Scientifically validated records Squids are the largest living cephalopods in terms of each of
mantle length, total length, and mass, with the largest species by at least two of these measures being the
colossal squid,
Mesonychoteuthis hamiltoni. Reaching an estimated in mantle length and in total length, and weighing as much as , this species is also the largest of all
extant invertebrates. The only other squid that approaches these dimensions is the
giant squid of the genus
Architeuthis, with females up to , in mantle length, and possibly as much as in total length, making it likely the longest of all cephalopods. The two largest
octopus species—
Enteroctopus dofleini and
Haliphron atlanticus—can both exceed , and the former has a maximum total length of more than .
Cirrate (finned) octopods can also reach a large size, with the largest captured specimen likely being a
Cirrothauma magna of total length and mantle length, though observations from submersibles suggest that members of this group can exceed in total length. Members of the other cephalopod groups are substantially smaller, although the largest
cuttlefish can exceed in weight and in mantle length. 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.
Colossal squid (Mesonychoteuthis hamiltoni) 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.
McClain et al. (2015) stated that only 12 "complete" specimens were known. The largest known complete specimen of the colossal squid was a mature female captured in the
Ross Sea in February 2007. Its weight was initially estimated at , its mantle length at , and its total length at . Once completely thawed the specimen was found to weigh , but to measure only in mantle length and in total length. It is likely that the specimen, and particularly its tentacles, shrank considerably
post mortem as a result of dehydration, having been kept in a freezer for 14 months. (As reported by the
Museum of New Zealand Te Papa Tongarewa, specimens of
Nototodarus sloanii, the New Zealand arrow squid, can shrink by as much as 22% when dehydrated with alcohol solutions. The fins of the 2007 Ross Sea specimen measured around across and it had a mantle width of . The arms ranged in length from , while the two tentacles were around long4.6 m-->. Beaks recovered from sperm whale stomachs indicate the existence of animals surpassing even the 2007 Ross Sea specimen. That specimen had a
lower rostral length (LRL) of and weighed , whereas the submature female from 2003 had a LRL of . By comparison, the largest known colossal squid beak from a sperm whale stomach measured in LRL. Unlike the colossal squid, the giant squid is known from a substantial number of mature specimens. The
total number of recorded specimens (across all developmental stages) approaches a thousand, with approximately 700 documented , of which around 460 had been measured in some way. This number has since increased substantially, with 57 specimens recorded from Japanese waters during an exceptional 15-month period between 2014 and 2015. Based on a 40-year data set of more than 50 giant squid specimens,
Roper & Shea (2013:114) suggest an average total length at maturity of and a "rarely encountered maximum length" of . Of the nearly 100 specimens examined by
Clyde Roper, the largest was " long".
O'Shea & Bolstad (2008) give a maximum total length of for females based on the examination of more than 130 specimens, measured
post mortem and relaxed, as well as beaks recovered from
sperm whales (which do not exceed the size of those found in the largest complete specimens).
Steve O'Shea estimated the maximum total length for males at . Older records of or more were likely exaggerated by stretching of the long
feeding tentacles or resulted from inadequate measurement methods such as pacing. O'Shea has stated that, given the available evidence, the highest
upper bound he would consider plausible for the giant squid's total length would be , and that the likelihood that there exist 20-metre giant squid is "so exceedingly remote that you couldn't justify the effort in writing about it". Including the head and
arms but excluding the
tentacles (standard length, SL), the species very rarely exceeds according to
O'Shea & Bolstad (2008).
Paxton (2016a) considers to be the greatest reliably measured SL, based on a specimen reported by
Verrill (1880a:192), and considers specimens of SL or more to be "very probable", but these conclusions have been criticised by giant squid experts.
O'Shea (2003a) put the maximum weight of female giant squid at , based on the examination of some 105 specimens as well as beaks recovered from
sperm whales (which do not exceed the size of those found in the largest complete specimens). Giant squid are
sexually size dimorphic, with the maximum weight for males estimated at , and a specimen).
Roper & Jereb (2010a:121) give a maximum weight of up to , and "possibly greater". Discredited weights of as much as a
tonne () or more are not uncommon in older literature (see
below).). In July 2010, a
sperm whale was photographed off the
Azorean island of
Faial with a large squid—likely
T. danae—in its mouth. The specimen's maximum width, from fin tip to fin tip, was estimated at ; this would approximate its mantle length. '' grows to a mantle length of at least
Onykia robusta, previously known as
Moroteuthis robusta and sometimes called the robust clubhook squid, has a mantle length of up to . Some older records exceed this, such as the ML reported by
Verrill (1876:237) from a specimen with a total length of (excluding the ends of the tentacles, which had been destroyed).
Nesis (1987:192) likewise gave a maximum mantle length of , but
Roper & Jereb (2010i:364) wrote that "this old record might be in error", with the species commonly growing to ML.
Glaubrecht & Salcedo-Vargas (2004:66) provided a maximum total length of . Literature sources give a maximum weight of . There exist numerous published records of large individuals of this species. off the coast of
Chile. This species is the largest squid species commonly encountered by humans, possessing a large fishery. The
Humboldt squid (
Dosidicus gigas), also known as the 'jumbo squid', grows to a maximum mantle length of at least , if not . The largest animals are found off the western coast of
South America; northern populations reach ML, and in general ML is more typical for the species. Southern populations may have a total length approaching , Again, specimens from the
Northern Hemisphere are much smaller, with those off the
Californian coast reaching total lengths of less than . The Humboldt squid commonly attains a weight of around There are anecdotal reports of much larger individual animals, including from diver
Scott Cassell, who has dived with Humboldt squid over 300 times (reportedly more than any other person).
Moroteuthopsis longimana, previously
Kondakovia longimana and sometimes known as the giant warty squid, is a little known species with a circum-
Antarctic distribution in the
Southern Ocean. The largest complete specimen, found floating at the surface off the
South Orkney Islands, had a mantle length of , but a damaged female specimen with an estimated mantle length of around is known. The largest complete specimen had a wet weight of .
Largest octopodes The
giant Pacific octopus (
Enteroctopus dofleini) grows to more than in total length and at least in mantle length.
Cosgrove (1987) and
Cosgrove & McDaniel (2009:69) gave a maximum confirmed weight of for a live specimen collected in the mid-1960s. No specimens approaching this size have been reported since the middle of the 20th century, with recent specimens very rarely exceeding . It is possible that the maximum size of the species has decreased over this period, perhaps due to
bioaccumulation of
toxicants (see
below). In 2002, a giant specimen of
Haliphron atlanticus, the seven-arm octopus, was caught by fishermen trawling at a depth of off the eastern
Chatham Rise,
New Zealand. This specimen, the largest of this species and possibly of all octopuses, was the first validated record of
Haliphron from the
South Pacific. It had a mantle length of , a total length of , and a weight of , although it was incomplete. The total length of the specimen, when complete, has been estimated at , and its weight at .
Extinct taxa '', with its describing author,
Hermann Landois, who reconstructed its missing living chamber with a combination of wire frame and paper. 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 . Certain extinct cephalopods rivalled or even exceeded the size of the largest living species. In particular, the subclass
Ammonoidea is known to have included a considerable number of species that may be considered "giant" (defined by
Stevens, 1988 as those exceeding in shell diameter). The largest confirmed
ammonite, a specimen of
Parapuzosia seppenradensis discovered in a
German quarry in 1895, measures in diameter, though its
living chamber is largely missing. The diameter of the complete shell has been estimated at , assuming the living chamber took up one-fourth of the outer
whorl.
Teichert & Kummel (1960:6) suggested an even larger original shell diameter of around for this specimen, assuming the body chamber extended for three-fourths to one full whorl. In 1971 a portion of an ammonite possibly surpassing this specimen was reportedly found in a
brickyard in
Bottrop, western Germany. A specimen found by Jim Rockwood, from the
Late Triassic near
Williston Lake,
British Columbia, was said to measure more than across, but was later determined to be a
concretion. (FHSM 13049) and largest specimen (NDGS 241) of
Enchoteuthis melanae, based on
Muensterella and
Dosidicus Heteromorph ammonites are known to have exceeded in length also, but since their shells were uncoiled to varying degrees, they were overall much smaller than the largest non-heteromorphs. The greatest lengths of all were reached by the
orthocones of
endocerid nautiloids such as
Endoceras, which may have exceeded , although their maximum size is uncertain; while the largest well documented endocerid fossil is likely the 3-metre-long () shell fragment housed at the
Museum of Comparative Zoology,
Harvard University, there are published reports of even larger specimens.
Teichert (1927) mentioned specimens up to long from the
Middle Ordovician limestone of
Estonia and
Frey (1995:72) gave a maximum shell length of for the group. On the subject of endocerid size, nautiloid specialist
Rousseau H. Flower wrote: They are not all large, by any means, but specimens twelve feet [] in length have been collected, and fragments of greater diameter indicate a much greater maximum length. I am not wholly inclined to discredit a report of an endoceroid found in a quarry near
Watertown New York, which was measured before it was broken up and found to attain a length of . However, the uncoiled length of the largest ammonites far exceeds that of even these giant endocerids.
Parapuzosia seppenradensis, the largest known ammonite species, had an estimated maximum unrolled shell length of around . It was also possibly the heaviest of all known cephalopods, past or present, with an estimated live mass of , of which the shell would constitute 705 kg. By comparison, the largest endocerids may have weighed around . though perhaps still second to the largest living cephalopods when considering
tissue mass alone, since in shell-bearing species the vast majority of the living tissue is restricted to the
body chamber, which occupies only a fraction of the internal shell volume. Unnamed, incomplete upper jaw fossil that is approximately twice as large as that of the mature giant squid is also found there. In 2026,
Nanaimoteuthis haggarti was estimated to be between 7 and 19 m long, making it possibly the largest animal in the Late Cretaceous oceans and even the largest known invertebrate. Though the upper estimates of its body length have been questioned by some reaserchers.
Historical claims Misidentifications , which was misidentified as the giant squid, Architeuthis dux''.
Wide-angle photography exaggerated the size of the squid such that it appeared impossibly large for the species. The maximum sizes of certain cephalopod species, most notably the giant squid and giant Pacific octopus, have often been misreported and exaggerated. The literature on cephalopod size has been further muddied by the frequent misattribution of various squid specimens to the giant squid genus
Architeuthis, often based solely on their large size. In the academic literature alone, such misidentifications encompass at least the
oegopsid families
Chiroteuthidae,
Cranchiidae,
Ommastrephidae,
Onychoteuthidae, and
Psychroteuthidae. This situation is further confused by the occasional usage of the
common name 'giant squid' in reference to large squids of other genera. Perhaps the most notable misidentification relates to a photograph taken some time before 1993 by diver H. Kubota off southern
Japan. The image shows a large individual of
Onykia robusta (previously known as
Moroteuthis robusta), which appears to be sick or dying, alongside a diver in shallow water. If true, this image would represent the first known photograph of a live giant squid. In
The Search for the Giant Squid (1998),
Richard Ellis wrote: For a moment, I thought that some obscure photograph had captured the most elusive image in natural history. Fortunately for those who have devoted their lives to searching for
Architeuthis, this was only an aberration, a case of mistaken identity. Kubodera and his team subsequently became the first to
film a live
adult giant squid on 4 December 2006, and the first to
film a live giant squid
in its natural habitat in July 2012. These milestones were preceded by the first footage of a live (
paralarval) giant squid in 2001, and the first image of a live adult giant squid on 15 January 2002. Since then, live giant squid have been photographed and filmed on a number of occasions.
Giant squid ,
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. Reports of giant squid (
Architeuthis dux) specimens reaching or even exceeding in total length are widespread, but no animals approaching this size have been scientifically documented in recent times. This is despite there being
hundreds of specimens available for study ( 700 documented as of 2015, of which 460 measured in some way though Paxton conceded that it is "[n]ot clear how much/what portion of body was eaten". For the "longest visually estimated", more extreme supposed SLs of and are cited to
Starkey (1963) and
Ellis (1998a:246), respectively (the latter an eyewitness account by Dennis Braun). 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". For total length,
Paxton (2016a:83) considered three records as candidates for the "longest measured": the specimen of
Berzin (1972:199), the specimen described by
Kirk (1888) as
Architeuthis longimanus—a strangely proportioned animal that has been much commented on—and the "
Thimble Tickle specimen" reported by
Verrill (1880a:191), which is often cited as the largest giant squid ever recorded. Of the last one, Paxton wrote: "Sometimes mistakenly cited as but the source is clear that it is 55 ft long." The first two records, particularly that of Berzin, are more questionable, as Paxton explained: The accuracy of the two longest measured TLs of 19 and 16.81 m from a specimen found in the gut of a sperm whale from the Indian Ocean and from the specimen from New Zealand in 1887, respectively, should also be questioned but again are certainly not impossible. The New Zealand specimen (named
Architeuthis longimanus Kirk, 1888) clearly has the largest ratio of TL to ML ever known in
Architeuthis [...] which led
O'Shea & Bolstad, 2008] to suggest that the length was paced out and/or there was extensive post-mortem stretching. However, a re-reading of the original paper suggests that the specimen, although initially paced out, was actually measured, nevertheless the TL is at the edge of the 99.9% prediction interval range [...] and so it was certainly an unusual specimen.
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. Consequently the measurement, if accurate, would represent another animal with very long tentacles. However, as
Paxton (2016a:86) pointed out, the genetic analysis of
Winkelmann et al. (2013)—which concluded that there is likely a single, globally-distributed species of
Architeuthis—did not encompass these two specimens, and it is therefore possible that there exists a second, as yet unsampled, giant squid species with proportionately longer tentacles. The total length of the Berzin specimen was later confirmed to be erroneous; according to Valentin Yukhov, who was involved in the specimen's discovery, it should have read . The misprint was reproduced in the English translation published the following year and was later propagated in a number of papers on giant squid. Paxton considered the "longest visually estimated" TL to be the 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. Picot managed to hack off one of its tentacles, which was subsequently examined by a number of authors. Perhaps the largest of all recorded giant squid specimens was the one found floating at the surface off
Saint-Gilles,
Réunion, on 4 March 2016.
Romanov et al. (2017) used the following allometric scaling equations to estimate the dorsal mantle length (DML) from the
lower rostral length (LRL) of the beak, and total length (TL) from DML: :LRL = 11.2 \times log_{10} DML - 19.3 (all values in mm) :DML = e^{(-1.168 + 98.031 \times LRL)} (all values in m) :TL = 0.006 + 5.117 DML (all values in m)}} the
lower rostral length of the beak, at , gave an estimated dorsal mantle length of and this, in turn, was used to estimate the total length at . The existence of these gargantuan squids is often supported by reference to the giant circular scars sometimes found on
sperm whales, which are assumed to have been inflicted by the
suckers of struggling giant squid. Sometimes these claims are accompanied by extrapolations of body size based on the
isometric upscaling of a "typical" giant squid. However, such scars are not necessarily of squid origin and may instead represent fungal growths or bite marks, with
sea lampreys (
Petromyzon marinus) being one possible source. Even in the case of genuine giant squid sucker marks it is possible that subsequent skin growth has enlarged them well beyond their original dimensions. skin with giant squid sucker scars. In this widely reproduced image the largest sucker scars measure around an inch () across. Nevertheless, claims of enormous sucker scars are widespread in the literature.
Richard Ellis collected some of "the more egregious examples" in his book,
The Search for the Giant Squid. These include the claim of
Dozier (1976) that "an ordinary giant squid of 50 feet [] leaves teeth-ringed sucker marks measuring between three and four inches [] across on a whale, but sperm whales have been captured with tentacle marks 18 inches [] across."
L. Harrison Matthews's monographic treatment of the sperm whale, published in 1938, includes the following: "Nearly all male Sperm whales carry scars caused by the suckers and claws of large squids, scars caused by suckers up to 10 cm. [] in diameter being common. The claw marks take the form of scratches 2–3 m. [] in length, and appear to be of more frequent occurrence than sucker marks".
Ellis (1998a:142) wrote that this 10 cm figure is "so much larger than any other recorded sucker dimensions that one suspects some sort of error, either in measuring or in transcription." The subject was covered in some detail by
Wood (1982:192): Measurements of , and even have been conjectured for giant squids from the size of sucker marks found on the skins of captured sperm whales, but it is dangerous to place too much reliance on this evidence.
Verrill says the largest suckers on the tentacles of a long specimen measured 1 in [] in diameter, and those on a 52-footer [] about .
Daniel (1925), however, examined sucker marks on the head of one cachalot which measured 3 in [] across, and others measuring up to in diameter have been found on the skins of sperm whales captured in the North Atlantic.
Ivan Sanderson (1956) goes even further and claims that sucker marks over have been found on the heads of cachalots, but he does not explain how the poor whales managed to escape from the clutches of such colossi! The general consensus of opinion is that exceptionally large sucker marks, i.e. over in diameter, are old scars that have increased in size as the sperm whale grew. s of
Architeuthis, showing the enlarged suckers of the manus, which are the largest found on any of the giant squid's
limbs Perhaps the most extreme published claim, ridiculed by
Ellis (1998a:142), appeared in
Willy Ley's 1959 book,
Exotic Zoology: "Toothed whales, vomiting in death struggle, have shown evidence of still larger
kraken; in one case a 6-foot [] piece of tentacle,
with a diameter of 2 feet [; emphasis in original], has been claimed. Another claim goes for marks on the skin of such a whale, looking like the mark of a sucking disk over 2 feet [] in diameter". Marine biologist
Frederick Aldrich, who personally examined more than a dozen giant squid specimens, wrote that his largest specimen from
Newfoundland bore tentacular suckers "approximately two inches [] in diameter" but that "[s]uckers and their toothed armament of over twelve inches [] in diameter have been found in the stomachs of sperm whale as indigestible wastes". This led him to entertain the idea of giant squid over long, and even to suggest a
binomial name for this super-sized species, were it ever to be discovered:
Architeuthis halpertius. According to
Roper & Boss (1982:97), the largest suckers of the tentacular clubs reach in diameter.
Mass estimates weighing in excess of It is now accepted that the giant squid has
a maximum mass of several hundred kilograms, but the literature is rife with claims of much greater weights.
Clarke (1966), for example, put the mass of the largest giant squid specimens at around . Similarly,
Richard Ellis wrote: "Where [giant] squid carcasses have actually been weighed, it appears that the longest ones—in the 50-foot [] range, for example—weigh about a ton []." Much greater estimates of giant squid mass can be found in, for example,
Natural History of Marine Animals by
MacGinitie & MacGinitie (1949): "two arms of
Architeuthis that were long were found, and if one reconstructed a body [...] the squid to which these arms belonged was in diameter and long, with an overall measurement of . It would have weighed about 42 tons []." They added that a specimen, such as the one reported from
Thimble Tickle, "would have weighed 29 or 30 tons [] including the tentacles—a truly noble animal, being a little more than one-fifth the weight of the
largest whale and larger than the
whale sharks and
basking sharks, the largest of all fishes". Ellis characterised these estimates as "unfounded exaggerations".
Bernard Heuvelmans believed that "there must be
Architeuthis weighing more than 5 tons, and some even larger ones which must weigh between 2 and 27 tons, the normal weight being around 8 tons. There are good reasons to believe that there may even exist specimens twice as long as that of Thimble Tickle, which, depending upon their girth, might have weighed between 16 and 216 tons, but more likely around 64 tons." Ellis, who considered these estimates "utterly ridiculous", wrote: Heuvelmans commits a fundamental error in calculating the weight of some of these monsters when he writes that "the density of living creatures is only slightly higher than that of water ... a decimetre of living flesh weighs about as much as a litre of water." That may be true for some other living creatures, but the flesh of
Architeuthis, saturated with
ammonium chloride, is
lighter than water, and the giant squid is
neutrally buoyant. (This is believed to be the reason that dead or dying squid are found floating at the surface or washed up on the beach.) His assumption, therefore, that the 55-foot-long [] Thimble Tickle squid would have "probably weighed near 24 tons" is patently erroneous. On the subject of the Thimble Tickle specimen's mass,
Wood (1982:190) referred to the work of
Soviet zoologist and writer
Igor Akimushkin: According to Dr
Igor Akimushkin (1965), the Russian teuthologist, a long giant squid will weigh 1 tonne [] if the head, mantle and arms combined make up half the total length. 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 [] (i.e. the weight of a large bull
hippopotamus), although 2 tonnes [] is probably a more realistic figure.
Giant Pacific octopus 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.
Largest reported animals of mass and interocular distance in male and female
Enteroctopus dofleini In an article for the
National Marine Fisheries Service summarising knowledge on the giant Pacific octopus,
High (1976:17–18) wrote: Several octopuses in excess of 100 pounds [] have been encountered and captured. Much larger ones have been reported but, like the
Loch Ness Monster, these usually elude the careful photographer or scientist. Most octopuses weigh less than 70 pounds [] with a stretched length of 15 feet [] or less. Overall length between arms is not a suitable measure because of the animal's unusual elasticity. In the late 1950s, I interviewed a Canadian commercial diver, Jock MacLean of
Prince Rupert,
B.C. He reported capturing an immense creature weighing 600 pounds [] and measuring 32 feet [] from arm tip to top. MacLean's photographs, unfortunately, were of poor quality. Smaller animals, to 400 pounds [], were occasionally taken in his commercial octopus fishing endeavor.
Hochberg & Fields (1980:436) referenced the same specimen, writing: "the largest specimen on record with a total arm spread of 9.6 m [] and a weight of 272 kg []". These figures are only estimates, however, as—contrary to the above quotation from
High (1976:17–18)—it appears that this specimen was never collected and measured. Nevertheless, the
misleadingly precise metric conversion of 272 kg (for 600 lb) and the
imprecise conversion of 9.6 m (for 32 ft; naively employing a
conversion factor of 0.3 instead of
0.3048) gained wide acceptance as the maximum recorded dimensions of the giant Pacific octopus, and have been much repeated. Jock MacLean is also reported to have
captured a animal with an arm span of near
Port Hardy,
British Columbia, in March 1956. Another giant specimen was caught off
Santa Barbara,
California, in 1945. Its weight was recorded as and the surviving photograph makes it possible to estimate its total length at more than and arm span at . Anderson suggested the species might now be maturing at a smaller size as a result of
toxicant bioaccumulation, which could explain the lack of truly gigantic specimens in recent times. 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). A preliminary study found that aquarium animals fed equal quantities of raw sea food and live
C. productus (caught locally in
Elliott Bay) matured at a smaller size, reached a lower maximum weight ( mean), and had higher concentrations of most heavy metals, than those fed solely on raw sea food ( mean, including the aforementioned specimen).
Largest species by measure Cephalopod size can be quantified in various ways. Some of the most common size measures are covered below. The following four tables list only extant species;
extinct taxa are treated separately at the end.
Mantle length lying alongside a large
giant squid (
Architeuthis dux) specimen of almost ML '' is one of the largest squid species (the specimen shown here is considerably smaller). (
Dosidicus gigas) caught off the southern
Californian coast displaying deep red
chromatophoric colouring. '' at the
National Aquarium in
Washington, D.C. '', the largest species of cuttlefish, is native to the southern coast of Australia. '', a large and commercially important cuttlefish species from the
Indian Ocean s, 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 . The list of largest cephalopods by mantle length is dominated by squids, with more than twenty species exceeding the largest-bodied octopuses and cuttlefish. The largest of all is the
colossal squid (
Mesonychoteuthis hamiltoni) with an estimated maximum mantle length of (
Roper & Jereb, 2010c:173). Even greater mantle lengths have historically been reported for the
giant squid (
Architeuthis dux), but these have been discredited (see
O'Shea & Bolstad, 2008).
Total length specimen at the
Natural History Museum in
London, measures in total length (see
Ablett, 2012 for more on this specimen)
), one of the longest known cephalopods. This specimen was filmed in October 2000 by DSV Alvin'' in the
Gulf of Mexico, at depth. '' from northern
Hawaiian waters. This species grows to a total length of . '' can exceed in total length. The longest scientifically documented specimens belong to the
giant squid, with a maximum total length of (
Roper & Shea, 2013:114). Despite its proportionally shorter tentacles, the
colossal squid may rival the giant squid in total length, but the species's size limits are uncertain because only a handful of mature specimens have been recorded.
Mass . It is the most massive extant cephalopod on record. '', preserved at the
National Museum of Natural History. It originally weighed and had a mantle length of . '' with a mantle length of and total weight of '' female measuring in mantle length and weighing , from the
Chatham Rise off
New Zealand (note the prominent
dermal cushions, likely used for
buoyancy) (
Enteroctopus dofleini) has been much debated, with numerous reports of specimens exceeding
is the second largest cuttlefish species, closely rivalling S. apama'' in both mantle length and mass. The heaviest known cephalopod, and the largest living invertebrate, is the
colossal squid. The largest recorded specimen of this species, caught in the
Ross Sea in 2007, weighed . However, its beak is not the largest known from this species; even bigger colossal squid beaks have been recovered from the stomachs of
sperm whales, indicating that this species can grow larger still.
Shell diameter '' species (not to scale) '' from
Taiwan, which—at roughly in diameter—approximates the length of the official world record size shell. '' female with eggcase
(left), A. scrobiculatus (centre), and N. pompilius'' '' off
Palau ''
Nautiluses are the only extant
cephalopods with a true external shell; in other groups the shell has been internalised or lost completely. Internal shells include the
cuttlebones of cuttlefish, the
gladii of squids and the vampire squid, the
winged shells of cirrate octopods, and the spiral shells of
Spirula. 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). Cephalopod shell diameter is of interest to
teuthologists and
conchologists alike. The
Registry of World Record Size Shells, the most comprehensive publication on maximum shell size in marine molluscs, specifies that specimens "should be measured with
vernier type calipers and should reflect the greatest measurable dimension of the shell in any direction including any processes of hard shell material produced by the animal (i.e. spines, wings, keels, siphonal canals, etc.) and not including attachments,
barnacles,
coralline algae, or any other encrusting organisms" (
Pisor, 2008:14). Unlike most other measures of cephalopod size, shell diameter can be determined with a high degree of precision and usually leaves little room for ambiguity. For this reason it is usually recorded to the nearest one-tenth of a millimetre (), as is standard in
conchology. When the
Registry of World Record Size Shells changed ownership in 2008 it was launched as an online database in addition to its print publication. Subsequent rule changes meant that all records required photographic verification. Over time, older records for which photographic evidence could not be obtained were removed from the database. As a result, some records from older editions of the registry actually exceed the size of the current official record holders, sometimes by considerable margins. Where this has occurred, the largest recorded size across all editions is shown first and any discrepancies or competing records are noted thereafter. Where a reliable literature record surpasses all specimens ever included in the registry, this is given instead and the registry record(s) noted thereafter.
Pisor (2008) was the fifth and final print edition of the registry published prior to the rule change, and
Barbier et al. () is the current, continuously updated online database. The registry only covers the shells of
nautiluses and
Spirula and the eggcases of
Argonauta.
Extinct taxa ever found, a specimen of
Parapuzosia seppenradensis measuring in diameter. The fossil pictured is the original held at the
Westfälisches Museum für Naturkunde in
Münster, but many casts exist. '', 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. : a 1.44 m
Parapuzosia sp. collected near
Shumen in 1932. It is on display at the
National Museum of Natural History in
Sofia. '' from
Mikasa,
Hokkaido,
Japan, exhibited at the
National Museum of Nature and Science in
Tokyo '' at the
Natural History Museum in
London '', a species of
heteromorph ammonite belemnites
Megateuthis gigantea (top two) and
Megateuthis aalensis '' '' orthocones '' sp., an
orthocerid of the
Middle Ordovician ==Anatomical superlatives==