Instructor: Whales Tender to the Tusk

Following four trips to the Arctic Circle and close to five years of research on the narwhal, Martin T. Nweeia, a clinical instructor at the Harvard School of Dental Medicine, has discovered new information about the sensory abilities of the whale’s tusk.

Nweeia discovered that the narwhal tusk is equipped with 10 million sensory endings that have the capability to detect changes in water temperature, pressure, osmotic gradients, and motion.

According to Nweeia’s website, www.narwhal.org, the tusk is actually a tooth, shaped like a spiraled rod, which projects out of the male’s upper jaw through its lips and ranges six to nine feet in length. According to the site, it is very rare for a female to have a tusk.

William Fitzhugh—director of The Arctic Studies Center (ASC), which is part of the Smithsonian Institution—explained the significance of Nweeia’s findings. He noted that, since salt water freezes four degrees lower than fresh water, the narwhal’s ability to detect salinity in the water would allow it to stay in waters that are less likely to freeze.

“One thing this is showing is how little we know about a lot of creatures, especially those in the north,” said Fitzhugh. “Closer work with the Inuit will bring about more results [on the narwhal’s tusk].”

The Inuits, an indigenous people living in the Arctic, are very familiar with the animals.

Nweeia, who also has a full-time dental practice in Connecticut, said he pursued research of the narwhal’s tusk “out of pure childlike curiosity.”

During his first week-long trip to the Arctic, Nweeia spent a week alone with an Inuit guide. On his second trip to the Arctic, he brought his friend and experienced photographer, Joseph Meehan. Teams of scientists from Canada, Denmark, and the United States accompanied him on his last two trips.

On the fourth and final expedition this past summer, Meehan said he witnessed one of the most interesting uses the narwhals find for their tusks.

“I saw tusking happen, once,” he said. “The tusks rose out of the water in a 45-degree angle and then they gently rubbed against each other. It only lasted a few seconds.”

Nweeia said the narwhals feel a definite sensation in tusking and it is a “good way of cleaning their teeth.”

“It happens often,” he said. “It doesn’t only happen above water.”

Funding for the project came from a variety of sources, including the Smithsonian Institution, the Museum of Comparative Zoology at Harvard, and Harvard School of Dental Medicine, according to Nweeia.

The ASC provided organizational help, as well as some research grants and much information about the Inuits, said Fitzhugh.