Martin Nweeia knows more about narwhals than almost anyone in the world. More specifically, he’s probably the world’s foremost expert on narwhal tusks. But Nweeia is only sort-of a marine mammal biologist. He’s actually a practicing dentist and a clinical instructor at the Harvard School of Dental Medicine. This guy knows from teeth. So, while it might seem weird that he studies narwhals, if you think about it, there’s some sense to his in-depth knowledge of these whales’ toothy protuberances. We chatted with Nweeia about why the narwhal tusk is one of the weirdest teeth in the world and what it’s like to wade into the arctic waters of Canada’s Northwest Territories with Inuit guides to get a closer look at the real-life unicorn of the sea.
What exactly is a narwhal?
It’s an arctic whale with an extraordinary tooth.
So, maybe it’s not so strange that you’re a dentist studying a whale...
For everybody else it’s unusual. For me it’s OK. At the heart of things I’m a curious kid. As I went through my dental education I was equally fascinated by people. I had a very strong interest in anthropology that went parallel with my interest in science. These two fields would intersect. For a long time I was interested in dental anthropology, but I happened on the narwhal because I used to give talks and give examples of how teeth would express themselves in nature.
The narwhal seemed like a good example of an unusual tooth. But it didn’t make sense to me. And the more I read about it the less sense it made.
Why doesn’t it make sense?
This is a whale that eats pretty big fish and when you look inside its mouth it has no teeth. If i’m eating large fish, that might require chewing and biting, why give up all those teeth and put all of the energy into growing one giant tusk?
But there are also lots of the little things that don’t make sense. When you think of teeth, on both sides of a mammal's bite you’d expect them to be the same size and have a mirror image morphology or shape. In narwhals it couldn’t be more opposite. It doesn’t even fall within any parameter of any creature ever known on the planet.
If you look at the narwhal’s, its tusk comes out of the left side. When you see photos of them, they angle their body so the tusk appears straight in alignment with the horizontal axis. But if you look at them still, clearly the tusk is coming from the left side. The tooth on the right side often stays embedded in the skull.
You’ve got a tooth on one side that’s between a foot and a foot and a half and on the other side it’s 9 feet. Even in the rare instance when the narwhal has two tusks, the right is usually less in length from the left. The erupted tusk is on the left side or on both sides, or none. Never on the right by itself.