The nature of the narwhal: ‘The one that is good at curving itself to the sky’ | Helen Sullivan
There are some animals about which it is easy to forget the fact that they have teeth, so that every time they flash their grins, it is as though you are seeing a new animal. Dogs, cats of all kinds, sharks and crocodiles are not among these. Horses, rabbits, fish and geese live toothless in my mind.
Narwhals are among the actually toothless, if you discount their tusks. Inside their mouths, which are shaped in a permanently sweet smile, there are no teeth as we understand teeth to be.
But the males have a long, unicorn-like projection protruding – just off centre – from what might be described as their upper lip. I find them quite festive, like ornaments that should be hung on a Christmas tree. Maybe it’s their wintry, icicle-like tusk. I try to forget that this tusk is a tooth.
In Moby-Dick, Ishmael describes the narwhal as having: “A very picturesque, leopard-like look, being of a milk-white ground colour, dotted with round and oblong spots of black.” He describes the “peculiar horn”, because it is not in the middle, as “giving its owner something analogous to the aspect of a clumsy left-handed man.”
Nobody knows for sure what the beautiful tusk is for.
“It is striking when you think that this animal decided to take all of its tooth-producing energy and put it into one thing [a tusk] that sticks out nine feet into the ocean,” Martin Nweeia, a Harvard dentist told the Smithsonian, where he is a member of the Department of Vertebrate Zoology. “With the amount of energy that it takes to produce that one tusk it could easily have 30 to 40 teeth in its mouth doing other things.”
“Tooth-producing energy”; the idea of teeth “doing other things”. It is all quite a lot to chew on.
In 2014, Nweeia developed a new theory: the tooth is sensitive, a bit like our teeth when we drink ice water. But because of its spiral shape, it seems to be designed to expose the narwhal tusk to the water, rather than protect them. Nweeia believes that the tusks can sense the salinity of water, which helps them to tell whether icebergs are melting, diluting the sea, or forming, which makes it more salty. This tells them whether they need to leave in order to avoid being trapped in the ice.