''Taningia danae'', the Dana octopus squid, is a species of

squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...

in the family

Octopoteuthidae The Octopoteuthidae are a family of squid comprising two genera. The family is characterized by tentacles which cease to grow after the paralarval stage, and the use of a penis, instead of a hectocotylus A hectocotylus (plural: ''hectocotyli' ...

. It is one of the largest known squid species, reaching a mantle length of and total length of . The largest known specimen, a mature female, weighed .Roper, C.F.E. & P. Jereb 2010. Family Octopoteuthidae. In: P. Jereb & C.F.E. Roper (eds.)
Cephalopods of the world. An annotated and illustrated catalogue of species known to date. Volume 2. Myopsid and Oegopsid Squids
'. FAO Species Catalogue for Fishery Purposes No. 4, Vol. 2. FAO, Rome. pp. 262–268. ''Taningia danae'' is named after

Danish Danish may refer to: * Something of, from, or related to the country of Denmark People * A national or citizen of Denmark, also called a "Dane," see Demographics of Denmark * Culture of Denmark * Danish people or Danes, people with a Danish a ...

fisheries biologist

Åge Vedel Tåning Åge Vedel Tåning (27 July 1890 – 26 September 1958 in Copenhagen) was a Danish ichthyologist. He was a director of the Carlsberg Laboratory, the Dana collection and the Danish Fisheries Research Station. Lanternfish genus '' Taaningichthys'' ...

(1890–1958), who often traveled on the research vessel '' Dana''.

Ecology

''Taningia danae'' possesses bioluminescence, like other octopoteuthids. Its

photophores A photophore is a glandular organ that appears as luminous spots on various marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors, ...

are some of the largest such organs known to science, the organs being compared in size to

fists A fist is the shape of a hand when the fingers are bent inward against the palm and held there tightly. To make or clench a fist is to fold the fingers tightly into the center of the palm and then to clamp the thumb over the middle phalanges; in ...

lemons The lemon (''Citrus limon'') is a species of small evergreen trees in the flowering plant family Rutaceae, native to Asia, primarily Northeast India (Assam), Northern Myanmar or China. The tree's ellipsoidal yellow fruit is used for culina ...

. They possess a black membrane over the photophore that may conceal the organs, allowing the squid to blink its lights; this membrane has been compared to

eyelids An eyelid is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. The human eye ...

as a result. In 2005, a

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

ese research team headed by

Tsunemi Kubodera is a Japanese zoologist with the National Museum of Nature and Science. On September 30, 2004, Kubodera and his team became the first people to ''photograph'' a live giant squid in its natural habitat.Kubodera, T. & K. Mori 2005First-ever observa ...

managed to film ''T. danae'' in its natural habitat for the first time. The video footage, shot in deep water off

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in the northern

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

, shows ''T. danae'' emitting blinding flashes of light from

photophore A photophore is a glandular organ that appears as luminous spots on various marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors, ...

s on its

arm In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint (shoulder joint) and the elbow joint. The distal part of the upper limb between th ...

s as it attacks its prey. It is believed that this highly maneuverable squid uses the bright flashes to disorient potential prey. These flashes may also serve to illuminate the prey to make for easier capture as well as a

courtship Courtship is the period wherein some couples get to know each other prior to a possible marriage. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marriage. A courtship may be an informal and private m ...

and territorial display.Kubodera, T., Y. Koyama & K. Mori 2006. ''Proceedings of the Royal Society B: Biological Sciences'' 274(1613): 1029–1034. As well as a predatorial characteristic, ''T. danae'' bioluminescence has also been suggested to be a defense mechanism. Juveniles of this species have been observed moving rapidly in the direction of potential predators, as if hunting, to disorient and startle the threat with a mock attack. In 2012, ''T. danae'' was filmed twice more during a search for the

giant squid The giant squid (''Architeuthis dux'') is a species of deep-ocean dwelling squid in the family Architeuthidae. It can grow to a tremendous size, offering an example of abyssal gigantism: recent estimates put the maximum size at around Trace ...

for the

Discovery Channel Discovery Channel (known as The Discovery Channel from 1985 to 1995, and often referred to as simply Discovery) is an American cable channel owned by Warner Bros. Discovery, a publicly traded company run by CEO David Zaslav. , Discovery Channe ...

Special, ''Monster Squid: The Giant Is Real''. Remains of ''T. danae'' have, on occasion, been found washed ashore on beaches. In 2008, a mantle of ''T. danae'' was discovered by students in

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's Grape Bay, while

tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

remnants were found farther along the shore. In early 2013, a specimen with a length (excluding arms) of was trawled at a depth of off the coast of Estaca de Bares, Galicia,

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. It was loaned to the Spanish Institute of Oceanography. ¹⁵N ratios showed that this squid is a top predator.Guerreiro, Miguel & Phillips, Richard A & Cherel, Yves & Ceia, Filipe R & Alvito, Pedro & Rosa, Rui & Xavier, José C. 2015. Habitat and trophic ecology of Southern Ocean cephalopods from stable isotope analyses. ''Marine Ecology Progress Series'', published online on June 18, 2015. In turn, they are eaten by the

sperm whale The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus ''Physeter'' and one of three extant species in the sperm whale famil ...

Notes

:a.This is the weight of a specimen from the North Atlantic measuring in mantle length. The previously reported maximum weight of for ''T. danae'' (based on this same specimen) stems from a typographical error in the original paperRoper, C.F.E. & M. Vecchione 1993. In: T. Okutani, R.K. O'Dor & T. Kubodera (eds.) ''Recent Advances in Cephalopod Fisheries Biology''. Tokai University Press, Tokyo. pp. 441–456. of Roper & Vecchione (1993).

References

External links

Tree of Life web project: ''Taningia danae''BBC: Large squid lights up for attack

Ecology

Notes

References

Further reading

External links

See also