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The Colossal Squid – From the depths of the Southern Ocean

The Colossal squid, Mesonychoteuthis hamiltoni, are mysterious and the largest of all the cephalopods. Predators of the deep with shredding beaks, rotating and serrated arm hooks, and basketball sized eyes with built-in lights.

The Colossal squid, Mesonychoteuthis hamiltoni, are mysterious creatures and the largest of all the cephalopods. Rarely seen, most of them live in the Southern Ocean below 1000 metres (about 3300 feet). These massive squid can measure up to 14 metres (about 46 feet) in total length with mantle lengths of up to 4 metres (about 13 feet) and weighing up to 495 kilograms (about 1091 pounds).

In 2007, fishermen on the vessel San Aspiring bring up the largest Colossal squid specimen known to date.
See highlights from the Colossal squid examination as specialists in squid biology from Auckland University of Technology undertake research on this rare find, stored at Te Papa Museum.

The largest known Colossal squid was captured in the freezing Antarctic waters of the Ross Sea in 2007, and examined by experts in 2008. It was brought to the surface as it fed on an Antarctic toothfish that had been caught on a long line.

The Colossal squid has the largest eyes in the animal kingdom, and quite possibly the largest that has ever existed on this planet. Each eye measures about 27 centimetres across (just over 10.5 inches) — about the size of a dinner plate or a basketball.

Two parts of the Colossal squid’s eye lens dissected from the Te Papa Colossal squid specimen.

Another amazing thing about the Colossal squid’s eyes is that they have built-in light organs called photophores giving them bioluminescence. Colossal squid also have forward facing eyes giving them binocular vision allowing for depth perception.

So vision is very important to the Colossal squid living in the dark depths of the world’s ocean; they need it to hunt prey, see other squid, and escape predators. As if built-in lights wasn’t enough, these giants have the largest beaks of any squid, and 25 rotating hooks found in two rows on the ends of their tentacles.

Colossal squid have tentacle hooks that can rotate, while their arm hooks are set with serrated suckers above and below them.
The Colossal squid uses its beak to chop and slice up prey before the food is swallowed.

Colossal squid seem to prefer cold waters because that is where specimens have been found and recorded, particularly around the Southern Ocean. However their true range is not well known because they are not easily observed. It is believed that they feed on prey such as Chaetognatha (a predatory marine worm), large fish such as the Antarctic and Patagonian toothfish, and other deep sea squid.

Range of the Colossal squid in the southern hemisphere (in blue).

It is known that Colossal squid are a major prey item for Sperm whales, because their beaks have been found in the stomach contents of the whales. It is also believed that the squid often fight Sperm whales when they are being hunted. Sperms whales will bare scars from injuries that are consistent with the design of the hooks on the tentacles of the squid. Imagine the battle these giants must have down in the deep cold ocean depths.

While we don’t know much about these magnificent animals, all known information has come from dead or dying specimens. They are not considered dangerous to humans, but with their size, and that arsenal of hooks, arms and formidable beak, maybe there is some truth to the tales of the legendary Kraken?

Imaginary view of a gigantic Kraken seizing a ship. There has been anecdotal accounts suggesting that a giant northern hemisphere counterpart of the colossal squid may exist, possibly giving rise to the extraordinary legends of the Kraken…

Contributor: Noel Jhinku

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