Its eye is the size of your head.
It lives more than 3,000 feet deep in oceans around the world and is 30-feet long, yet it lacks a backbone. With eight arms and two tentacles, it is the origin of the myth of the Kraken.
Its only predator is the sperm whale, whose numerous battle scars show evidence of this strange, epic battle between mammal and mollusk.
I speak of the giant squid. Architeuthis. The only invertebrate larger is the colossal squid, Mesonychoteuthis, that lives in the frigid depths of the Antarctic Ocean and about which little is known. But stay tuned. The deep sea is a frontier.
Teuthologist (that's squid scientist for the rest of us) Rui Rosa of the University of Lisbon says the colossal squid "weighs half a ton, with hooks in its tentacles." But is the colossal squid the stuff of nightmares? Not really, he says. His findings show it's more like a giant blob.
These squids, both giant and colossal, have evolved through "abyssal gigantism" —the tendency of deep water creatures to get much larger than their shallow water cousins. Think of the Alaskan king crab, a single leg of which can feed a family, compared to the Chesapeake blue crab, which can take a bushel.
This gigantism also applies to the squid's nervous system. Most invertebrate nerve cells are visible only under a microscope, but all squids have a large nerve cell—the squid giant axon—that is as thick as the diameter of a felt-tip pen and extends the entire length of its body. This giant axonal network enables a terrifically fast startle-escape response. It can contract its mantle and jet-propulse out of the way of danger.
Though adept at self-preservation, the giant squid is also a hunter. It can whip-crack its long tentacles like a net full of deadly, razor-sharp suckers. It can be cannibalistic. Scientists believe some may even attack and eat small whales.
But how does it find food to eat in the dark abyss? Incredibly, in a habitat that's always midnight black, the giant squid hunts by sight.
With its gigantic eye, it can detect the faintest glimmers of bioluminescent light. Bioluminescence is chemical light, generated by plankton, jellies, anglerfish, and many other creatures who signal for food and mates, much like deep-sea fireflies.
American marine biologist Dr. Edie Widder used bioluminescence to her advantage when she recently captured on film, for the first time ever, an adult giant squid.
She and her team designed a biomimic lure, a blue pinwheel of light, identical to the distress signal of a common deep-sea jellyfish, specifically to attract the squid.
It worked. The giant squid, the stuff of sailors' legends, zoomed into view, sinuous, metallic-golden, making history in both filmmaking and marine science. In the cockpit of their submersible, the scientists' elation can clearly be heard—like kids at Christmas!