Cephalopods · Oegopsida · Cranchiidae

Colossal Squid

Mesonychoteuthis hamiltoni

Least Concern

The species is abundant and widely distributed; it faces no significant short-term risk. See full glossary

The colossal squid — known in Spanish as calamar colosal or cranquiluria antártica — is regarded as the largest squid species and the only member of the genus Mesonychoteuthis. It is sometimes called, in Spanish, calamar antártico or calamar gigante, and it is believed to be the largest squid species in terms of mass. On current calculations it is estimated to reach a maximum size of between 12 and 15 m, based on analysis of small, not fully grown specimens; the longest individual ever caught is about 4.2 m. The maximum estimated weight is around 750 kg, based on partial remains found in 1925 in the stomach of a sperm whale. It should be borne in mind that its two long prehensile tentacles contribute to that length.

Weight

up to 495 kg

Size

up to 7 m

Diet

Carnivore

Feeds mainly on other animals.

Social structure

Solitary

Lives and hunts alone, joining others only to breed.

Sighting difficulty

Easy

OceanPolarCarnivore Solitary Ocean Polar Mollusc

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Fun facts

GeneralIt has the largest eyes in the animal kingdom, at 27 cm across.
récordIt is the largest invertebrate known, and its eyes can be up to 30 centimetres across, the largest recorded anywhere in the animal kingdom.
It is the heaviest invertebrate on the planet: the largest individual ever weighed was an adult female of 495 kg caught in the Ross Sea in 2007.
It has the largest eyes in the animal kingdom, some 25 to 27 cm across, adapted to the gloom of deep Antarctic water.
Unlike the giant squid, which has suckers with toothed rings, its tentacles carry swivelling hooks, twenty-five in two rows on each tentacular club.
It was identified in 1925 from two arms recovered from a sperm whale's stomach. For a century almost everything known about it came from remains in the stomachs of whales and birds, and from individuals tangled in fishing gear.
In March 2025, exactly a century after it was described, one was filmed alive in its own environment for the first time: a transparent 30 cm juvenile, at 600 m depth, near the South Sandwich Islands.
It floats effortlessly thanks to low-density ammonium-rich tissues, typical of the glass squids.