In March 2013, researchers reported that DNA from giant squid around the world shows they are one species. The 2013 study analysed DNA from the remains of 43 giant squid collected from all over the world.
Because giant squid worldwide are so alike genetically, researchers reasoned that they must migrate long distances to keep the breeding population well mixed.
Scientists proved the squid in the 2004 photographs was a giant squid by taking DNA samples from a piece of its tentacle. As of November 2026, the first photographs of a live giant squid in the ocean were reported in September 2005.
Giant squid are found in all of the world's oceans, usually in association with the slopes of continents and islands. Giant squid have been caught in bottom trawls and in midwater trawls, which hints at a considerable depth range. Researchers are not sure where giant squid live in the water column, although catches by trawlers suggest a depth range of about 300 meters to 1 kilometer, and estimates of the depth range vary: one museum page says specimens were caught at 400 to 800 meters, and another source says 300 to 1000 meters is not unrealistic.
One source describes a zone perhaps 200 to 1,000 meters down, usually called the twilight zone, where light fades quickly. Below 1,000 meters the deep ocean is completely dark, and its average temperature is only 4 degrees Celsius (39 degrees Fahrenheit), while deep-sea pressure is extreme: from about 40 to over 110 times the pressure of Earth's atmosphere. Cameras in a 2021 study recorded giant squid and other deep-sea squid in the Gulf of Mexico and near the Bahamas at depths between 557 and 950 meters.
Giant squid are not only hunters of fish. A giant squid eats fish that live in the deep sea, and juvenile giant squid have been taken from the stomachs of deep-sea fishes, so they are part of the deep-sea food web.
Sperm whales, the largest of the toothed whales, eat mostly squid. A squid's hard, parrot-like beak is not easily broken down, so beaks can be found in a whale's stomach after the soft body is digested, and researchers can measure chemicals in squid beaks recovered from whale stomachs, and these measurements reflect both what and where the animals ate.
Almost everything scientists know about giant squid comes from carcasses washed up on beaches or hauled in by fishermen.
Giant squid tentacle clubs are narrow and elongate, with suckers in four lengthwise rows, while the arms have suckers in two rows. The suckers cover only the inner surface of the arms and tentacles.
A giant squid swims by jet propulsion: its stretchy mantle snaps back and jets water out through the funnel.
A squid's circulatory system is closed, and its blood does not carry oxygen very well at higher temperatures, which fits life in cold deep water.
As of November 2026, the IUCN Red List lists the giant squid as Least Concern, last assessed 28 April 2010. Researchers do not know how many there are.
Words to know
- migrate: travel far
- genetically: by DNA
- juvenile: young animal
- trawls: fishing nets
