Illustration of a giant squid
Image credit: A.E. Verrill (c. 1880)

One of the most recognizable deep-sea creatures in pop culture and folklore, the giant squid (Architeuthis dux) has captured the human imagination for centuries. Aristotle, the famous Greek philosopher, wrote a description of the squid as early as 350 BCE, calling it teuthos. Known also as the kraken, the squid earns its name due to its enormous size: Scientists estimate that female giant squids can grow up to 43 feet (13 m) long! Don’t confuse the giant squid with the slightly larger colossal squid (Mesonychoteuthis hamiltoni); they’re two completely different species, although they both belong to the order Oegopsida.

Many could easily point out a giant squid due to its unique appearance. They have extremely large eyes, the largest of any animal with a diameter of up to 10 inches (25 cm). For perspective, that is about the size of a human head! There’s a reason why these eyes are so big; as creatures of the deep, the squid needs massive eyes to see in the dark. Like other species of squid, they have 8 arms and 2 tentacles. A giant squid’s arms have rows of suckers, and their tentacles, which they use to hunt, are longer than the rest of their body. Females are generally larger than males, with females reaching lengths of up to 43 feet (13 m) and males 33 ft (10 m).

Despite being such an easily recognizable creature, we actually don’t know too much about the giant squid since it lives so far down beneath the ocean’s surface. Up until 2013, scientists couldn’t come to a consensus on how many species of giant squid there actually are. Now, however, evidence seems to support that there is likely only one species of giant squid.

There are roughly 500 species of squid, and they all belong to the class Cephalopoda (about 1,000 species) and the phylum Mollusca (roughly 200,000 species). Cephalopods, which include octopuses as well as squid, have three hearts and well-developed brains. Creatures in this class live exclusively in salt water, so don’t expect to find any giant squid in lakes outside of Hogwarts. Cephalopods are ancient; scientists have found fossils that date back 500 million years.

As deep-sea creatures, giant squids are notoriously difficult to study. Scientists have learned about the squids mostly through examining washed-up specimens or those caught in commercial fishermen’s nets. Scientists have even followed sperm whales (Physeter macrocephalus), which are known predators of the giant squid, in an attempt to learn more about this elusive creature. In September 2004, however, some researchers struck metaphorical gold; they were able to film a giant squid feeding at depth of 2952.8 feet (900 m) off the coast of Japan.

Scientists still know little about the reproductive habits of this creature, although the general consensus is that they reach sexual maturity at three years of age. Architeuthis dux doesn’t have a hectocotylus, or a modified arm used for transferring sperm, so scientists aren’t even sure about how the male fertilizes a female’s eggs. They do know, however, that the female can lay over 11 pounds (5 kg) of eggs.

Two scientists inspect the remains of a giant squid
Image credit: NTNU University Museum

How long does the giant squid live?

Cephalopods, in general, have short lives. The giant squid is no exception, with scientists believing it lives only five years, dying after reproducing once. The cephalopod reproductive strategy is to grow quickly and reproduce once.

How long are giant squid tentacles?

Giant squid have eight arms and two tentacles, the latter of which can make up two-thirds of the squid’s length.

How much does the giant squid weigh?

The largest squid found is believed to have weighed almost a ton.