pages=129 |doi=10.1186/1471-2148-12-129|pmc=3733422|pmid=22839506 |doi-access=free |bibcode=2012BMCEE..12..129L }}</ref><ref>{{Cite journal |last1=Strugnell |first1=Jan|last2=Nishiguchi|first2=Michele K.|date=November 1, 2007|title=Molecular phylogeny of coleoid cephalopods (Mollusca: Cephalopoda) inferred from three mitochondrial and six nuclear loci: a comparison of alignment, implied alignment and analysis methods|journal=Journal of Molluscan Studies|volume=73|issue=4 |pages=399–410|doi=10.1093/mollus/eym038|doi-access=free}}</ref> The Vampyromorphida is characterized by derived characters such as the possession of photophores and of two velar filaments which are most probably modified arms. It also shares the inclusion of an internal [[Gladius (cephalopod)|gladius]] with other [[Coleoidea|coleoids]], including squid, and eight webbed arms with [[Cirrina|cirrate]] octopods.

''Vampyroteuthis'' shares its eight cirrate arms with the Cirrata, in which lateral cirri, or filaments, alternate with the suckers. ''Vampyroteuthis'' differs in that suckers are present only on the distal half of the arms while cirri run the entire length. In cirrate octopods suckers and cirri run and alternate on the entire length. Also, a close relationship between ''Vampyroteuthis'' and the Jurassic-Cretaceous [[Loligosepiina]] is indicated by the similarity of their gladii, the internal stiffening structure. ''[[Vampyronassa|Vampyronassa rhodanica]]'' from the middle Jurassic [[La Voulte-sur-Rhône (lagerstätte)|La Voulte-sur-Rhône]] of France is considered as one of a vampyroteuthid that shares some characters with ''Vampyroteuthis''.<ref>{{Cite journal |last1=Rowe |first1=Alison J. |last2=Kruta |first2=Isabelle |last3=Landman |first3=Neil H. |last4=Villier |first4=Loïc |last5=Fernandez |first5=Vincent |last6=Rouget |first6=Isabelle |date=2022-06-23 |title=Exceptional soft-tissue preservation of Jurassic Vampyronassa rhodanica provides new insights on the evolution and palaeoecology of vampyroteuthids |journal=Scientific Reports |language=en |volume=12 |issue=1 |pages=8292 |doi=10.1038/s41598-022-12269-3 |pmid=35739131 |pmc=9225997 |bibcode=2022NatSR..12.8292R |issn=2045-2322|doi-access=free }}</ref>

The supposed vampyromorphids from the [[Kimmeridgian]]-[[Tithonian]] (156–146 mya) of [[Solnhofen]], ''[[Plesioteuthis prisca]]'', ''[[Leptotheuthis gigas]]'', and ''[[Trachyteuthis hastiformis]]'', cannot be positively assigned to this group; they are large species (from 35&nbsp;cm in ''P. prisca'' to > 1 m in ''L. gigas'') and show features not found in vampyromorphids, being somewhat similar to the true squids, [[Teuthida]].{{sfn|Fischer|Riou|2002}}

==Biology==
The vampire squid's [[Cosmopolitan distribution|worldwide range]] is confined to the [[tropics]] and [[subtropics]].<ref>{{cite web |title=Vampyroteithis infernalis |url=https://animaldiversity.org/accounts/Vampyroteuthis_infernalis/#:~:text=The%20vampire%20squid%20lives%20in,where%20virtually%20no%20light%20penetrates. |website=Animal Diversity Web |publisher=University of Michigan |access-date=5 March 2021}}</ref>{{Contradictory inline|reason=Lede states that it is also present in temperate waters|date=October 2024}} This species is an extreme example of a [[deep sea]] cephalopod, thought to reside at [[Aphotic zone|aphotic]] (lightless) depths from {{convert|600|to|900|m}} or more. Within this region of the world's oceans is a discrete [[habitat (ecology)|habitat]] known as the [[oxygen minimum zone]] (OMZ). Within an OMZ, the [[solubility|saturation]] of [[oxygen]] is too low to support aerobic [[metabolism]] in most complex organisms. The vampire squid is the only cephalopod able to live its entire life cycle in the minimum zone, at [[oxygen saturation]]s as low as 3%.

[[File:MBNMS juvenile vampire squid (49041024167).jpg|thumb|Juvenile vampire squid]]
What behavioral data is known has been gleaned from ephemeral encounters with [[remotely operated underwater vehicle]]s (ROV). Vampire squid are frequently injured during capture, and can survive up to two months in [[Aquarium|aquaria]]. It has been hypothesized that they can live for over eight years.{{sfn|Hoving |Laptikhovsky |Robison |2015}}

To cope with life in the suffocating depths, vampire squids have developed several adaptations: Of all deep-sea cephalopods, their mass-specific [[Metabolism|metabolic rate]] is the lowest. Their blue blood's [[hemocyanin]] binds and transports oxygen more efficiently than in other cephalopods,{{sfn|Seibel|Chausson|Lallier|Zal|1999}} aided by [[gill]]s possessing an especially large surface area. The animals have weak musculature and a greatly [[Gladius (cephalopod)|reduced shell]],<ref>[https://www.frontiersin.org/articles/10.3389/fmars.2022.909192/full The evolution of predator avoidance in cephalopods: A case of brain over brawn?]</ref> but maintain agility and buoyancy with little effort because of sophisticated [[statocyst]]s (balancing organs akin to a human's [[inner ear]]){{sfn|Stephens|Young|2009}} and [[ammonium]]-rich gelatinous tissues closely matching the [[density]] of the surrounding seawater. The vampire squid's ability to thrive in OMZs also keeps it safe from [[apex predator]]s that require a large amount of oxygen to live.{{sfn|Hoving|Robison|2012}}

The vampire squid's large eyes and optic lobes (of their brain) may be an adaptation for greater sensitivity to distant bioluminescence; signs of animals, such as prey aggregations or potential mates. This sensitivity is useful when monitoring a vast area of the [[water column]], which is largely featureless at these depths.<ref name="VisBrain"/>

===Antipredator behavior===
Like many deep-sea cephalopods, the vampire squid lacks [[Cephalopod ink|ink]] sacs. This, along with their low metabolic rate, lead to it adapting various alternate methods of defence. If disturbed, it will curl its arms up outwards and wrap them around its body, turning itself inside-out in a way, making itself seem larger and exposing the spiny projections on its tentacles (the cirri). The underside of the cape is heavily pigmented, concealing most of the body's photophores. The glowing arm tips are clustered together far above the animal's head, diverting attack away from critical areas. This [[Anti-predator adaptation|anti-predator behavior]] is dubbed the "pumpkin" or "pineapple" posture.<ref>{{cite web |url= https://www.youtube.com/watch?v=X8oWnbcLI40&t=33s |archive-url= https://ghostarchive.org/varchive/youtube/20211212/X8oWnbcLI40 |archive-date=2021-12-12 |url-status=live |title=What the vampire squid really eats|last=Monterey Bay Aquarium Research Institute (MBARI)|date=26 September 2012|via=YouTube}}{{cbignore}}</ref><ref>{{cite web |title = Vampire Squid Turns "Inside Out" |publisher = National Geographic |date=4 February 2010 |access-date = 3 June 2011 |url=https://www.nationalgeographic.com/science/article/100203-squid-vampire-threatened-video }}</ref> The armtips [[Regeneration (biology)|regenerate]], so if they are bitten off, they can serve as a diversion allowing the animal to escape while its predator is distracted.{{sfn|Robison |Reisenbichler |Hunt |Haddock |2003}}

If highly agitated, it may eject a sticky cloud of bioluminescent mucus containing innumerable orbs of blue light from its arm tips.<ref>{{cite web |title = Vampire Squid |publisher = Aquarium of the Pacific |access-date = 18 February 2025 |url=https://www.aquariumofpacific.org/onlinelearningcenter/species/vampire_squid }}</ref> 
<!-- {{Dubious|date=October 2024|reason=Is there a pore or similar structure on the arm tips that eject the mucus, instead of the siphon being used to blow it at threats (as in other cephalopods)?}} -->
This luminous barrage, which may last nearly 10 minutes, would presumably serve to dazzle would-be predators and allow the vampire squid to disappear into the dark without the need to swim far. The glowing "ink" is also able to stick to the predator, creating what is called the "burglar alarm effect" (making the vampire squid's would-be predator more visible to secondary predators, similar to the [[Atolla jellyfish|''Atolla'' jellyfish]]'s light display). The display is made only if the animal is very agitated, due to the metabolic cost of mucus regeneration.

Their aforementioned bioluminescent "fireworks" are combined with the writhing of glowing arms, along with erratic movements and escape trajectories, making it difficult for a predator to identify the squid itself among multiple sudden targets. The vampire squid's retractile filaments have been suggested to play a larger role in predator avoidance via both detection and escape mechanisms.<ref name=":2"/>

Despite these defence mechanisms, vampire squids have been found among the stomach contents of large [[Pelagic fish#Deep water fish|deepwater fish]], including [[giant grenadier]]s,<ref>{{cite journal |last1=Drazen |first1=Jeffrey C |last2=Buckley |first2=Troy W |last3=Hoff |first3=Gerald R |year=2001 |title=The feeding habits of slope dwelling macrourid fishes in the eastern North Pacific |journal=Deep-Sea Research Part I: Oceanographic Research Papers |volume=48 |issue=3 |pages=909–935 |doi=10.1016/S0967-0637(00)00058-3|bibcode=2001DSRI...48..909D }}</ref> and deep-diving mammals, such as [[whale]]s and [[sea lion]]s.

===Feeding===
Vampire squid have eight arms but lack feeding tentacles (like octopods), and instead use two retractile filaments in order to capture food. These filaments have small hairs on them, made up of many sensory cells, that help them detect and secure their prey. They combine waste with mucus secreted from the suckers to form balls of food. As [[Sedentary lifestyle|sedentary]] generalist feeders, they feed on [[marine snow|detritus]], including the remains of [[gelatinous zooplankton]] (such as [[salp]]s, [[larvacea]]ns, and medusae [[Jellyfish|jellies]]) and complete crustaceans, such as [[copepod]]s, [[ostracod]]s, [[Amphipoda|amphipod]]s, and [[Isopoda|isopod]]s,{{sfn|Hoving|Robison|2012}} as well as faecal pellets of other aquatic organisms that live above.<ref name=":0">{{cite web |first=Hannah |last=Krakauer |url=https://www.newscientist.com/article/dn22299-vampire-squid-from-hell-eats-faeces-to-survive-depths/ |website=[[New Scientist]] |date=26 September 2012 |title=Vampire squid from hell eats faeces to survive depths|access-date=7 May 2018}}</ref><ref>{{cite web|url=https://sta.uwi.edu/fst/lifesciences/sites/default/files/lifesciences/documents/ogatt/Vampyroteuthis_infernalis%20-%20Vampire%20Squid.pdf|title=''Vampyrotheuthis infernalis'' (Vampire Squid)|website=The Online Guide to the Animals of Trinidad and Tobago|publisher=[[University of the West Indies|UWI]]|access-date=24 May 2022}}</ref> Vampire squids also use a unique luring method where they purposefully agitate [[Bioluminescent bacteria|bioluminescent protist]]s in the water as a way to attract larger prey for them to consume.{{sfn|Hoving|Robison|2012}}

The mature vampire squid is also thought to be an opportunistic hunter of larger prey as fish bones and [[fish scale|scale]]s, along with gelatinous plankton, has been recorded in mature vampire squid stomachs.<ref name="Golikov 2019 19099">{{Cite journal |last=Golikov |first=A. V. |title=The first global deep-sea stable isotope assessment reveals the unique trophic ecology of Vampire Squid Vampyroteuthis infernalis (Cephalopoda) |journal=Nature |year=2019 |volume=9 |issue=1 |page=19099 |doi=10.1038/s41598-019-55719-1 |pmid=31836823 |pmc=6910912 |bibcode=2019NatSR...919099G}}</ref>

===Life cycle===
[[File:Vampyroteuthis1.jpg|thumb|Dissected adult (center) and two immature specimens]]
If hypotheses may be drawn from knowledge of other deep-sea cephalopods, the vampire squid likely reproduces slowly by way of a small number of large eggs, or a [[K-selected#K-selection|K-selected]] strategy. Ovulation is irregular and there is minimal energy devotion into the development of the gonad.<ref name=":3"/> Growth is slow, as nutrients are not abundant at depths frequented by the animals. The vastness of their habitat and its sparse population make reproductive encounters a fortuitous event. With [[Semelparity and iteroparity|iteroparity]] often seen in organisms with high adult survival rates, such as the vampire squid, many low-cost reproductive cycles would be expected for the species.{{sfn |Hoving |Laptikhovsky |Robison |2015}}

Reproduction of the vampire squid is unlike any other coleoid cephalopod; the males pass a "packet" of sperm to a female and the female accepts it and stores it in a special pouch inside her mantle. The female may store a male's hydraulically implanted [[spermatophore]] for long periods before she is ready to fertilize her eggs. Once she does, she may need to brood over them for up to 400 days before they hatch. Their reproductive strategy appears to be [[Semelparity and iteroparity|iteroparous]], which is an exception amongst the otherwise semelparous [[Coleoidea]].{{sfn |Hoving |Laptikhovsky |Robison |2015}} During their life, coleoid cephalopods are thought to go through only one reproductive cycle whereas vampire squid have shown evidence of multiple reproductive cycles. After releasing their eggs, new batches of eggs are formed after the female vampire squid returns to resting. This process may repeat up to, and sometimes more than, twenty times in their lifespan. These spawning events happen quite far apart due to the vampire squid's low metabolic rate.<ref name=":3">{{cite journal |last1=Henk-Jan |first1=Hoving |date=20 April 2015 |title=Vampire squid reproductive strategy is unique among coleoid cephalopods |journal= Current Biology |volume=25 |issue=8 |pages=R322–R323 |doi=10.1016/j.cub.2015.02.018 |pmid=25898098 |doi-access=free|bibcode=2015CBio...25.R322H }}</ref>

Few specifics are known regarding the [[ontogeny]] of the vampire squid. Hatchlings are about 8&nbsp;mm in length and are well-developed miniatures of the adults, with some differences: they are transparent, their arms lack webbing, their eyes are smaller proportionally, and their velar filaments are not fully formed.<ref name=":1">{{Cite journal |url=http://biostor.org/reference/74296 |title=Morphological Observations On A Hatchling And A Paralarva Of The Vampire Squid, Vampyroteuthis Infernalis Chun (Mollusca : Cephalopoda) |last=Young |first=R. E. |year=1998 |journal=Proceedings of the Biological Society of Washington |volume=112 |pages=661–666 |via=biostor.org |access-date=2020-02-09}}</ref> Their development progresses through three morphologic forms: the very young animals have a single pair of fins, an [[Paralarva|intermediate form]] has two pairs, and the mature form again has one pair of fins. At their earliest and intermediate phases of development, a pair of fins is located near the eyes; as the animal develops, this pair gradually disappears as the other pair develops.{{sfn|Pickford|1949}} As the animals grow and their surface area to volume ratio drops, the fins are resized and repositioned to maximize gait efficiency. Whereas the young propel themselves primarily by [[jet propulsion#Jet-propelled animals|jet propulsion]], mature adults prefer the more efficient means of flapping their fins.{{sfn|Seibel|Thuesen|Childress|1998}} This unique ontogeny caused confusion in the past, with the varying forms identified as several species in distinct families.{{sfn|Young|2002}}

The hatchlings survive on a generous internal [[yolk]] supply for an unknown period before they begin to actively feed.<ref name=":1"/> The younger animals frequent much deeper waters, feeding on marine snow and [[zooplankton]].<ref name="Golikov 2019 19099"/>

==Relationship with humans==
===Conservation status===
The vampire squid is currently not on any endangered or threatened species list and they have no known impact on humans.<ref>{{cite web |title=Vampire Squid |url=https://marinebio.org/species/vampire-squid/vampyroteuthis-infernalis/ |website=Marine Life |publisher=The MarineBio Conservation Society |access-date=5 March 2021}}</ref> Vampire squids are at increased risk for micro [[plastic pollution]] because their diet is mostly [[marine snow]].<ref>{{Cite journal |last1=Ferreira |first1=Guilherme |last2=Justino |first2=Anne |last3=Eduardo |first3=Leandro |last4=Lenoble |first4=Véronique |last5=Fauvelle |first5=Vincent |last6=Schmidt |first6=Natascha |last7=Vaske |first7=Teodoro |last8=Frédou |first8=Thierry |last9=Lucena-Frédou |first9=Flávia |date=January 2022 |title=Plastic in the inferno: Microplastic contamination in deep-sea cephalopods (Vampyroteuthis infernalis and Abralia veranyi) from the southwestern Atlantic |url=https://www.sciencedirect.com/science/article/abs/pii/S0025326X21013436 |journal=Marine Pollution Bulletin |volume=174|page=113309 |doi=10.1016/j.marpolbul.2021.113309 |pmid=35090293 |bibcode=2022MarPB.17413309F |s2cid=246387973 }}</ref> [[Microplastics|Micro plastics]] can cause death by decreasing feeding activity as they take up space in the digestive tract causing the animal's stomach to feel full without providing nutrients.<ref>{{Cite journal |last1=Zolotova |first1=Natalia |last2=Kosyreva |first2=Anna |last3=Dzhalilova |first3=Dzhuliia |last4=Fokichev |first4=Nikolai |last5=Makarova |first5=Olga |date=Jun 14, 2022 |title=Harmful effects of the microplastic pollution on animal health: a literature review |journal=PeerJ |volume=10 |pages=e13503 |doi=10.7717/peerj.13503 |pmid=35722253 |pmc=9205308 |doi-access=free }}</ref>

===Popular culture===
[[File:Pu - Vampyroteuthis infernalis - 2.jpg|thumb|Model vampire squid, [[Natural History Museum, London]]]]
Following an article in ''[[Rolling Stone]]'' magazine by [[Matt Taibbi]]<ref>{{Cite magazine|last=Taibbi|first=Matt|date=5 April 2010 |title=The Great American Bubble Machine|url=https://www.rollingstone.com/politics/politics-news/the-great-american-bubble-machine-195229/|access-date=25 February 2021|magazine=Rolling Stone|language=en-US}}</ref> after the [[subprime mortgage crisis]] of 2008, the term "vampire squid" has been regularly used in popular culture to refer to [[Goldman Sachs]], the American [[investment bank]].<ref>{{cite web|last=Zamansky|first=Jake|date=8 August 2013|website=Forbes|url=https://www.forbes.com/sites/jakezamansky/2013/08/08/the-great-vampire-squid-keeps-on-sucking/|title=The Great Vampire Squid Keeps On Sucking|access-date=25 February 2021|language=en-US}}</ref><ref>{{cite web|last=English|first=Simon|date=9 January 2020|website=The Evening Standard|url=https://www.standard.co.uk/business/goldman-sachs-the-death-of-the-vampire-squid-a4330326.html|title=Goldman Sachs: the death of the vampire squid|access-date=25 February 2021|language=en-GB}}</ref><ref>{{cite news|last=Blackhurst|first=Chris|date=7 February 2020|newspaper=[[The Independent]]|url=https://www.independent.co.uk/independentpremium/business/goldman-sachs-banking-giant-vampire-squid-2008-change-a9323191.html|title=Goldman Sachs is still the 'giant vampire squid': When will it decide to change?|access-date=25 February 2021|language=en-GB}}</ref>

Live vampire squids are shown in the "Ocean Deep" episode of ''[[Planet Earth (2006 TV series)|Planet Earth]]''.<ref>{{Cite web |title=BBC One - Planet Earth, Ocean Deep |url=https://www.bbc.co.uk/programmes/b0074t5y |access-date=2024-07-13 |website=BBC |language=en-GB}}</ref>

The [[Monterey Bay Aquarium]] (California, United States) became the first facility to put this species on display, in May 2014.<ref>{{cite news |work=[[KION-TV|KION News]] |date=1 May 2014 |title=World's first vampire squid on display at Monterey Bay Aquarium |url=https://kion546.com/news/2014/05/01/worlds-first-vampire-squid-on-display-at-monterey-bay-aquarium/ |access-date= 31 May 2014 }}</ref><ref>{{cite news |last=Adams |first=J. |date=5 May 2000 |title=First ever vampire squid goes on display at the Monterey Bay Aquarium |work=ReefBuilders |url=https://reefbuilders.com/2014/05/05/vampire-squid-display-monterey-bay-aquarium/ |access-date=31 May 2014 }}</ref>

Vampire Squids are a species that can be caught and cooked in the 2023 video game ''[[Dave the Diver]]''.<ref>{{Cite web |last=Barber |first=Bethany |date=2023-10-11 |title=Dave the Diver Fish List |url=https://progameguides.com/dave-the-diver/dave-the-diver-fish-list/ |access-date=2024-07-13 |website=Pro Game Guides |language=en}}</ref>

==Notes==
{{Reflist}}

==References==
{{Refbegin|30em}}
* {{cite web | year = 2003
 | last = Bolstad | first = Kat
 | url = http://www.tonmo.com/science/public/deepseacephs.php
 | title = Deep-Sea Cephalopods: An Introduction and Overview
}} (Version of 5/6/03, retrieved 2006-DEC-06.)
* {{cite book
 | last = Ellis
 | first = Richard
 | year = 1996
 | chapter = Introducing ''Vampyroteuthis infernalis'', the vampire squid from Hell
 | title = The Deep Atlantic: Life, Death, and Exploration in the Abyss
 | location = New York
 | isbn = 978-0-679-43324-8
 | access-date = 2007-04-30
 | url-access = registration
 | url = https://archive.org/details/deepatlanticlife00elli
 | publisher = New York : Alfred A. Knopf
 }}
* {{cite journal 
 | last1 = Fischer | first1 = Jean-Claude
 | last2 = Riou | first2 = Bernard
 | title = ''Vampyronassa rhodanica'' nov. gen. nov sp., vampyromorphe (Cephalopoda, Coleoidea) du Callovien inférieur de la Voulte-sur-Rhône (Ardèche, France)
 | journal = Annales de Paléontologie | year = 2002 | volume = 88 | issue = 1 | pages = 1–17
 | doi = 10.1016/S0753-3969(02)01037-6
| bibcode = 2002AnPal..88....1F
 }} (French with English abstract)
* {{cite journal |last1=Hoving |first1=Henk-Jan T. |last2=Robison |first2=Bruce H. |year=2012 |title=Vampire squid: Detritivores in the oxygen minimum zone |journal=Proceedings of the Royal Society B: Biological Sciences |volume=279 |issue=1747 |pages=4559–4567 |doi=10.1098/rspb.2012.1357 |pmid=23015627 |pmc=3479720}}
* {{cite journal |last1=Hoving |first1=Henk-Jan T. |last2=Laptikhovsky |first2=Vladimir V. |last3=Robison |first3=Bruce H. |title=Vampire squid reproductive strategy is unique among coleoid cephalopods |journal=Current Biology |date=20 April 2015 |volume=25 |issue=8 |pages=R322–R323 |url=http://oceanrep.geomar.de/28773/1/Hoving%2C%20Laptikhovsky%20and%20Robison%202015.pdf |access-date=29 July 2020 |doi=10.1016/j.cub.2015.02.018 |pmid=25898098 |s2cid=668950|doi-access=free |bibcode=2015CBio...25.R322H }}
* {{cite journal 
 | last = Pickford | first = Grace E.
 | title = ''Vampyroteuthis infernalis'' Chun an archaic dibranchiate cephalopod. II.
 | journal = External Anatomy | publisher = Dana Report | year = 1949 | issue = 32 | pages = 1–132}}
* {{cite journal 
 | last1 = Robison | first1 = Bruce H.
 | last2 = Reisenbichler | first2 = Kim R.
 | last3 = Hunt | first3 = James C.
 | last4 = Haddock | first4 = Steven H. D.
 | title = Light Production by the Arm Tips of the Deep-Sea Cephalopod ''Vampyroteuthis infernalis''
 | journal = Biological Bulletin | year = 2003 | volume = 205 | issue = 2 | pages = 102–109
 | url = http://www.biolbull.org/cgi/reprint/205/2/102.pdf | doi=10.2307/1543231
 |archive-url=https://web.archive.org/web/20110616191340/http://www.biolbull.org/cgi/reprint/205/2/102.pdf
 |archive-date=2011-06-16 |url-status=dead
 | pmid = 14583508 | jstor = 1543231 | s2cid = 16259043
 |issn=0006-3185}}
* {{cite web 
 | last = Seibel | first = Brad A.
 | url = http://www.nhm.ac.uk/hosted_sites/tcp/vampy.html
 | archive-url = https://web.archive.org/web/20051224235910/http://www.nhm.ac.uk/hosted_sites/tcp/vampy.html
 | archive-date = 2005-12-24
 | title = Vampyroteuthis infernalis
 | year = 2001 | access-date = 2006-12-06
}}
* {{cite journal 
 | last1 = Seibel | first1 = Brad A.
 | last2 = Thuesen | first2 = Erik V.
 | last3 = Childress | first3 = James J.
 | title = Flight of the vampire: ontogenetic gait-transition in ''Vampyroteuthis infernalis'' (Cephalopoda: Vampyromorpha)
 | journal = Journal of Experimental Biology | year = 1998 | volume = 201 | pages = 2413–2424
 | url = http://jeb.biologists.org/cgi/reprint/201/16/2413.pdf | issue=16 | doi = 10.1242/jeb.201.16.2413
 | pmid = 9679103 }}
* {{cite journal 
 | last1 = Seibel | first1 = Brad A.
 | last2 = Chausson | first2 = Fabienne
 | last3 = Lallier | first3 = Francois H.
 | last4 = Zal | first4 = Franck
 | last5 = Childress | first5 = James J.
 | title = Vampire blood: respiratory physiology of the vampire squid (Cephalopoda: Vampyromorpha) in relation to the oxygen minimum layer
 | journal = Experimental Biology Online | year = 1999 | volume = 4 | issue = 1 | pages = 1–10
 | doi = 10.1007/s00898-999-0001-2
| bibcode = 1999EvBO....4a...1S
 | s2cid = 85327502 }} (HTML abstract)
*{{cite journal |doi=10.1111/j.1469-7998.1976.tb04704.x |title=The statocyst of Vampyroteuthis infernalis (Mollusca: Cephalopoda) |journal=Journal of Zoology |volume=180 |issue=4 |pages=565–588 |year=2009 |last1=Stephens |first1=P. R. |last2=Young |first2=J. Z. }}
* {{cite web 
 | last = Young | first = Richard E.
 | url = http://tolweb.org/accessory/Vampyroteuthidae_Taxa?acc_id=2420
 | title = Taxa Associated with the Family Vampyroteuthidae
 | date = June 2002 | access-date = 2006-12-06
}}
{{Refend}}

==External links==
{{Commons}}
*{{CephBase Species|703}}
*[[Tree of Life Web Project|Tree of Life]]: [http://tolweb.org/Vampyroteuthis_infernalis ''Vampyroteuthis infernalis''].
*[https://web.archive.org/web/20070819074113/http://educatedearth.net/video.php?id=3061 National Geographic video of a vampire squid]
*[https://web.archive.org/web/20121216222810/http://www.mbari.org/news/news_releases/2012/vampfood/vampfood-release.html Monterey Bay Aquarium Research Institute (MBARI): What the vampire squid really eats.]
*[http://deepseacreatures.org/vampire-squid Vampire squid]
* ''Vampyroteuthis infernalis'' discussed on [[Radio New Zealand|RNZ]] ''[[Critter of the Week]]'', [https://www.rnz.co.nz/national/programmes/afternoons/collections/critter-of-the-week/audio/2018911020/critter-of-the-week-vampire-squid 13 Oct 2023]
*[http://tolweb.org/accessory/Vampyroteuthis_infernalis_Photophores?acc_id=1764 The vampire squid's photophores and photoreceptors]
*[http://tolweb.org/accessory/Vampyroteuthis_Hatchling?acc_id=1767 Diagram and images of a ''Vampyroteuthis'' hatchling]
*[http://www.biolbull.org/cgi/content/full/205/2/102/F6 Photomicrograph of arm tip fluorescence]

{{Taxonbar|from=Q2509902}}
{{Authority control}}

[[Category:Squid]]
[[Category:Cephalopods described in 1903]]
[[Category:Bioluminescent molluscs]]
[[Category:Taxa named by Carl Chun]]