While the plight of the polar bear deservedly gets most of the attention in Arctic-warming scenarios, the narwhal is even more at risk, according to a study of marine mammals’ vulnerability. Scientists from three countries identified risk factors for 11 mammals that live in the Arctic year-round.  

The narwhal is a pale-colored porpoise with a long spiral tusk found in Arctic coastal waters. It dives about 6,000 feet to feed on halibut and lives in parts of the Arctic that are 99 percent heavy ice. According to the lead researcher, Kristin Laidre, from the University of Washington, the narwhal’s food needs and habitat make it more vulnerable than even the polar bear. While bears can adapt somewhat to the changing seas, the narwhal cannot.

The study, Quantifying the Sensitivity of Arctic Marine Mammals to Climate-Induced Habitat Change, was published in Ecological Applications, a journal of the Ecological Society of America. The researchers identified three types of sensitivity to climate-changes in habitat, including limited distribution and specialization in feeding, seasonal dependence on ice, and reliance on sea ice for access to prey and avoiding predators. After the narwhal and the polar bear, the most at risk mammals were the hooded seal, bowhead whale and walrus.

The narwhal has been called the unicorn of the sea for its eight-foot long, tusk-like tooth that grows out of the male’s upper lip.