What Connects A Narwhale Tusk And A Dentist?

it might help to know that the tusk is actually a tooth, 

photograph Glenn Williams, which is what got dentist and researcher/explorer Martin Nweeia interested in the narwhale, from the article:

‘In 2005, we released work suggesting the tusk is a sensory organ. Our team found that over about an eight-foot section of tusk there were about 10 million sensory connections to its ocean environment, through dentinal tubules. All mammals have dentinal tubules — the difference with narwhal is that they’re open, from the inside nerve to the outside of the tooth. In people, these tubules are below our gum line. People who have bone recession or receding gums can expose them, and this makes them sensitive to cold foods. So having the tubules open is unusual, especially for an animal living in the cold Arctic environment — it’s the last place you would expect to see this’.

photograph Clint Wright, above Martin Nweeia and a field team with Fisheries and Oceans Canada assess narwhal heart rate when the animal’s tusk is exposed to salty or fresh water, again from the article:

'The story was that this gigantic tusk was just for social hierarchy, like a lion’s mane or a peacock tail. The more I read, the less sense this made. Just to get the best girl of the lot? It doesn’t seem plausible to me. This animal has gone through an enormous sacrifice to create this thing. I thought, this animal deserves a better story. By 2014, I was finally able to prove that this tusk in a living animal could sense its environment. I was working with Fisheries and Oceans Canada: We would capture a whale in a net and bring him to shore for a half an hour to be tagged. I would conduct my study during that time. I developed a plexiglass gasket that I could attach over a small section of tusk and fill with salty or fresh water. Then I would measure the whale’s brain and heart activity. The electrocardiogram was most accurate. I tested just six whales but had thousands of data points. And we showed that salty water led to a higher heart rate. Fresh water, a slower rate. It took me a long time to work this out'.

 photograph Joseph Meehan for Narwhale Research, hunter and search-and-rescue expert David Angnatsiak of Pond Inlet, Baffin Island, was Nweeia’s guide and friend, it is a fascinating article about an animal that we still know so little about, but Martin Nweeia continued his studies with this creature and with help from the Inuit people has added to our knowledge of this fascinating mammal, the full story is here, and intriguingly he makes mention of another whale he would like to study,

‘the strap-toothed whale. He is my second favorite whale. These guys are found off New Zealand and Australia. They have two tusks that erupt from their lower jaw, wrap around their upper jaw and can restrict them from opening their mouths. Where did that come from? I mean, how counterintuitive can you possibly get?’

 hopefully Nweeia will pen another article on them in the future, a little about the author, he has a dental surgery practice based in Sharon, Connecticut, he lectures at Harvard’s School of Dental Medicine and holds a global fellow position at the Polar Institute at the Wilson Centre. He is also a research associate at the Arctic Studies Centre of the Smithsonian Institution and at the Canadian Museum of Nature, and a member of the Zoonomia Consortium of Harvard/MIT.