Perhaps the most mysterious and sought-after of all ocean creatures, the giant squid Architeuthis dux was finally captured on video in its natural habitat in July 2012 during an expedition off the coast of the Ogasawara archipelago of Japan. The expedition was sponsored by the Japan Broadcasting Commission (NHK) and by the U.S. Discovery Channel.
The second largest member of the class Cephalopoda — indeed, one of the largest invertebrates that has ever lived — the giant squid can range in length up to 13 meters (43 feet), as measured from the tips of their long feeding tentacles to the edges of the posterior fins on their mantles. (Greater lengths have sometimes been attributed to giant squids, but they were based on measurements of tentacle fragments that may have stretched while drying. Thirteen meters is currently regarded as the largest likely size documented.) Giant squids range throughout all the world’s oceans outside of the polar latitudes, though they favor subtropical and temperate seas. Nevertheless, they are regarded as elusive because they generally live at hard-to-reach depths, down to 1000 meters. More than a dozen species in the genus Architeuthis have been named since naturalists began collecting information on these giant squids in the nineteenth century, but because of confusion and incomplete data, it is possible that many if not all of those creatures are actually forms of Architeuthis dux. See also: Cephalopoda
Giant squids may have helped to inspire legends about sea monsters, such as the kraken of Norse mythology. Systematic scientific study of the creatures did not really begin until the mid-nineteenth century, however, and even then it was mostly limited to speculations based on pieces of its arms recovered from the bellies of captured sperm whales and decomposed bodies washed ashore.
Hundreds of dead specimens have been recovered, including one complete specimen that was caught off the Falkland Islands in 2004. Photographs of live squid are much harder to come by, however. In September 2004, Tsunemi Kubodera of the National Science Museum of Japan and Kyoichi Mori of the Ogasawara Whale Watching Association succeeded in taking still photos of a live adult giant squid in its natural habitat at a depth of 900 meters (3000 feet).
The 2012 expedition succeeded in taking video of Architeuthis by exploiting the knowledge that many organisms in the deep ocean emit light (bioluminescence) to startle would-be predators. The team’s photographers outfitted its underwater remote camera with a bioluminescent lure that resembled the giant squid’s jellyfish prey. This technique proved highly effective at drawing in nearby giant squids. (Bioluminescence in cephalopods can serve a variety of purposes: squids and their relatives often create light to distract predators, attract mates, or camouflage themselves.)
The giant squid should not be confused with the even larger and more massive Mesonychoteuthis hamiltoni, also called the colossal squid. Mesonychoteuthis, first reported in 2005, is known from only a few specimens, most of which have been caught since 2003. It can reach a total length of up to 14 meters (46 feet). However, about 4 meters of this length come from the mantle of Mesonychoteuthis, which is almost twice as large as that of Architeuthis. The giant squid, therefore, has the longer tentacles.
The giant squid is also different from the highly unusual deep-sea squid family called the Magnapinnidae. The first members of this group were identified in 1998, and the first video of one in the wild was taken in 2003. These squids are unusual in that all 10 of their limbs seem to be identical; other squids typically have two long tentacles and eight shorter arms with distinct functions. Magnapinna squids are larger than most squid but much smaller than Architeuthis. They range in total length up to about 8 meters (25 feet).