List of colossal squid specimens and sightings
This list of colossal squid specimens and sightings is a timeline of recorded human encounters with members of the genus Mesonychoteuthis, popularly known as colossal squid. It includes animals that were caught by fishermen, recovered (in whole or in part) from sperm whales and other predatory species, as well as those reliably sighted at sea. The list also covers specimens misidentified as colossal squid.
Background[]
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The colossal squid (Mesonychoteuthis hamiltoni), which has a circum-Antarctic distribution in the Southern Ocean, is far less known than the distantly related, near-cosmopolitan giant squid (Architeuthis dux). Though a substantial number of colossal squid specimens have been recorded, the vast majority of these are only fragmentary remains such as disarticulated beaks. Xavier et al. (1999) collated 188 geographical positions for whole or partial specimens caught by commercial and scientific fisheries, but very few mature animals have ever been documented. O'Shea & Bolstad (2008) found 11 reports in which adult or subadult specimens had been described, and mentioned that at least 7 additional, "similarly sized" specimens were known to them; McClain et al. (2015) stated that only 12 "complete" specimens were known.
Early specimens[]
The earliest known specimens of this species are two brachial crowns (#1) recovered from the stomach of a sperm whale in the winter of 1924–1925, on the basis of which Guy Coburn Robson formally described Mesonychoteuthis hamiltoni in 1925.[1] Apart from two partial specimens (#2 and 3) recovered from sperm whale stomachs in the mid-1950s—initially misidentified as belonging to the giant squid genus, Architeuthis[2]—and a single juvenile individual of 86 mm (3.4 in) mantle length (#4),[3] little else was known about the species until additional specimens began receiving coverage in Russian-language scientific journals in the 1970s.[4] In 1981, a Soviet trawler operating off Dronning Maud Land, Antarctica, retrieved a complete specimen (#9) with a mantle length of 2.42 m (7.9 ft) and total length of 5.1 m (17 ft) from a depth of 750–770 m, which was later identified as an immature female of M. hamiltoni.[5]
Emergence from obscurity[]
It would be more than two decades before another giant individual was collected:[6] in March 2003, a complete specimen of a subadult female (#14) was found near the surface in the Ross Sea. It weighed some 300 kg (660 lb), with a total length of around 5.4 m (18 ft) and mantle length of 2.5 m (8.2 ft).[7] It was this specimen that led teuthologist Steve O'Shea to coin the common name "colossal squid".[8] A much smaller immature female (#15) was taken by trawl at 1,143 m (3,750 ft) depth off Macquarie Island the same year.[9] On 25 June 2005, a specimen was captured alive at a depth of 1,625 m (5,331 ft) while taking Patagonian toothfish from a longline in South Georgian waters (#17). Although the heavy mantle could not be brought aboard, the total length was estimated at around 5 m (16 ft) and the animal is thought to have weighed between 150 and 200 kg (330 and 440 lb).[10] It was filmed alive at the surface.[11]
Largest known specimen[]
The largest known complete specimen of the colossal squid—and the heaviest recorded extant cephalopod—was a mature female (#19) captured in the Ross Sea in February 2007. Its weight was initially estimated at 450 kg (990 lb), its mantle length at 4 m (13 ft), and its total length at 8–10 m (26–33 ft).[15] Once completely thawed the specimen was found to weigh 495 kg (1,091 lb), but to measure only 2.5 m (8.2 ft) in mantle length and 4.2 m (14 ft) in total length.[16][nb 2] 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.[nb 3] Both this and the 2003 specimen received significant media attention and did much to bring the species to public prominence; the following years saw a number of individuals of the more commonly encountered giant squid misidentified as colossal squid (e.g. #[1] and [2]).
Later developments[]
Perhaps the best video of a live colossal squid is that of an animal (#21) recorded at the surface in the D'Urville Sea off Antarctica in January 2008.[21] The squid was pulled to the surface feeding on a line-caught toothfish. The video is likely the first to show a colossal squid swimming freely, and records the animal performing a slow roll on its longitudinal axis. Initially light-coloured, the squid quickly turned blood red (possibly a stress response) before returning to a light pink after lingering at the surface for a short time, thence slowly retreated to deeper water.[22]
Another giant specimen, a female measuring 3.5 m (11 ft) in total length and weighing 350 kg (770 lb), was recovered intact in 2014 (#27). It had eyes 37 cm (15 in) across—the largest ever recorded.[23] Its 3.5-hour dissection at the Museum of New Zealand Te Papa Tongarewa was live streamed on YouTube.[24]
Since then, several more colossal squid have been filmed or photographed alive at the surface. But as far as is publicly known, the colossal squid has never been observed alive in its natural, deep-water habitat, although a number of such recordings of the giant squid have been made in recent years.[25] As such, it is the only known extant species of truly giant (>50 kg [110 lb]) cephalopod that has never been filmed in its natural habitat.[nb 4]
List of colossal squid[]
Records are listed chronologically in ascending order and numbered accordingly. This numbering is not meant to be definitive but rather to provide a convenient means of referring to individual records. Specimens incorrectly identified as colossal squid are counted separately, their numbers enclosed in square brackets, and are highlighted in pink ( ). Records that cover multiple colossal squid specimens, or remains of more than a single animal (e.g. two lower beaks), have the 'Material cited' cell highlighted in grey ( ). Animals that were photographed or filmed while alive are highlighted in yellow ( ). Where a record falls into more than one of these categories, a combination of shadings is used. Where an image of a specimen is available this is indicated by a camera symbol (