Cephalopod size

[10] Tales of giant squid have been common among mariners since ancient times, and may have inspired the monstrous kraken of Nordic legend, said to be as large as an island and capable of engulfing and sinking any ship.

In squids, total length is inclusive of the feeding tentacles, which in some species may be longer than the mantle, head, and arms combined (chiroteuthids such as Asperoteuthis acanthoderma being a prime example).

It can also vary widely depending on the state of the specimen at the time of weighing (for example, whether it was measured live or dead, wet or dry, frozen or thawed, pre- or post-fixation, with or without egg mass, and so on).

[2] The smallest adult size among living cephalopods is attained by the so-called pygmy squids, Idiosepius,[32] and certain diminutive species of the genus Octopus, both of which weigh less than 1 gram (0.035 oz) at maturity.

Cephalopods of comparable size to the largest present day squid are known from fossil remains, including enormous examples of ammonoids, belemnoids, nautiloids, orthoceratoids, teuthids, and vampyromorphids.

[43] Though a substantial number of colossal squid (Mesonychoteuthis hamiltoni) remains have been recorded (Xavier et al., 1999 collated 188 geographical positions for whole or partial specimens caught by commercial and scientific fisheries), very few adult or subadult animals have ever been documented, making it difficult to estimate the maximum size of the species.

[89] Teichert & Kummel (1960:6) suggested an even larger original shell diameter of around 3.5 m (11 ft) for this specimen, assuming the body chamber extended for three-fourths to one full whorl.

[108] Reports of giant squid (Architeuthis dux) specimens reaching or even exceeding 18 m (59 ft) in total length are widespread, but no animals approaching this size have been scientifically documented in recent times.

[53] It is now thought likely that such lengths were achieved by great lengthening of the two long feeding tentacles, analogous to stretching elastic bands, or resulted from inadequate measurement methods such as pacing.

[57] On the subject of the oft-cited maximum size of 18 metres—or 60 feet—Dery (2013) quoted giant squid experts Steve O'Shea and Clyde Roper: If this figure [45 ft or 14 m] seems a little short of the Brobdingnagian claims made for Architeuthis in most pop-science stories about the animal, that's probably because virtually every general-interest article dutifully repeats the magic number of 60 feet.

I have examined specimens in museums and laboratories around the world—perhaps a 100 or so—and I believe the 60-foot number comes from fear, fantasy, and pulling the highly elastic tentacles out to the near breaking point when they are measured on the shore or on deck.

[nb 8] Paxton added: "A 4.5 m [15 ft] specimen from Mauritius is often mistakenly cited but consultation of the primary paper (Staub, 1993) reveals an ill-defined length which is clearly not ML."

Paxton treated these last two size estimates as SLs as opposed to TLs because "squid do not generally leave their tentacles exposed except when grabbing prey and this appears to be the case for Architeuthis".

Berzin's (1972) Indian Ocean claim is suspect because of the roundness of the figure, the lack of detailed measurements and because in an associated photo, the mantle (whose length was not given) does not look very large compared to the men in the image.

[120] Paxton considered the "longest visually estimated" TL to be the 60 ft (18 m) published by Murray (1874:121), from an eyewitness account by fisherman Theophilus Picot, who claimed to have struck the floating animal from his boat, causing it to attack.

Based on a detailed examination of a number of large specimens from New Zealand waters, Förch (1998:55) wrote that "[t]he largest suckers [...] on the sessile arms are a very constant 21–24 millimetres [0.83–0.94 in] in external diameter".

In giant squid the largest suckers of all are found on the central portion of the tentacular club, called the manus, and among the specimens examined by Förch (1998:53) these reached a maximum diameter of 28–32 mm (1.10–1.26 in).

Since there is a cubic relationship between the linear dimensions of Architeuthis and its volume or weight, this means the Thimble Tickle monster must have scaled about 2.8 tonnes [6,200 lb] (i.e. the weight of a large bull hippopotamus), although 2 tonnes [4,400 lb] is probably a more realistic figure.The maximum size of the giant Pacific octopus (Enteroctopus dofleini) has long been a source of debate in the scientific community, with dubious reports of specimens weighing hundreds of kilograms.

It would appear that octopuses weighing as much as 272 kg (600 lb) and with radial spans of over nine metres (30 feet) are within the realm of possibility, but have never actually been documented by both measuring and weighing.No specimens approaching these extreme sizes have been reported since the middle of the 20th century.

This lack of giant individuals is corroborated by commercial octopus fishers; none of those interviewed by Cosgrove & McDaniel (2009) had caught a single animal weighing more than 57 kg (126 lb) in the previous 20 years, among many thousands harvested over that period.

In particular, high concentrations of heavy metals and PCBs have been identified in the digestive glands of wild giant Pacific octopuses, likely originating from their preferred prey, the red rock crab (Cancer productus).

Additionally, females of the octopus genus Argonauta secrete a specialised paper-thin eggcase in which they reside, and this is popularly regarded as a "shell", although it is not attached to the body of the animal (see Finn, 2013).

Early last month Mr. Smith, a local fisherman, brought to the [Colonial] Museum the beak and buccal-mass of a cuttle which had that morning been found lying on the "Big Beach" (Lyall Bay), and he assured us that the creature measured sixty-two feet [18.9 m] in total length.

I that afternoon proceeded to the spot and made a careful examination, took notes, measurements, and also obtained a sketch, which, although the terribly heavy rain and driving southerly wind rendered it impossible to do justice to the subject, will, I trust, convey to you some idea of the general outline of this most recently-arrived Devil-fish.

Wood (1982:191) suggested that, due to the tentacles' highly retractile nature, the total length of 62 feet (18.9 m) originally reported by the fisherman "may have been correct at the time he found the squid", and that "[t]his probably also explains the discrepancy in Kirk's figures".

I lost no time in proceeding to the spot, determined, if possible, to carry home the entire specimen; but judge my surprise when, on reaching the bay, I saw an animal of the size represented in the drawing now before you.

19; see Verrill, 1880a:192], was cast ashore, was out in a boat with two other men; not far from the shore they observed some bulky object, and, supposing it might be part of a wreck, they rowed toward it, and, to their horror, found themselves close to a huge fish, having large glassy eyes, which was making desperate efforts to escape, and churning the water into foam by the motion of its immense arms and tail.

From the funnel at the back of its head it was ejecting large volumes of water, this being its method of moving backward, the force of the stream, by the reaction of the surrounding medium, driving it in the required direction.

Finding the monster partially disabled, the fishermen plucked up courage and ventured near enough to throw the grapnel of their boat, the sharp flukes of which, having barbed points, sunk into the soft body.

But Steve O'Shea commented: The late, great Kir Nesis was not one to exaggerate, and must have had very good reason to cite a possible mantle length of 2.7m [8.9 ft] for Galiteuthis phyllura.

The giant squid ( Architeuthis dux , pictured) was for a long time thought to be the largest extant cephalopod. It is now known that the colossal squid ( Mesonychoteuthis hamiltoni ) attains an even greater maximum size. The giant squid seen here measured 9.24 m (30.3 ft) in total length and had a mantle length of 1.79 m (5.9 ft).
Standard measurements for cephalopods with a squid and octopus as examples
Scientists measuring the mantle width of a large female giant squid of c. 2 m (6.6 ft) ML
Giant squid beak and associated muscles with hand for scale
Egg string and embryos of Haliphron atlanticus , collected north of the Cape Verde Islands . The eggs measure around 8 mm (0.31 in) across the long axis.
Idiosepius paradoxus , a tiny species of squid that grows to 16 mm (0.63 in) in mantle length
Adult male Tremoctopus violaceus with large hectocotylus (arm modified for spermatophore transfer)
The largest cephalopod specimen ever recorded: a 495 kg (1,091 lb) colossal squid
Beak of a colossal squid, which has the largest beak among living cephalopods
The 2007 Ross Sea specimen as it appears now, on display at the Museum of New Zealand Te Papa Tongarewa
A giant squid specimen; the extremely long feeding tentacles of the giant squid make it the longest known cephalopod, past or present.
A giant squid measuring 7 m (23 ft) in total length and weighing 250 kg (550 lb) displayed in a 3.5-tonne (7,700 lb) block of ice at the Melbourne Aquarium [ 54 ]
Dana octopus squid
Onykia robusta grows to a mantle length of at least 2 m (6.6 ft)
Fisherman taking a Humboldt squid off the coast of Chile . This species is the largest squid commonly encountered by humans. [ 68 ]
The giant Pacific octopus is one of the two largest octopus species
The largest known specimen of Parapuzosia seppenradensis , with its describing author, Hermann Landois , who reconstructed its missing living chamber with a combination of wire frame and paper. [ 86 ] Landois assumed that the living chamber constituted one-fourth of the outer whorl , but Teichert & Kummel (1960:6) estimated that it continued for three-fourths to one full whorl, which would give an original shell diameter of around 3.5 m (11 ft).
Reconstructions of the holotype (FHSM 13049) and largest specimen (NDGS 241) of Enchoteuthis melanae , based on Muensterella and Dosidicus
Kubota's photograph of a large Onykia robusta , which was misidentified as the giant squid , Architeuthis dux . Wide-angle photography exaggerated the size of the squid [ 98 ] such that it appeared impossibly large for the species.
The "nearly perfect specimen" that was beached alive in Trinity Bay , Newfoundland , on 24 September 1877. A number of exceptionally large giant squid were reported from Newfoundland in the 1870s, and these were meticulously documented in a series of papers by zoologist Addison Emery Verrill . [ 109 ]
Frequency distribution of total length, mantle length, and mass in Architeuthis dux . The 2,000 lb (910 kg) extreme outlier is sourced from Verrill (1880a) and is unlikely to be accurate; the next most massive individual in the data set was only 700 lb (320 kg), and 95% of specimens were below 250 kg (550 lb). [ 40 ]
Log–log linear regressions for Architeuthis dux : (A) total length vs. mass; (B) mantle length vs. total length; and (C) mantle length vs. mass [ 40 ]
The 19-foot (5.8 m) tentacle that fisherman Theophilus Picot hacked off a live animal on 26 October 1873. Picot estimated the total length of the squid at 60 ft (18 m). [ 118 ]
A dramatisation of an underwater encounter between the sperm whale and giant squid, from a diorama at the American Museum of Natural History
A portion of sperm whale skin with giant squid sucker scars. In this widely reproduced image the largest sucker scars measure around an inch (2.5 cm) across. [ 130 ]
One of the paired tentacular clubs of Architeuthis , showing the enlarged suckers of the manus, which are the largest found on any of the giant squid's limbs
A dozen people attempting to move a giant squid weighing in excess of 200 kg (440 lb) [ 139 ]
Frequency distribution of mass and interocular distance in male and female Enteroctopus dofleini [ 40 ]
Log–log plot showing relationship between interocular distance and mass in Enteroctopus dofleini [ 40 ]
Teuthologist Clyde Roper lying alongside a large giant squid ( Architeuthis dux ) specimen of almost 2 m (6.6 ft) ML
Reaching a mantle length of 2 m (6.6 ft), Onykia robusta is one of the largest squid species (the specimen shown here is considerably smaller).
A 52 lb (24 kg) Humboldt squid ( Dosidicus gigas ) caught off the southern Californian coast displaying deep red chromatophoric colouring.
Enteroctopus dofleini at the National Aquarium in Washington, D.C.
Sepia apama , the largest species of cuttlefish, is native to the southern coast of Australia.
Sepia pharaonis , a large and commercially important cuttlefish species from the Indian Ocean
Bobtail squids , such as this Euprymna berryi from East Timor , are some of the smallest of all cephalopods and are not known to attain a mantle length in excess of 10 cm (3.9 in).
'Archie', a giant squid specimen at the Natural History Museum in London , measures 8.62 m (28.3 ft) in total length (see Ablett, 2012 for more on this specimen)
A bigfin squid (cf. Magnapinna ), one of the longest known cephalopods. This specimen was filmed in October 2000 by DSV Alvin in the Gulf of Mexico , at 1,940 m (6,360 ft) depth.
A freshly caught specimen of Ommastrephes bartramii from northern Hawaiian waters. This species grows to a total length of 2 m (6.6 ft).
Large specimens of Enteroctopus dofleini can exceed 3 m (9.8 ft) in total length.
The 495-kilogram (1,091 lb) colossal squid on display at the Museum of New Zealand Te Papa Tongarewa . It is the most massive extant cephalopod on record.
The largest documented specimen of T. danae , preserved at the National Museum of Natural History . It originally weighed 161.4 kg (356 lb) and had a mantle length of 160 cm (5.2 ft).
A very large mature female of Onykia robsoni with a mantle length of 88.5 cm (2.90 ft) and total weight of 11.1 kg (24 lb)
Lepidoteuthis grimaldii female measuring 61.7 cm (2.02 ft) in mantle length and weighing 4.07 kg (9.0 lb), from the Chatham Rise off New Zealand (note the prominent dermal cushions , likely used for buoyancy )
The maximum weight of the giant Pacific octopus ( Enteroctopus dofleini ) has been much debated, with numerous reports of specimens exceeding 100 kg (220 lb)
Sepia latimanus is the second largest cuttlefish species, closely rivalling S. apama in both mantle length and mass.
Eggcases of six extant Argonauta species (not to scale)
A giant specimen of Argonauta hians from Taiwan , which—at roughly 121.5 mm (4.78 in) in diameter—approximates the length of the official world record size shell.
Young A. argo female with eggcase
Nautilus shells: N. macromphalus (left), A. scrobiculatus (centre), and N. pompilius
Nautilus belauensis off Palau
Two examples of the small internal shell of Spirula spirula
The largest ammonite ever found, a specimen of Parapuzosia seppenradensis measuring 1.742 m (5.72 ft) in diameter. The fossil pictured is the original held at the Westfälisches Museum für Naturkunde in Münster , but many casts exist.
The earliest discovered fossil of P. seppenradensis , as it appeared at the Westphalian Museum of Natural History in 1895. A human skeleton provided scale, while an oil painted background reconstructed the living chamber and animal itself, together with assorted Cretaceous sealife.
The largest ammonite ever found in Bulgaria : a 1.44 m Parapuzosia sp. collected near Shumen in 1932. It is on display at the National Museum of Natural History in Sofia .
Giant fossil of Pachydesmoceras pachydiscoide from Mikasa , Hokkaido , Japan , exhibited at the National Museum of Nature and Science in Tokyo
Titanites giganteus at the Natural History Museum in London
The uncoiled shell of Baculites grandis , a species of heteromorph ammonite
Fossilised guards of the Jurassic belemnites Megateuthis gigantea (top two) and Megateuthis aalensis
Fossilised rostrum of Acroteuthis subquadrata
Endoceras orthocones
Artist's reconstruction of Orthoceras sp., an orthocerid of the Middle Ordovician
Preserved giant squid eye
Gonatus sp. swimming past a submersible during a dive to the Kermadec Arc off New Zealand . Gonatids such as this have proportionately slightly larger eyes than do giant squid. [ 165 ]
Iridoteuthis iris is an extreme example of a sepiolid with disproportionately large eyes
Diagram showing the three major elements (red, green, and yellow) of the squid giant neuronal system. The arrows indicate the direction of transmission from the head ganglion towards the mantle. The funnel (light blue) is the site of rapid water expulsion following mantle contraction.
A dissected male specimen of Onykia ingens , showing an erect 67 cm (2.20 ft) penis approximating the combined length of the mantle, head, and arms
T. W. Kirk 's sketch of the Architeuthis longimanus type specimen in lateral aspect, from Kirk (1888) . Note the extreme length of the feeding tentacles relative to the mantle and arms.
Giant squid beak being measured. Isolated beaks found in the stomachs of predators such as sperm whales can be used to estimate the size of the original animal. [ 122 ]
Drawing of Galiteuthis phyllura from the Bulletin of the United States Fish Commission (1881), showing the proportionately short length of the arms and tentacles