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The Giant Oarfish

Hanging vertically in the sunless depths of the ocean, the Oarfish undulates its dorsal fin to steady itself; a clever trick that makes the fish quite hard for predators to spot.

Common Name
Scientific Name
Giant Oarfish
Regalecus glesne
Oarfish eat by straining various small crustaceans out of the water.
56 feet (17 m)
3,300 feet (1,000 m)
Deep sea in the eastern Atlantic Ocean and Mediterranean.
Mesopelagic Zone

The Giant Oarfish

Hanging near vertically in the sunless depths of the ocean, the Oarfish undulates its crest-like dorsal fin to steady itself; a clever trick, that makes the fish quite hard for predators to spot from above or below. The unnatural light shimmers silver on its scale-less body, and highlights the full length of its seemingly endless tail, and its long tendrils that sense for movement in the water.

Rarely sighted in its natural habitat, Oarfish are a true mystery of the deep. The largest variety, the Giant Oarfish, can exceed 56 feet in length, longer than any other known species of fish, and weigh up to 600 pounds. But despite their leviathan size, their small, toothless mouths allow them to only feed on small fish and squid, as well as plankton. They are harmless to humans, yet something about their unparalleled size can inspire a feeling of terror. Most Oarfish that have been encountered by humans are those that have washed up, dead, on beaches around the world. For reasons as of yet unknown, they come to shallow waters at the end of their life to die, or are beached by strong tides and currents.

What’s peculiar, however, is the fact that almost all of these beached individuals were found to be missing their tail section. A study of a twelve foot giant oarfish that had washed up in 2010 in Sweden found that there were no teeth marks in the snapped of section, and the wound was old. The fish had lived for possibly years after losing the tail section, and in all cases of studied oarfish the rails had all been severed in the last third of the body, in the exact same section. It is
believed to be evidence that oarfish are able to perform an act of autotomy, being the ability
to willingly detach a body part, much like lizards are able to lose their tails when threatened. Why the Oarfish do this, however, remains a mystery.

Another theory that has arisen from the repeated beaching of this fish is that they give warning of imminent earthquakes. Tectonic movement underwater, the precursor to many earthquakes, is thought to kill these weak swimmers, which soon wash up on beaches before the tremors hit. However, when researchers from 2 Japanese universities studied meteorological records and matched earthquakes to oarfish beachings, they found no correlation. With these fish appearing so mysterious and otherworldly, it's no wonder they inspire a sense of superstition in those who see them.