Kraken are mythical sea monsters of gargantuan size, said to have dwelt off the coasts of Norway and Iceland. The sheer size and fearsome appearance attributed to the beasts have made them common ocean-dwelling monsters in various fictional works. The legend may actually have originated from sightings of real giant squid that are variously estimated to grow to 13–15 m (40–50 ft) in length, including the tentacles. These creatures normally live at great depths, but have been sighted at the surface and reportedly have “attacked” ships.

Kraken is the definite article form of krake, a Scandinavian word designating an unhealthy animal, or something twisted. In modern German, Krake (plural and declined singular: Kraken) means octopus, but can also refer to the legendary Kraken.

Even though the name kraken never appears in the Norse sagas, there are similar sea monsters, the hafgufa and lyngbakr, both described in Örvar-Odds saga as a giant spider-creature. Carolus Linnaeus included kraken as cephalopods with the scientific name Microcosmus in the first edition of his Systema Naturae (1735), a taxonomic classification of living organisms, but excluded the animal in later editions. Kraken were also extensively described

by Erik Pontoppidan, bishop of Bergen, in his “Natural History of Norway” (Copenhagen, 1752–3). Early accounts, including Pontoppidan’s, describe the kraken as an animal “the size of a floating island” whose real danger for sailors was not the creature itself, but the whirlpool it created after quickly descending back into the ocean. However, Pontoppidan also described the destructive potential of the giant beast: “It is said that if it grabbed the largest warship, it could manage to pull it down to the bottom of the ocean” (Sjögren, 1980). Kraken were always distinct from sea serpents, also common in Scandinavian lore (Jörmungandr for instance).

According to Pontoppidan, Norwegian fishermen often took the risk of trying to fish over kraken, since the catch was so good. If a fisherman had an unusually good catch, they used to say to each other, “You must have fished on Kraken.” Pontoppidan also claimed that the monster was sometimes mistaken for an island, and that some maps that included islands that were only sometimes visible were actually indicating kraken. Pontoppidan also proposed that a young specimen of the monster once died and was washed ashore at Alstahaug (Bengt Sjögren, 1980).

Since the late 18th century, kraken have been depicted in a number of ways, primarily as large octopus-like creatures, and it has often been alleged that Pontoppidan’s kraken might have been based on sailors’ observations of the giant squid. In the earliest descriptions, however, the creatures were more crab- like than octopus-like, and generally possessed traits that are associated with large whales rather than with giant squid. Some traits of kraken resemble undersea volcanic activity occurring in the Iceland region, including bubbles of water; sudden, dangerous currents; and appearance of new islets.

In 1802, the French malacologist Pierre Dénys de Montfort recognized the existence of two kinds of giant octopus in Histoire Naturelle Générale et Particulière des Mollusques, an encyclopedic description of mollusks. Montfort claimed that the first type, the kraken octopus, had been described by Norwegian sailors and American whalers, as well as ancient writers such as Pliny the Elder. The much larger second type, the colossal octopus (depicted in the above image), was reported to have attacked a sailing vessel from Saint-Malo, off the coast of Angola.

Montfort later dared more sensational claims. He proposed that ten British warships that had mysteriously disappeared one night in 1782 must have been attacked and sunk by giant octopuses. Unfortunately for Montfort, the British knew what had happened to the ships, resulting in a disgraceful revelation for Montfort. Pierre Dénys de Montfort’s career never recovered and he died starving and poor in Paris around 1820 (Sjögren, 1980). In defense of Pierre Dénys de Montfort, it should be noted that many of his sources for the “kraken octopus” probably described the very real giant squid, Archeteuthis, proven to exist in 1857.

In 1830, possibly aware of Pierre Dénys de Montfort’s work, Alfred Tennyson published his popular poem “The Kraken” (essentially an irregular sonnet), which disseminated Kraken in English with its long-standing superfluous the. The poem, in its last three lines, also bears similarities to the legend of Leviathan, a sea monster, who shall rise to the surface at the end of days.