---
title: "What the sources say about the Gulper Eel (Pelican Eel) | AnimalTracks.wiki"
description: "47 claims from the Gulper Eel (Pelican Eel) profile, each beside the words of the source that backs it."
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# What the sources say about the Gulper Eel (Pelican Eel) (*Eurypharynx pelecanoides*)

> 47 claims from the Gulper Eel (Pelican Eel) profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Gulper Eel (Pelican Eel)](https://animaltracks.wiki/animals/gulper-eel/)

## Eurypharynx pelecanoides. FishBase.

https://www.fishbase.se/summary/Eurypharynx-pelecanoides.html

| The page says | The source says |
| :--- | :--- |
| a glowing tail tip | Tail attenuated and ending in an expanded, luminous caudal organ. |
| Tropical and temperate oceans worldwide | Circumglobal: In tropical to temperate waters. |
| from about 500 to 7,625 meters deep and usually around 1,200 to 1,400 meters | depth range 500 - 7625 m (Ref. 58426 ), usually 1200 - 1400 m (Ref. 559 ) |
| Mainly crustaceans, plus fish, squid and their relatives, and other invertebrates | Adults feed mainly on crustaceans, but also take fishes, cephalopods, and other invertebrates (note: 'Squid and their relatives' renders 'cephalopods' for a young reader.) |
| has a mouth greatly enlarged by jaws that extend backward | Mouth greatly enlarged by a backward extension of jaws, gape comprising half or more of preanal length; buccal cavity greatly distensible. |
| Its gape is half or more of the length from its snout to its vent | Mouth greatly enlarged by a backward extension of jaws, gape comprising half or more of preanal length; buccal cavity greatly distensible. (note: FishBase's 'preanal length' is snout to anus (vent); 'its rear opening' defines the vent for a young reader.) |
| the inside of its mouth can stretch enormously | Mouth greatly enlarged by a backward extension of jaws, gape comprising half or more of preanal length; buccal cavity greatly distensible. (note: 'Buccal cavity greatly distensible' rendered for a young reader.) |
| Gulper eels live in tropical and temperate oceans worldwide | Circumglobal: In tropical to temperate waters. |
| between about 500 and 7,625 meters down, though they usually stay around 1,200 to 1,400 meters | depth range 500 - 7625 m (Ref. 58426 ), usually 1200 - 1400 m (Ref. 559 ) |
| In the eastern Pacific they range from northern California to Peru | Eastern Pacific: ranges from northern California to Peru. |
| Instead of pores, the gulper eel's lateral line has groups of raised tubes | lateral line without pores, instead with groups of elevated tubules |
| Its eggs hatch into drifting larvae called leptocephali | Oviparous, planktonic eggs hatch into planktonic leptocephalus larvae |
| It can grow to 1 meter long, though 55 centimeters is a more common length | Max length : 100.0 cm TL male/unsexed; (Ref. 27000 ); common length : 55.0 cm NG male/unsexed; (Ref. 5755 ) (note: 100 cm is 1 meter.) |
| it is of no interest to fisheries | Human uses
Fisheries: of no interest |
| They have been recorded from about 500 to 7,625 meters down, though they usually stay around 1,200 to 1,400 meters | depth range 500 - 7625 m (Ref. 58426 ), usually 1200 - 1400 m (Ref. 559 ) |
| Gulper eels live across the world's tropical and temperate oceans, and in the eastern Pacific they range from northern California to Peru | Circumglobal: In tropical to temperate waters. Eastern Pacific: ranges from northern California to Peru. |
| Its tapering tail ends in an expanded organ that gives off light | Tail attenuated and ending in an expanded, luminous caudal organ. |
| The IUCN assessed it as Least Concern in 2012 | Least Concern (LC) ; Date assessed: 24 May 2012 (note: FishBase's IUCN field (Red List version 2025-2) shows the 2012 assessment is still the current one.) |
| it is of no interest to fisheries | Human uses
Fisheries: of no interest |
| dangerLevel: Low | Threat to humans Harmless |

## Nielsen, Bertelsen & Jespersen (1989). The Biology of Eurypharynx pelecanoides (Pisces, Eurypharyngidae). Acta Zoologica.

https://doi.org/10.1111/j.1463-6395.1989.tb01069.x

| The page says | The source says |
| :--- | :--- |
| A huge gape | The huge gape is unsuitable for suction feeding. |
| probably engulfed by a forward thrust of the head | It is proposed that prey engulfing is accomplished by a forward thrust of the head by which the produced water pressure will expand the buccal cavity to a volume several times that of the fish itself. (note: 'Probably' carries the source's 'It is proposed'.) |
| researchers propose can expand to several times the eel's own body volume | It is proposed that prey engulfing is accomplished by a forward thrust of the head by which the produced water pressure will expand the buccal cavity to a volume several times that of the fish itself. |
| A 1989 study of 760 Atlantic specimens | This paper is based on 760 Atlantic specimens of pelican eels caught from off Iceland to 48°S in depths between 2750 and c. 500 m. (note: 1989 is the reference's publication year.) |
| judged that huge gape unsuitable for sucking prey in | The huge gape is unsuitable for suction feeding. |
| the researchers proposed, the eel thrusts its head forward, and the water pressure this creates expands its mouth to several times the volume of the eel itself | It is proposed that prey engulfing is accomplished by a forward thrust of the head by which the produced water pressure will expand the buccal cavity to a volume several times that of the fish itself. |
| In the 1989 study, stomachs from 120 eels held a varied diet led by crustaceans, fish and squid | Stomach contents from 120 specimens show a varied diet dominated by crustaceans, fish and squid. (note: 1989 is the reference's publication year.) |
| often Sargasso weed too, which the researchers took as a sign that the eel does not pick and choose what it swallows | The frequent occurrence of Sargasso weed consumed by Eurypharynx indicates a lack of prey-item discrimination. |
| Its forward-facing eyes appear to give it depth vision for locating prey, possibly helped by its well developed lateral line | The forward directed eyes appear to enable stereoscopic prey localization, possibly aided by the well developed lateral line. (note: 'Depth vision for locating prey' renders 'stereoscopic prey localization'. The lateral line definition is general knowledge.) |
| In the 1989 study, ripening fish, males especially, changed in some body features, a sign of that single breeding | When ripening, males especially show morphological changes in some characters, indicating that the pelican eel breeds only once (note: 1989 is the reference's publication year.) |
| Breeding only once seems to be the rule among eels in general | a condition which seems to be the rule among eels |
| Not by sucking it in | The huge gape is unsuitable for suction feeding. |
| a 1989 study of 760 Atlantic specimens judged the huge gape unsuitable for that | This paper is based on 760 Atlantic specimens of pelican eels caught from off Iceland to 48°S in depths between 2750 and c. 500 m. (note: 1989 is the reference's publication year; the verdict is the abstract's 'The huge gape is unsuitable for suction feeding.') |
| The researchers proposed that the eel thrusts its head forward instead, and the water pressure this creates expands its mouth to several times the volume of the eel itself | It is proposed that prey engulfing is accomplished by a forward thrust of the head by which the produced water pressure will expand the buccal cavity to a volume several times that of the fish itself. |

## Kim et al. (2019). Bioinspired dual-morphing stretchable origami. Science Robotics.

https://doi.org/10.1126/scirobotics.aay3493

| The page says | The source says |
| :--- | :--- |
| a mouth that first unfolds and then inflates | which first unfolds and then inflates its mouth to maximize the probability of engulfing the prey |
| A mouth that first unfolds and then inflates | which first unfolds and then inflates its mouth to maximize the probability of engulfing the prey |
| Robot designers have copied that mouth | we built an artificial creature mimicking a pelican eel and reproduced biomimetic dual-morphing behavior |
| Their 2019 paper describes it changing shape in two steps: it first unfolds and then inflates, to give the eel the best chance of engulfing its prey | the "dual-mode" morphing of Eurypharynx pelecanoides (commonly known as the pelican eel), which first unfolds and then inflates its mouth to maximize the probability of engulfing the prey (note: 2019 is the reference's publication year (Science Robotics).) |
| Their design uses stretchable origami units that imitate the pelican eel's stretchable, foldable frames | a set of entirely stretchable origami units that imitate the morphing principle of the pelican eel's stretchable and foldable frames |
| the team built an artificial pelican eel that reproduced the same two-step move | we built an artificial creature mimicking a pelican eel and reproduced biomimetic dual-morphing behavior |
| a mouth that first unfolds, then inflates to engulf its prey | which first unfolds and then inflates its mouth to maximize the probability of engulfing the prey |

## Poulsen et al. (2018). Resolving deep-sea pelagic saccopharyngiform eel mysteries: Identification of Neocyema and Monognathidae leptocephali and establishment of a new fish family "Neocyematidae" based on larvae, adults and mitogenomic gene orders. PLOS ONE.

https://doi.org/10.1371/journal.pone.0199982

| The page says | The source says |
| :--- | :--- |
| One Shot Only | All of the saccopharyngiforms are one-time spawners |
| Gulper eels and the related deep-sea eels in their group all spawn just once in their lives | All of the saccopharyngiforms are one-time spawners |
| Most vertebrates arrange the genes in their mitochondria, the energy-producing parts of cells, in the same order | The vast majority of vertebrates show a particular mitochondrial gene order (note: The mitochondria definition is general knowledge.) |
| a 2018 study found that the gulper eel's family and four related deep-sea eel families each have an order of their own | all five families show unique gene orders (note: The five families are Cyematidae, Eurypharyngidae, Monognathidae, Saccopharyngidae and the new Neocyematidae; 2018 is the reference's year.) |
| Researchers conclude that the species spawns in the Sargasso Sea, where its larvae are often caught, small ones included | It is frequently collected as leptocephali in the Sargasso Sea where it spawns based on the presence of small larvae. |

## Iwamoto (2015). Eurypharynx pelecanoides. The IUCN Red List of Threatened Species 2015: e.T18227119A42691734.

https://doi.org/10.2305/iucn.uk.2015-4.rlts.t18227119a42691734.en

| The page says | The source says |
| :--- | :--- |
| The IUCN rates it Least Concern | IUCN Red List category: Least Concern (LC). |