Narwhals: the truth about the unicorn of the sea

You have almost certainly met the narwhal before, even if you’ve never seen one. It arrives in the imagination wearing a horn, a single ivory spike set in the middle of its brow, half whale and half heraldry. For centuries people took it for a fable, a sea-going cousin of the unicorn, and the name stuck so firmly that we still call it the unicorn of the sea. The trouble is that almost everything the name implies is wrong. The animal is entirely real, and it’s swimming through the cold dark of the high Arctic while the legend does its work above the surface. Set the myth aside and what’s left is stranger, and better.

The horn that is a tooth

Start with the spike, because that’s where the misunderstanding lives. What juts from a narwhal isn’t a horn at all but a tooth, an elongated left canine that pushes straight out through the upper lip and keeps growing. It spirals as it goes, always anticlockwise, and it can reach somewhere around two to three metres. A tooth as long as a small boat, worn on the face, turning the same way on every animal that grows one.

Usually it’s only the males who carry a tusk. Now and then a female grows one too, and occasionally an animal sports two, a matched pair of spiralling teeth. So the tidy image of the lone horned unicorn is really a portrait of one sex, most of the time, with enough exceptions to keep biologists interested.

What the tusk is actually for

Here the story turns from odd to genuinely puzzling, because nobody can yet tell you with certainty what the tusk is for. That’s honestly where the science sits.

What we do know is that the tusk isn’t the dead ivory it resembles. It’s a living sensory organ, threaded with nerve endings that run through the tooth and connect it to the sea around it. Researchers have shown that it responds to changes in the water, the tooth in effect tasting or sensing its surroundings. That alone upends the folklore. The unicorn’s magic wand turns out to be, of all things, a sense organ worn on the outside of the body.

Why an animal would carry such a thing is where the debate begins. Some researchers argue the tusk is chiefly a display trait, a piece of showmanship in which a bigger tusk signals a bigger, fitter male to rivals and females alike, much the way antlers work on land. Others point to that rich sensory wiring and argue the tooth earns its keep by reading the water. Both could be right at once. A tooth that tastes the sea is not stopped from also being the thing a female notices, or a rival measures himself against, in a crowded summer bay.

There’s one thing the tusk has been caught doing on camera. Narwhals have been filmed using it to tap and stun small fish before eating them, first recorded by drone in Arctic Canada in 2017 and seen again in drone studies since. It’s an unexpected sight, a two-metre tooth used with the delicacy of a fishing rod. Whether that’s its main purpose or simply one clever use an animal found for the tool it already had, no one can yet say.

How the legend was made and sold

The unicorn part of the name isn’t poetic invention. It’s trade history. In medieval and Renaissance Europe, narwhal tusks travelled south from the Arctic and were sold as unicorn horns, and they fetched extraordinary sums. A horn was said to reveal or neutralise poison, which made it precious to nervous royalty, and pieces are reported to have been valued at figures that sound absurd today. The narwhals themselves stayed out of sight in the far north, so the spiral tooth could stand in for a creature no European had ever watched swim. The myth was a supply chain. Somewhere in the Arctic a whale grew a tooth, and somewhere in a European court a king paid a fortune for a unicorn.

A creature of the ice, and of distance

Where the narwhal actually lives explains both why it stayed mythical for so long and why it’s so seldom seen even now. This is a medium-sized toothed whale of the high Arctic, found mainly around Arctic Canada and Greenland and only occasionally near Svalbard and Russia. Many spend the winter months beneath the pack ice of Baffin Bay and Davis Strait, surfacing to breathe at cracks and leads in a frozen ceiling. They’re serious divers, reaching around 1,200 metres on a routine descent, with dives beyond 1,800 metres on record and the animal staying down for something like twenty-five minutes before returning to the light. They live among the sea ice the whole year through.

That way of life should shape your expectations honestly. Narwhals are elusive, and no voyage can promise you one. They keep to ice edges and deep water in some of the least visited waters on the planet, and a sighting, when it comes, is a matter of luck and quiet and being in exactly the right lead at the right hour. It’s a long way to travel on the chance of it, so it’s better to think of the narwhal as an animal to understand than one to expect.

They aren’t, at least for now, a species in trouble. There are well over 100,000 of them, and current assessments place them as not at risk, though the loss of sea ice and the slow arrival of ship traffic in the north are watched closely. Inuit communities in Canada and Greenland hunt them under managed quotas, as they long have, and the narwhal remains a traditional food as much as a legend.

Somewhere under the pack ice of Baffin Bay a pale whale is turning in the dark, a spiralling tooth reading the sea ahead of it, indifferent to the fortune its cousins once fetched at court.