for National Geographic News
For centuries observers have been fascinated and mystified by the majestic spiral tusk grown by the small Arctic whale known as the narwhal.
The extraordinary toothextending up to 9 feet (2.7 meters) and textured like a seashelllong evoked the horn of the mythical unicorn and was once sought by royalty as a magical antidote to poison.
Science shed little light on the narwhal tusk, however, and its purpose remained elusive. That is until now.
Martin Nweeia, a Connecticut-based dentist, is expected today to announce two key discoveries that reveal the tusk's unique structure and provide significant clues to its function. The findings may further explain whale species behavior and recast thinking on other mammalian teeth.
Using cutting-edge technology, Nweeia and his colleagues learned that the narwhal's oversize tooth possesses a rare combination of extraordinary strength and extreme flexibility. It turns out that an 8-foot (2.4-meter) tusk, seemingly rigid, can bend 1 foot (30 centimeters) in any direction.
The team also found compelling evidence that the tusk may be a hydrodynamic sensory organ that contains an extensive nerve system and gathers valuable information for survival in Arctic waters.
Researchers say the tusk's nerve system could detect temperature, pressure, motion, and chemical-solution gradients, such as differences in salinity and water particles that would indicate the presence of certain fish prey.
The tusk also may possess tactile abilities, perhaps allowing narwhals to identify and communicate with one another through tapping.
"There isn't any other tooth like this, not even remotely close," said Nweeia, the research team's principal investigator and a Harvard School of Dental Medicine clinical instructor.
The Connecticut-based dentist is scheduled to announce the findings today at the 16th Biennial Conference on the Biology of Marine Mammals in San Diego.
SOURCES AND RELATED WEB SITES