You’d think that narwhals couldn’t be more enchanting. These elusive, ice-dodging, deep-diving whales have 10-foot snaggletoothed tusks, and they see with sound.

But then there’s the narwhal of east Greenland. It’s kind of the narwhal of narwhals.

“Because they’re so hard to access, we honestly hardly knew anything,” said Susanna Blackwell, who studies the effects of human sounds on marine mammals for Greeneridge Sciences. “It’s an animal that’s been hidden from civilization for an awful long time.”

Their genes are only slightly different than their western cousins. And since glaciers separated them some 10,000 years ago, this smaller population of about 6,000 narwhals, has lived relatively free from human contact amid sharp cliffs and mile-wide glaciers that break into huge, bobbing icebergs.

But as the ocean warms, ice caps melt and summers get longer in the Arctic, the once inaccessible habitat of east Greenland narwhals is opening up to scientists — as well as cruise ships and prospectors interested in minerals or offshore drilling. And because toothed whales like narwhals use sounds to orient themselves, Dr. Blackwell worries this potential activity will disturb the narwhal’s acoustic way of life.