The Narwhal Tooth: Solving the Mystery of Nature’s Most Intriguing Tooth

Connecticut State Dental Association

The narwhal tooth has long fascinat- ed sea explorers, scientists and aristocracy. The legendary spiraled tusk has wound its way into the books of scientific rarities and mythical legends. Researchers have proposed myriad theories to explain a tooth that extends 6-10 feet from the upper jaw of this arctic whale. Yet, they have come no closer to an understanding of its evolution and purpose.

In May, 2003, Sharon dentist and explorer Dr. Martin Nweeia will travel 2,000 miles north to the northern tip of Baffin Island gathering information that he hopes will unlock one of nature's most intriguing mysteries.

Awarded the prestigious "flag" of the Explorers Club World Center for Exploration, Martin will venture miles out on an ice floe escorted by an Inuit hunter and gather information from observation and harvested whale.

Having already returned from a preliminary investigation in 2002, Nweeia has become well used to the temperatures which fall below minus 20 degrees Celsius wind storms causing white out conditions, and the usual arctic camp site visitor, the polar bear.

Throughout history, the narwhal tooth has inspired legend and lore. So prized was the fabled tooth of the unicorn that Queen Elizabeth in the 16th century paid 10,000 pounds for one, equivalent to the cost of an entire castle. The tooth is revered by many cultures around the world. For example, two crossed narwhal tusks adorn the entrance to the Korninkaku Palace in Japan and multiple tusks comprise the frame of the Danish throne.  Scientists, equally intrigued, support author and explorer Ivan T. Sanderson's comment on the narwhal as being ".the most extraordinary of all living mammals." Narwhal are distinguished as being nature's most unusual example of sexual dimorphism in teeth.

Males almost always exhibit a left tooth protruding 7-10 feet through the upper lip while females seldom (1 in 500) exhibit the trait. Narwhal teeth also represent one of the most dramatic examples of directional asymmetry in nature. The left tooth of a male can extend to 10 feet while the right tooth measures less than one foot. Occasionally a male can have two protruding elongated teeth. In such cases, both teeth exhibit a counter clockwise spiral, a growth pattern whose function and purpose has eluded scientific scrutiny. A true morphologic counterpart would be a mirror image with the spiral in a clockwise direction. The asymmetry is thus evident in both size and form.

Why does one mammal exhibit such an unusual array of dental traits, and how can they be explained? Martin has assembled a team of investigators from Harvard School of Dental Medicine where he teaches as a clinical instructor, The Forsyth Institute, The Museum of Comparative Zoology at Harvard and the Smithsonian Institution Museum of Natural History where the Connecticut dentist resided as graduate research fellow while in den- tal school. "Only by integrating the information and perception of people with diverse viewpoints, will we dis- cover the purpose of this incredible tooth," comments the CSDA member

Already, Nweeia has begun travels to Museums with skeletal collections of narwhal including those in Washington, D.C., Boston, New York, Ottawa, Copenhagen and Nuuk in Greenalnd. He will compile pho- tographic records as well as three dimensional scans, including CAT scans and T-Scans, a high resolution laser surface scanner recently devel- oped by Steinbichler Optotechnik.

This latter scan has only been used to monitor surface imperfections on NASA space shuttle parts and assemble a dinosaur at the Field Museum in Chicago. Now the company feels that the narwhal tooth should join this illustrious list.

The knowledge of Inuit hunters and elders will also add perspective to the scientific information gathered. For decades, narwhal has been hunted and observed by the Inuit who pass down and preserve their observations amongst each other. Since they spend an inordinate amount of time around these whales, their sightings and stories may provide further insight into the data collected. For example, observations by Inuit hunters may shed light on "tusking" a behavior where males rub tusks with each other. They may also add need- ed information to understand the cause of broken tusks.

For further information on The Narwhal Tooth Expedition log on to www.hsdm.harvard.edu and click on the research links and resources or go to the expedition web site at www.nar- whal.org. .