page_title: Cephalopod size
section_title: Largest reported animals
hierarchical_section_title: Cephalopod size / Maximum size / Historical claims / Giant Pacific octopus / Largest reported animals
caption_attribution_description: English: Figure 11: Linear regression between Log10 Interocular Distance (m) and Log10 Mass (kg) for Enteroctopus dofleini.
context_page_description: Cephalopods vary enormously in size. The smallest are only about 1 centimetre long and weigh less than 1 gram at maturity, while the largest—the giant and colossal squids—can exceed 10 metres in length and weigh close to half a tonne, making them the largest living invertebrates. Living species range in mass more than three-billion-fold, or across nine orders of magnitude, from the lightest hatchlings to the heaviest adults. Certain cephalopod species are also noted for having individual body parts of exceptional size. The giant and colossal squids, for example, have the largest known eyes among living animals.
  Cephalopods were at one time the largest of all organisms on Earth, and numerous species of comparable size to the largest present day squids are known from the fossil record, including enormous examples of ammonoids, belemnoids, nautiloids, orthoceratoids, teuthids, and vampyromorphids. In terms of mass, the largest of all known cephalopods were likely the giant shelled ammonoids and endocerid nautiloids, though perhaps still second to the largest living cephalopods when considering tissue mass alone.
  Giant cephalopods have fascinated humankind since time immemorial.
context_section_description: In 1885, reporting on the longest octopus specimen reliably recorded up to that point, renowned malacologist William Healey Dall wrote:
  In 1874 I speared an octopus in the harbor of Iliuliuk, Unalashka, which was afterward hung, by a cord tied around the body immediately behind the arms, to one of the stern davits of the coast survey vessel under my command. As soon as the animal died and the muscles relaxed, I noticed that the tips of the longer tentacles just touched the water. On measuring the distance with a cord, I found it to be sixteen feet [4.9 m], giving the creature a spread from tip to tip of the longest pair of arms, of not less than thirty-two feet [9.8 m]. The arms toward the tips were all exceedingly slender, but rather stout toward the body, which was somewhat over a foot [30 cm] long. The largest suckers were two and a half inches [6.4 cm] in diameter; the whole creature nearly filled a large washtub. Parts of this specimen are now in the U. S. national museum. (Dall, 1885:432)
  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 [45 kg] 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 [32 kg] with a stretched length of 15 feet [4.6 m] 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 [272 kg] and measuring 32 feet [9.8 m] from arm tip to top. MacLean's photographs, unfortunately, were of poor quality. Smaller animals, to 400 pounds [181 kg], 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 [31 ft] and a weight of 272 kg [600 lb]". 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 (McClain et al., 2015). Murray Newman, director of the Vancouver Aquarium for 37 years, quoted Jock MacLean in his 1994 memoir, Life in a Fishbowl: "Next year [1957] in the same place, I saw one, maybe thirty-two feet [9.8 m] across and six hundred pounds [272 kg]. Didn't go for her, though, no place to keep her!" (Newman, 1994:66). 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 198 kg (437 lb) animal with an arm span of 8.5 m (28 ft) near Port Hardy, British Columbia, in March 1956 (Newman, 1994:66; Cosgrove & McDaniel, 2009:66–67). Another giant specimen was caught off Santa Barbara, California, in 1945. Its weight was recorded as 182.3 kg (402 lb) and the surviving photograph makes it possible to estimate its total length at more than 3 m (9.8 ft) and arm span at 6–6.7 m (20–22 ft) (Cosgrove & McDaniel, 2009:67–69). In a book dedicated to the giant Pacific octopus, Cosgrove & McDaniel (2009:72) summarised knowledge on the species's maximum size as follows:
  The specimen William Dall speared in 1885  [sic] at Iliuliuk had the largest radial span of any giant Pacific octopus ever measured. Jock MacLean's 1956 Port Hardy behemoth was the biggest ever weighed. The Santa Barbara specimen photographed in 1945 was the second heaviest. It would appear that octopuses weighing as much as 272 kg (600 lb) and with radial spans of over nine metres (30 ft) are within the realm of possibility, but have never actually been documented by both measuring and weighing.
caption: Log–log plot showing relationship between interocular distance and mass in Enteroctopus dofleini, from McClain et al. (2015)
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