Marine biology mystery solved

Harvard School of Dental Medicine (HSDM) researcher Martin Nweeia has just answered a marine science question that had eluded the scientific community for hundreds of years: why does the narwhal, or "unicorn," whale have an 8-foot-long tooth emerging from its head, and what is its function? Nweeia, a clinical instructor in restorative dentistry and biomaterials sciences at HSDM, will be presenting his conclusions at the 16th Biennial Conference on the Biology of Marine Mammals in San Diego.

The narwhal has a tooth, or tusk, that emerges from the left side of the upper jaw and is an evolutionary mystery that defies many of the known principles of mammalian teeth. The tooth's unique spiral, the degree of its asymmetry to the left side, and its odd distribution among most males and some females are all unique expressions of teeth in mammals. The narwhal is usually 13 to 15 feet in length and weighs between 2,200 and 3,500 pounds. Its natural habitat is the Atlantic portion of the Arctic Ocean, concentrating in the Canadian High Arctic: Baffin Bay, Davis Strait, and northern Hudson Bay. It is also found in fewer numbers in the Greenland Sea, extending to Svalbard to Severnaya Zemlya off the coast of Russia.

The narwhal has a tooth, or tusk, that emerges from the left side of the upper jaw and is an evolutionary mystery that defies many of the known principles of mammalian teeth. The tooth's unique spiral, the degree of its asymmetry to the left side, and its odd distribution among most males and some females are all unique expressions of teeth in mammals. The narwhal is usually 13 to 15 feet in length and weighs between 2,200 and 3,500 pounds. Its natural habitat is the Atlantic portion of the Arctic Ocean, concentrating in the Canadian High Arctic: Baffin Bay, Davis Strait, and northern Hudson Bay. It is also found in fewer numbers in the Greenland Sea, extending to Svalbard to Severnaya Zemlya off the coast of Russia.