We got to thinking about narwhals this week as we came across a new NSF grant awarded to Martin Nweeia of Harvard University. Nweeia has been working with Inuit colleagues in Canada to understand the purpose and function of the narwhal’s spiral tusk, and his new grant supports continuing efforts. Extremely shy inhabitants of the pack ice off western Greenland and parts of Canada, the narwhal has largely remained an enigma, its appearance a wheel on which to spin legends.
But the “unicorn of the sea” is actually a tooth-bearing whale. The tusk is one of the narwhal’s two teeth; it erupts through the whale’s mouth and can grow to more than 8 feet long. Though some females will grow the tusk, it is mostly found on males. Why? What adaptive pressures could make this whale sprout a giant tusk?
Nweeia’s team has been collecting information to answer that question. Through interviews with Inuit elders in Pond Inlet, Baffin Island, Canada, and in northwestern Greenland—elders who have observed narwhal behavior and tusk function for their entire lives--Nweeia analyzes hypotheses related to tusk function. For example, some think that the narwhal tusk is for show, like a male lion’s mane, or a peacock’s tail. In a similar vein, others suggest male narwhals use the tusk for defense, or to fight for dominance during mating season, much as elk bump horns in autumn. Still others postulate that the tusk helps the narwhal keep breathing holes open in the frozen-over sea or to skewer prey hiding under the ice.
Nweeia’s own study of tusk structure, coupled with direct observations recorded in interviews with Inuit, suggests a more delicate, sensory function. The tusk, enervated along its entire length and therefore likely to be highly sensitive, may actually function as an environment-monitoring apparatus. It may be able to detect water properties—salinity, pressure and temperature, for example--that could help male narwhals select the best waters for breeding, or know when water conditions may cause the pack ice to freeze up around them if they remain.
The Nweeia team has a Web site, http://www.narwhal.org/index.html, where would-be armchair narwhal experts can brush up on everything narwhal: biology, mythology, Inuit traditional knowledge and more.
Meanwhile, National Public Radio this week aired a series on narwhal research in Greenland led by Kristin Laidre of the University of Washington. Journalist Nell Greenfieldboyce joined Laidre, who, with the help of Inuit colleagues, is trying to catch glimpses of the elusive mammal’s underwater world.
Laidre’s research involves placing small satellite tracking devices on the backs of narwhals. Information collected can help scientists understand narwhal movement patterns and diving depth, for example. But fitting these shy creatures with the devices is no easy task, as the NPR piece shows clearly. (For two weeks Laidre watched as narwhals would flirt with the nets she had cast only to steer clear of them in the end.) Without assistance from her Inuit colleagues, who helped the researcher attach trackers via specially treated harpoon, Laidre would not have captured even one whale in her nets this summer.
We also found this National Geographic feature on the narwhal, from 2007. Author Paul Nicklen grew up on Baffin Island. He admits in the field notes section of the piece that he struggled to balance his appreciation for traditional Inuit practices and his sense of loyalty to his friends, the hunters, against his criticism of some modern hunting practices he witnessed. A riveting story with abundant pictures and other media make this an appealing site for narwhal fans.