How Big Is a Giant Squid? Length, Eyes and Records

Giant squid size at a glance

The giant squid (Architeuthis dux) is one of the longest invertebrates on Earth. Hundreds of specimens have now been recorded, about 700 by the 2010s, so its real size is fairly well known.

The mantle figure comes from the study of 130 specimens and of beaks found in sperm whale stomachs; no mantle longer than about 2.25 m (7.4 ft) has been reliably measured.

Why the tentacles make up most of the length

A giant squid has eight arms and two much longer feeding tentacles. In a large squid, the mantle, head and arms together may measure about 4–5 m (13–16 ft), while the two tentacles add several more meters. In 2004, when a giant squid was photographed attacking a baited line off Japan, it escaped by tearing off a tentacle that was 5.5 m (18 ft) long by itself.

The tentacles are thin, muscular and highly elastic. In life they are usually held close to the body and shot out only to grab prey. After death, they relax and can stretch a long way if the squid is dragged, hung up or pulled straight for measuring. Because so much of the length is in these slender limbs, a giant squid is much lighter than its length suggests.

Why were old records so exaggerated?

Giant squid of 18 m (60 ft) or more appear in many books, but squid specialists no longer accept them. Clyde Roper of the Smithsonian, who examined around 100 specimens, said there were no confirmed records longer than about 14 m (45 ft) and that most specimens are 7.6–10.7 m (25–35 ft). The New Zealand expert Steve O’Shea has argued that the giant figures were reached by stretching the tentacles like elastic bands.

Several famous records illustrate the problem:

• Thimble Tickle, 1878: a squid stranded in Newfoundland was reported at about 16.8 m (55 ft) in total. It is still often called the largest ever, but it was not measured to modern standards.
• New Zealand, 1887: a squid reported at 16.8 m (55 ft) had extraordinarily long tentacles for its body size and was at first paced out, so experts still debate how accurate the figure is.
• The 19 m squid: a widely repeated 19 m (62 ft) specimen from a sperm whale’s stomach turned out to be a misprint for 9 m (30 ft).

A 2016 statistical study by Charles Paxton argued that giant squid of around 20 m (66 ft) might exist, but other experts have questioned the reliability of the old records on which it relied. For now, no squid that long has been measured.

Female vs male size

Giant squid show clear sexual dimorphism: females grow bigger and heavier than males. The largest females are estimated at about 12–13 m (39–43 ft) and 275 kg (606 lb), while males are thought to reach about 10 m (33 ft) and 150 kg (330 lb). Males also mature at a smaller size than females. Mature males can be recognized by an extremely long penis, more than 90 cm (3 ft) long, which extends from inside the mantle.

How big are a giant squid’s eyes?

The eyes are perhaps the most remarkable thing about the giant squid’s size. They reach at least 27 cm (11 in) across, roughly the size of a dinner plate, with a pupil about 9 cm (3.5 in) wide. A human eye is about 2.5 cm (1 in) across.

Only the colossal squid of the Antarctic has eyes of similar or greater size, and among extinct animals only the ichthyosaurs, marine reptiles of the dinosaur age, are known to have had larger ones. A 2012 study suggested that such huge eyes help the squid spot sperm whales, whose movements make glowing plankton light up, at distances of more than 120 m (390 ft) in the dark.

How does it compare with the colossal squid and the sperm whale?

The giant squid is probably the longest squid, but not the heaviest. The colossal squid is shorter, with the largest measured specimen about 4.2 m (14 ft) long after thawing, yet it weighed about 495 kg (1,091 lb), nearly twice the estimated maximum for a giant squid. The differences in body shape, hooks and range are covered in giant squid vs colossal squid.

Neither squid comes close to the sperm whale, its main predator. Male sperm whales average about 16 m (52 ft) long and weigh tens of tonnes, so a giant squid weighing a few hundred kilograms is simply prey. Among the largest animals in the world, the giant squid stands out not for bulk but for its length and its eyes.

Famous giant squid you can see

Several well-preserved giant squid are on public display. The best known in Europe is “Archie,” an 8.62 m (28.3 ft) squid caught by a fishing trawler off the Falkland Islands in 2004 and shown at the Natural History Museum in London since 2006. The Smithsonian’s National Museum of Natural History in Washington, D.C., displays giant squid in its Sant Ocean Hall, and many museums and aquariums in Japan show specimens found in the Sea of Japan, where 57 giant squid were recorded in just 15 months in 2014–2015.

None of these animals is anything like the island-sized monsters of legend. Where those stories came from is explained in is the kraken real?