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What the sources say

Dumbo OctopusGrimpoteuthis

Every figure, record and mechanism on the Dumbo Octopus profile was written from a source, and this is the working table behind it: 51 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.

Profile updated

Source
01

Oceana, Marine Life Encyclopedia

Dumbo Octopus. Oceana, Marine Life Encyclopedia.

The page saysamong the deepest-living of all known octopuses
The source saysamong the deepest-living of all known octopus speciesNote: final pass restored 'known', which the tagline had dropped
The page saysfrom about 100 to 7,000 meters (328 to 22,965 feet) down
The source saysranging from depths of 100 to 7,000 meters (328 to 22,965 feet)
The page saysThe deep seafloor worldwide
The source saysThey live in the deep sea around the world
The page saysIt also swims with its ear-like fins, unusual for octopuses, which typically rely on jet propulsion.
The source saysan unusual means of travel for octopuses, which typically rely on jet propulsion to move
The page saysThey are among the deepest-living of all known octopuses.
The source saysamong the deepest-living of all known octopus species
The page saysThe genus Grimpoteuthis ranges from about 100 to 7,000 meters (328 to 22,965 feet) down
The source saysranging from depths of 100 to 7,000 meters (328 to 22,965 feet)
The page saysOctopuses typically rely on jet propulsion to move.
The source saysoctopuses, which typically rely on jet propulsion to moveNote: FAQ3's declared ref is aop-dumbo; the following claims (from aop-dumbo) back the rest of this FAQ's answer
The page saysit may be vulnerable to sharks, fur seals, fish, and sperm whales
The source saysThey may be vulnerable to a number of predators, including sharks, fur seals, fish, and sperm whales.
The page saysnot one species but a whole genus of deep-sea octopuses
The source saysThe name “dumbo octopus” does not refer to one species, but ratherNote: the page's own count (18) conflicts with aop-dumbo's 'about 17' and boem-dumbo's '17 known species', so the page states no count at all
The page saysAmong all known octopuses, they are some of the deepest-living.
The source saysamong the deepest-living of all known octopus species
The page saysDumbo octopuses are rarely seen
The source sayshese octopuses are rarely seen
The page sayssome species are known only from a single recorded observation
The source sayssome dumbo octopus species are known only from a single recorded observation
The page saysinstead of jetting, as octopuses typically do
The source saysan unusual means of travel for octopuses, which typically rely on jet propulsion to moveNote: vibe.reason (task #506)

Source
02

Bureau of Ocean Energy Management, U.S. Department of the Interior 2024

Dumbo Octopus: The Whimsical Survivor of the Deep. Bureau of Ocean Energy Management, U.S. Department of the Interior, 2024.

The page sayswebbed umbrella arms
The source sayswhich are a kind of umbrella octopus, characterized by a web of skin in between their arms
The page saysNo ink sac: it moves quickly to get away instead
The source saysThe Dumbo octopus lacks an ink sac that other octopus use as a defense mechanism, so it uses its ability to change color and move quickly to avoid predators.Note: the source also credits colour change; that ability is contradicted by oceana-dumbo ('dumbo octopuses do not have an ink sac and cannot change'), so the page claims only the fast getaway
The page saysMost dumbo octopuses average 20 to 30 centimeters (7.9 to 12 inches) in length.
The source saysMost Dumbo octopus average between 20-30 cm (7.9-12 inches) in length
The page saysThe largest found was much bigger: 1.8 meters (about 6 feet) long and 5.9 kilograms (13 pounds).
The source saysthe largest found was 1.8m (6 foot 32 inches) long and weighed 5.9 kg (13 lbs)Note: source's own imperial figure ('6 foot 32 inches') looks like a scraping artifact; '1.8 meters (about 6 feet)' is used instead of quoting it verbatim. 'The largest found' keeps the source's framing: this is the record individual, not a typical size
The page saysflapping the pair of ear-like fins just above its eyes
The source saysa pair of ear-like fins that protrude just above its eyes ... the octopus flaps these fins to propel itself about the ocean floor
The page saysNo, it has no ink sac, the defense other octopuses use. Instead, when something threatens it, a dumbo octopus moves quickly to get away, and there are few predators for Grimpoteuthis in the deep ocean anyway
The source saysThe Dumbo octopus lacks an ink sac that other octopus use as a defense mechanism, so it uses its ability to change color and move quickly to avoid predators. Fortunately, there are few predators for Grimpoteuthis in the deep ocean.
The page saysnamed for a pair of ear-like fins that stick out just above their eyes and flap like the cartoon elephant's, propelling them around the ocean floor
The source saysThe Dumbo octopus gets its name due to a pair of ear-like fins that protrude just above its eyes. Just like the cartoon elephant, the octopus flaps these fins to propel itself about the ocean floor.
The page saysacross the world's oceans
The source saysin oceans all around the world
The page saysThe largest found was far bigger: 1.8 meters (about 6 feet) and 5.9 kilograms (13 pounds).
The source saysthe largest found was 1.8m (6 foot 32 inches) long and weighed 5.9 kg (13 lbs)Note: same source as FAQ2's version of this claim; imperial length rounded from the source's garbled '6 foot 32 inches'
The page saysA dumbo octopus has no proper beak, just an underdeveloped mouth opening
The source saysThe mouth of Dumbo octopus is an underdeveloped or nonexistent beak.
The page saysinstead of tearing food apart it pounces on isopods, amphipods, copepods, and bristle worms and swallows them whole
The source saysThe mouth of Dumbo octopus is an underdeveloped or nonexistent beak. This allows them to pounce on prey and swallow them whole.Note: the sentence's 'so' is the source's own causal link ('This allows them to'); aop-dumbo states the same mechanism ('a degenerated radula-type opening that allows it to swallow prey whole instead of having to tear and grind it')
The page saysIt also has no ink sac, the defense other octopuses use. Instead, when something threatens it, a dumbo octopus moves quickly to get away, and there are few predators for it in the deep ocean anyway
The source saysThe Dumbo octopus lacks an ink sac that other octopus use as a defense mechanism, so it uses its ability to change color and move quickly to avoid predators. Fortunately, there are few predators for Grimpoteuthis in the deep ocean.
The page saysBlue blood carries oxygen better down here.
The source saysGrimpoteuthis have blue blood because of their blood’s high copper content. Blood with high copper content is more efficient at transporting oxygen in the low-temperature, oxygen-depleted waters of the deep ocean.
The page saysA dumbo octopus's blood is blue because of a high copper content, and blood with a high copper content is more efficient at carrying oxygen through the cold, low-oxygen water of the deep sea.
The source saysGrimpoteuthis have blue blood because of their blood’s high copper content. Blood with high copper content is more efficient at transporting oxygen in the low-temperature, oxygen-depleted waters of the deep ocean.
The page saysDumbo octopuses are solitary, so they have to make the most of any meeting with the opposite sex.
The source saysDumbo octopus are solitary creatures, so they must make the most of any encounters they have with the opposite sex
The page sayswhenever the chance arises
The source sayslay the eggs under small rocks or shells when the opportunity arises
The page saysswims by flapping its ear-like fins
The source saysa pair of ear-like fins that protrude just above its eyes ... the octopus flaps these fins to propel itself about the ocean floorNote: vibe.reason (task #506); replaces 'peaceful weightless drifting through deep midnight water', a place and a mood

Source
03

Aquarium of the Pacific, Online Learning Center

Dumbo Octopus. Aquarium of the Pacific, Online Learning Center.

The page sayssome living as deep as 7,000 meters (23,000 feet)
The source sayswith some living as deep as 7,000 m (23000 ft) below sea level
The page saystypically between 3,000 and 4,000 meters
The source saysat depths of depths of 3000 to 4000 m (9800 to 13000 ft)
The page saysIsopods, amphipods, copepods, and bristle worms, pounced on and swallowed whole
The source saysDumbo octopuses pounce on prey and eat it whole. Their diet includes copepods, isopods, bristle worms, and amphipods.
The page saystypically staying in a narrower band between 3,000 and 4,000 meters
The source saysat depths of depths of 3000 to 4000 m (9800 to 13000 ft)
The page saysto move with grace and ease
The source saysFlapping their Dumbo ear-like fins gets them moving with peculiar grace and ease.
The page saysFor a sudden thrust, useful for escaping a predator, it expands and contracts the webbing between its arms or shoots water through its funnel.
The source saysExpanding and contracting the webbing between their tentacles or by shooting water through their funnel cause a sudden thrust, useful for escaping a predator.Note: final pass: the source gives the web pulse and the funnel jet as the sudden thrust, and the fins as the graceful movement; 'slow' was in no source
The page saysThey live on the bottom, or hovering just above it
The source sayslive on the bottom, or hovering just slightly above the seafloor
The page saysA dumbo octopus flies instead, flapping those big fins to move with grace and ease.
The source saysFlapping their Dumbo ear-like fins gets them moving with peculiar grace and ease.
The page saysit pounces on isopods, amphipods, copepods, and bristle worms and swallows them whole
The source saysDumbo octopuses pounce on prey and eat it whole. Their diet includes copepods, isopods, bristle worms, and amphipods.
The page saysMuch of that food drifts by in ocean currents or collects around deep-sea vents.
The source saysMuch of the food they consume is also found around ocean vent ecosystems or floating along in the current.
The page saysDissected females have shown eggs in various stages of maturation, meaning there is no breeding season
The source saysFemales necropsied have shown eggs in various stages of maturation which means that there is no breeding seasonNote: 'necropsied' (examined post-mortem) simplified to 'dissected' for the audience
The page saysa female can lay eggs continuously under rocks or shells
The source saysfemales can lay eggs continuously under small rocks or on shells in the deep ocean
The page saysA male delivers a sperm packet with a special bump on one arm, and it is thought the female can use the sperm to fertilize eggs at almost any time.
The source saysMales have a separate protuberance on one of their arms that transports an encapsulated sperm packet into the female’s mantle. It is thought the female can utilize sperm for fertilization at almost any time.

Source
04

Ziegler & Sagorny 2021

Ziegler & Sagorny (2021). Holistic description of new deep sea megafauna (Cephalopoda: Cirrata) using a minimally invasive approach. BMC Biology.

The page saysa study described a new species, Grimpoteuthis imperator, from a dead specimen collected in the North Pacific with a chain bag dredge
The source saysThe single cirrate specimen was collected in the North Pacific Ocean during scientific cruise SO-249 BERING (R/V SONNE) using a chain bag dredgeNote: '2021' in the sentence is the paper's own publication year, carried by the reference; 'The animal arrived dead on deck' (next sentence) backs 'a dead specimen'
The page saysa dead specimen
The source saysThe animal arrived dead on deck
The page saysat a site in the Emperor Seamounts 3,913 to 4,417 meters deep
The source saysEmperor Seamounts, North Pacific Ocean; 48° 27.53′ N, 168° 52.21′ E, 3913–4417 m depthNote: quote is part of the paper's Type locality sentence; the source uses a thin space (U+2009) between the number and unit
The page saysthe researchers combined MRI and CT scans with DNA barcoding
The source sayshigh-field magnetic resonance imaging, micro-computed tomography, and DNA barcoding were combined
The page saysa minimally invasive approach chosen to avoid potentially harmful effects on the unique specimen
The source saysPotentially harmful effects on this unique deep-sea cephalopod specimen were avoided by scanning the fixed animal without admixture of a contrast agentNote: 'minimally invasive' is the paper's own description of its method (title and abstract); the scope is the single G. imperator holotype, not the genus

Source
05

Shea et al. 2018

Shea et al. (2018). Dumbo octopod hatchling provides insight into early cirrate life cycle. Current Biology.

The page saysthe first living hatchling to be filmed already had everything it needed to swim by flapping its fins and to capture prey
The source saysHere, we provide the first video of a living hatchling ... The specimen's behavior and advanced state of organ development show that cirrate hatchlings possess all morphological features required for movement via fin-swimming, for visually and chemically sensing their environment, and for prey capture
The page saysDumbo octopuses hatch as competent juveniles, able to fend for themselves straight away.
The source saysThese data provide evidence that dumbo octopods hatch as competent juveniles.Note: the source's 'dumbo octopods' is written as 'dumbo octopuses' for the audience; 'able to fend for themselves straight away' explains 'competent juveniles' and adds no fact the quote does not carry

Source
06

Jamieson & Vecchione 2020

Jamieson & Vecchione (2020). First in situ observation of Cephalopoda at hadal depths (Octopoda: Opisthoteuthidae: Grimpoteuthis sp.). Marine Biology.

The page saysA 2020 study reported a Grimpoteuthis filmed by a video lander at 6,957 meters in the Indian Ocean, extending the known maximum depth range for cephalopods by 1,812 meters.
The source saysThe demersal cirrate octopod Grimpoteuthis sp. was observed at both 5760 and 6957 m in the Indian Ocean. These observations extend the known maximum depth range for cephalopods by 1812 mNote: hand check: Springer refuses the full text, so the quote is the Crossref/Europe PMC abstract read via `audit:sources --abstract` and verify:quotes cannot confirm it automatically. Confirmed word for word on 2026-09-17, including 'by HD video lander' earlier in the abstract. '2020' is the paper's own publication year. The extension is to the depth range for cephalopods, not for octopuses or for this genus.

How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.