Why giant squid, the once mythical kraken of the deep, are still mystifying scientists 150 years after they were discovered

NASAThis giant squid carcass is over 16 feet long.

The Kraken, the mythical beast of the sea, is real.

Giant squid live in the dark depths of the ocean, and very little is known about them to this day.

Most of what the world has learned about the gargantuan creature, which can grow up to 40 feet long and live in a world devoid of sunlight, is taken from their floating carcasses, or from the belly of sperm whales.

Until 2005, no scientist had ever photographed a living giant squid. One hadn’t been filmed until 2013. But scientists believe there are millions of them out there.

In June, a NOAA Office of Ocean Exploration and Research expedition captured the first footage of a giant squid in American waters.

The New Yorker’s David Grann wrote that giant squid can be “larger than a whale and stronger than an elephant, with a beak that can sever steel cables.”

Here’s what is known about the mysterious beast, and why so much is still not known.


Living 1,300 to 3,000 feet down in the ocean, giant squid inhabit the deepest, darkest places in the world. No one knows for sure how long they live for, how they find partners, how they migrate, where they lay their eggs, or even if they make any sounds. To put it bluntly, the giant squid remains a mystery.

Sources: Smithsonian Magazine, The Atlantic, BBC, National Museum of Natural History


Genetics show they have been around for about 730,000 years. They have been in human legends for hundreds of years. Giant squid are the inspiration for the “Kraken” in Norse mythology, and the beasts in Jules Verne’s book “20,000 Leagues Under the Sea.”

WikimediaAn illustration from the original edition of Twenty Thousand Leagues Under the Sea depicting a giant squid

Sources: Smithsonian Magazine, The New York Times, BBC


One particularly good story was written in “The Natural History of Norway” in 1755, which described the giant squid as being as large as “a number of small islands,” and when the giant squid began to sink, it caused whirlpools that sucked everyone down with it.

Universal History Archive/Universal Images Group / GettyLegendary Kraken, monster of the deep, pictured as a giant squid. Engraving 1870.

Source: BBC


Until about 150 years ago, most people didn’t think they were real. They were sea monsters made up by sailors. But their existence started to become more plausible. One factor was finding sucker scars, like burn marks all over sperm whales, their main predator. Their beaks have also been found in the whales’ stomachs. These were signs of the deep sea battles waged between whale and squid.

WikimediaA portion of sperm whale skin with giant squid sucker scars.

Source: The New Yorker


In 1857, Japetus Steenstrup, a Danish zoologist at the University of Copenhagen, introduced the giant squid into the scientific community. After studying a beak that washed up in Denmark, he published his research and confirmed to the world the giant squid was in fact real. He named them Architeuthis Dux, which is Latin for “ruling squid.”

WikimediaJapetu Steenstrup

Sources: Smithsonian Magazine, The Conversation, BBC


In 1873, three fisherman in Conception Bay, Newfoundland, came upon a giant squid that tried to sink their boat. They fought it off, and the squid escaped after releasing dark clouds of ink. But the fishermen managed to secure 19 feet of tentacle — more proof of the mythic squid’s existence.

WikimediaGiant squid from Logy Bay, Newfoundland in bathtub, November/December, 1873

Source: Smithsonian Magazine


What made the giant squid tantalising was that their carcasses washed up reasonably often, but it was unheard of for anyone, other than fishermen, to see them alive.

NTNU Museum of Natural History and Archaeology, 1954Giant squid found in Ranheim, Norway, in 1954 measured by Professors Erling Sivertsen and Svein Haftorn.

Source: Slate


The reason so many carcasses have been found by fisherman is because giant squid are filled with ammonium ions, which are lighter than seawater, causing them to float after they die.

The Asahi Shimbun / GettyA researcher measures the body length of a giant squid at Ajiro Shinko Port on January 21, 2014 in Iwami, Tottori, Japan. The 3.4 meters long giant squid was caught during the trawl fishing.

Source: “Shark Trouble: True Stories and Lessons About the Sea”


In 1997, US National Geographic tried to use sperm whales to study the giant squid. They attached video cameras, hoping to see the whale eating the squid. But they weren’t successful.

Sources: Smithsonian Magazine, Sydney Morning Herald


Despite Streenstrup’s early success, few people have been able to make a career out of studying giant squid alone, again because they appear so rarely. For marine ecologist Angel Guerra, who here is dissecting a giant squid, it’s like a “hobby.”

Fernando Camino / GettyAngel Guerra extracts a giant squid bite in 2003.

Sources: The Atlantic, The New Yorker


New Zealand marine biologist Steve O’Shea, whom The New Yorker dubbed “The Squid Hunter,” was for a time one of the most well-known giant squid scientists. His quest began in 1996, and ended in 2011.

WikimediaSteve O’Shea dissecting a squid.

Asked why he kept going for so long, he told Business Insider he made a vow after a failed attempt to chronicle the life of giant squid from being a juvenile, onwards.

“At the end of it all, camera thrown in my face, tears streaming, dreams destroyed, lifeless corpses of juvenile giant squid in the palm of my hand, I recall vowing to continue my insane quest until I achieved what I’d set out to do, or someone else did,” he said.


One of O’Shea’s goals had been to unveil giant squid to the public in an aquarium. He wanted everyone, not just scientists and fishermen, to experience “the majesty of these animals” up close and personal, rather than watching a fleeting, grainy image on a television screen.

Ian Nicholson / PA images / GettyJohn Ablett, Mollusc Curator at the Natural History Museum, London, Tuesday 28th February 2006, with a giant squid about to go on display at the museum’s Darwin Centre.

In 2003, O’Shea led a team trying to document the giant squid as they migrated into New Zealand waters. His plan was to grind up squid sex organs and squirt them into the water to get squids to mate with the camera lens.

Fernando Camino / Cover / GettyTwo female giant squids.

He told BBC, “The freezer bag at home – to my wife’s disgust – is actually full of giant squid gonad samples. We’re going to grind all of this up, and we’re going to have this puree coming out from the camera, squirting into the water.”

He said “the dream” was to get “sensational footage of the giant squid trying to do “obscene things” with the camera. The experiment failed.


Then, on September 30, 2004, the giant squid became a little less mythic. Marine biologists Tsunemi Kubodera and Kyoichi Mori took the first-ever photo of a living giant squid off the coast of Japan’s Chichijima Island, where sperm whales were recorded with suction marks.

Sources: The Sydney Morning Herald, BBC


They lowered a hook with a camera and bait down 3,000 feet. A giant squid attacked, and used its tentacles to envelop the bait, like a python envelopes its prey. After four hours of trying to free its tentacles, it died.

National Science Museum / APA 26-foot-long Architeuthis attacks a prey hung by a white rope, left, at 900 meters (yards) deep off the coast of Japan’s Bonin islands, 1,000 kilometers (670 miles) south of Tokyo, in the fall of 2004.

Sources: The Sydney Morning Herald, BBC


Tsunemi said the incident changed the perception of giant squid being a laid-back, deep-sea drifter, and gave way to an image of a quick and agile predator of the deep.

Eriko Sugita / ReutersJapanese researcher Tsunemi Kubodera smiles as he shows a giant squid on display at the National Science museum in Tokyo September 28, 2005.

Sources: Slate, PBS


Tsunemi was on a roll. In 2006, his team published the first video of a live giant squid. It was relatively small, at 110 pounds and 11 feet long, but it was the first moving pictures of the creature. “Nobody has ever seen a live giant squid except fishermen,” he told Reuters.

Tsunemi Kubodera of the National Science Museum of Japan, HO/APA giant squid attacks a bait squid is being pulled up by his research team off the Ogasawara Islands, south of Tokyo, on Dec. 4, 2006.

Sources: Slate, BBC, Reuters


In 2007, a 6.5-foot long, 550-pound giant squid washed up in Tasmania. With its tentacles it measured 26 feet — the same length as a bus. Tasmanian Museum curator David Pemberton said it was one of the biggest ever discovered. The squid was thought to be feeding on grenadier fish in Australia’s cold winter waters.

Tasmanian Museum and Art Gallery / Simon Cuthbert / Handout / ReutersThe beak and mouth of the giant two-metre squid which washed up on the shores of Tasmania’s Ocean Beach.

Sources: Reuters, CBC, Sydney Morning Herald


In 2012, the giant squid was recorded in its natural habitat for the first time. The trick to it was using a camera, designed by marine biologist Edith Widder, which emitted a blue light, like the light produced by a type of jellyfish known as Atolla. The squid they caught on camera wrapped itself around the camera, and confirmed to the scientists that it was a predator.

Discovery ChannelThe Discovery Channel had a documentary about the journey to capture the footage of a giant squid in its natural habitat.

Sources: BBC, NPR, Edith Widder’s TED talk


Widder told the BBC there were probably millions in the oceans, since they kept so many sperm whales fed. It’s because humans scared them off that more hadn’t been seen. So, knowing this, she designed a camera without thrusters or a motor. The only illumination was red light that’s invisible to deep-sea animals, because they have adapted to primarily seeing blue.

Eric Risberg / APMarine scientist Edith Widder inspects a 502-pound deep sea video camera ‘Eye-in-the-Sea’ aboard the Research Vessel Point Lobos, on Monterey Bay, Calif., Wednesday, Jan. 21, 2009.

Source: BBC, NPR


O’Shea was on board for the momentous occasion. “This proved to be the last time I would be in front of the camera chasing this infernal animal,” he said. “When Ku achieved the end game, securing the most stunning imagery of the animal alive, there was no further need for folk like me or my dreams.”

Discovery ChannelThe scientists on board were very excited to film the giant squid.

More evidence was gathered in 2016, when a young female giant squid weighing 231 pounds washed up dead on the Bares peninsula in Spain. Its death pointed to the possibility that giant squid kill each other for food piracy.

Alonso Gonzalez / ReutersSpanish fishermen show off a ‘Taningia Danae’, or giant squid in Gijon, northern Spain on August 29, 2002

In northern Spain waters, giant squid feed on fish called blue whiting, which swim near the surface. The giant squid has to ascend to the surface to catch them. Scientists thought what might have happened was that a second squid might have attacked it on its return to the deep, and stole its food.

After the altercation, scientists thought it could have floated back up to warmer water, which decreases blood flow in squid, and causes something close to asphyxiation. In such a state, it wouldn’t have been able to fight the current, which dragged it to shore.


In June 2019, about 100 miles southwest of New Orleans in the Gulf of Mexico, the first giant squid was caught on camera in American waters. Nathan Robinson, who headed the team, found the clip after reviewing 20 hours hours of footage. “My heart felt like exploding,” he told The New York Times.

NOAAA giant squid was caught on camera in the Gulf of Mexico.

Sources: The New York Times, CNN, Smithsonian


The discovery was important, because the giant squid was filmed not far from one of the largest deepwater oil rigs in the world. Sönke Johnsen, a Duke University biology professor, told The Times it dispelled the notion of a monster lurking in remote waters.

Gerald Herbert/APDeep sea oil rig in the Gulf of Mexico.

Sources: The New York Times, CNN, Smithsonian


“You could be out here, and beneath you are giant squid, the things of our wildest imagination! They’re part of our land, they’re part of our country,” Johnsen told The Times.

Danté Fenolio/NOAALeft to right: Nathan Robinson, Sonke Johnsen, Tracey Sutton, Nick Allen, Edie Widder, and Megan McCall gather around to watch the squid video.

Source: The New York Times


For now, the largest recorded giant squid measured up to 43 feet. Their cousin, the colossal squid, can grow up to 45 feet long, but scientists think giant squid can grow up to 66 feet.

Joe Armao / Fairfax Media / GettyRebecca McIntosh and Dr Mark Norman from the Melbourne Museum, measure a giant squid which was caught off Sandy Cape, west coast of Tasmania, 7February 2001

Source: Smithsonian Ocean


Both colossal and giant squid have the largest eyes on the planet, up to 12 inches wide — as big as a basketball. Scientists think it’s because they’re necessary to see clouds of bioluminescence, which let them know when a sperm whale is approaching.

Fernando Camino / Cover / GettyGiant squid ‘Kraken’.

Sources: The New York Times, The Daily Mail, BBC, Smithsonian Ocean


Their sharp beak in the centre of their arms slices its prey into little pieces, which are then ground down by a tongue-like organ covered in teeth. When the giant squid was filmed in 2014, it didn’t shred the bait, as expected, but took small bites, slowly consuming the shrimp, so it didn’t choke.

David Paul, Museum VictoriaGiant squid beak.

Sources: Smithsonian Ocean, BBC


Giant squid have eight arms, and use two long tentacles to seize their prey. But their tentacles don’t have any muscle to constrict prey. So if it comes face to face with a sperm whale, its only option is to flee.

Christophe Archambault / AFP / GettyThis picture taken on March 12, 2019 shows suckers on the tentacles of a giant squid during its restoration process at the Museum d’Histoire Naturelle’s (French National Museum of Natural History) taxidermy workshop in Paris on March 12, 2019.

Sources: Smithsonian Ocean, The Conversation


Clyde Roper, a retired giant squid hunter, told the BBC that if an animal was snared by enough of the suction cups, then it would be impossible to escape.

Mark Norman, Museum VictoriaArchiteuthis tentacle club with suckers giant squid.

Source: BBC


American explorer and underwater filmmaker Scott Cassell told Business Insider that giant squid should be considered an “indicator species,” since they don’t live long, and they’re prolific, occupying every ocean.

Scott Cassell.American explorer and underwater filmmaker Scott Cassell.

“They can offer valuable clues to oceanic health, both in distribution of species they rely on as food and for species that rely on them as food. In a way they’re the centre-point species,” he said. “Sadly, the open sea is a terrible business partner and there is little pay-off for saving our oceans, and huge profits in killing it, overfishing, mining, shipping, and it seems that paradigm won’t change anytime soon.”

NOAA OER/Journey into Midnight/Photo by Danté FenolioNOAA’s squid-hunting vessel R/V Point Sur, heading home.

But much about the giant squid still remains unknown, and because of warming waters and oceans becoming more acidic, the species could die out without humans ever knowing.

Jacquelyn Martin / APCheryl Bright, collection manager for the department of invertebrate zoology, closes a container holding a giant squid that was collected in the Gulf of Mexico.

Source: The New York Times


For now, they remain mysterious, elusive, and hard to catch. As Roper told BBC, due to their size and creepiness, it’s easy to imagine them as violent beasts.

John B. Carnett / Bonnier Corp. / GettyPortrait of Marine Biologist Clyde Roper, with Squid on exhibit in DC.

Source: BBC


“Humans need their monsters,” he said.

William West / AFP / GettyThree-year-old Clea Gadsby inspects a ten metre long giant squid which looks up at her with its giant eye at a display of amazing marine life at the Melbourne Museum, 21 December 2005.

Source: BBC

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