Narwhals breathing in a lead at the surface. Photo by Glenn Williams, courtesy of Wikimedia Commons.

The Twin Otter plane that carries Kristin Laidre two hundred kilometers off the west coast of Greenland has Plexiglass bubble windows installed on both sides of the cabin. When Laidre peers through the glass, she can see the blank expanses of ice and snow covering the ocean’s surface in all directions, including directly beneath her.

That’s where Laidre, a marine mammal biologist at the University of Washington’s Polar Science Center, has trained her eyes to look—down at the cracks of open water that blemish the otherwise pristine fields of ice. It’s often tedious work, playing “I spy a narwhal,” but when she catches sight of the whale, it makes the waiting worthwhile.

Kristin Laidre, a marine mammal biologist at the University of Washington’s Polar Science Center. Credit: Erik W. Born.

“It’s amazing,” she says. “There is nothing except extremely dense ice in the winter. You look down, and there will be just one crack or open area in the ice, and you’ll see a narwhal coming up for air.”

Even though Laidre has taken more than thirty trips to the Arctic, many of them to study the mysterious narwhal, the sight of the creature in its native environment still awes her.

“It’s still just unbelievable that they can live in such an extreme environment and be successful,” she says. “There are really so few animals that are able to live out there and thrive.”

One of the major things that Laidre has learned about narwhals is that they are very skilled at living much of their life at dizzying depths beneath a thick layer of dense ice. But the narwhals are not always on top of things….

Signals from the Arctic

A large entrapment of several hundred narwhals was discovered near Pond Inlet, Canada, in 2008. The photo shows a group of narwhals stranded in a shrinking opening in the ice. Credit and Copyright: Brian Koonoo

In recent years, Laidre heard reports of large groups of narwhals dying in “entrapments,” where sudden shifts in the wind or quick drops in temperature rapidly freeze over the leads where narwhals surface to breathe. The whales are left stranded without enough breathing holes to lead them to open water, and hundreds of them will squeeze into shrinking openings in the solid ice. Many narwhals suffocate and die while fighting for air in these tight spaces. Others become easy prey for polar bears and other predators that gather around the breathing holes.

After many years of studying marine mammals in the Arctic, Laidre knows that entrapments are a natural casualty of living in such a harsh and dangerous environment. Although people rarely witness the events because they happen in remote areas, the Inuit have long known about this phenomenon, which they call a sassat. Locals, explorers, hunters, and researchers visiting the region have documented entrapments throughout the past 100 years, but many more have probably gone unnoticed.

The map shows the locations of four recent entrapment events that took place from 2008-2010, and the approximate areas where narwhals gather during the winter and summer seasons in Baffin Bay. The narwhals were found trapped in the vicinity of their summering grounds even though ice entrapments occur most frequently during the winter when the narwhals are located farther south. The narwhals that were trapped in mid-February 2008 are part of a separate population that occurs on the eastern side of Greenland. Credit: NOAA climate.gov

But some of the entrapments that have occurred in recent years stood out to Laidre. They were occurring during a time of the year when entrapments do not usually occur, and in locations where these events had never been observed before. The narwhals were found trapped in the vicinity of their summering grounds up north, even though ice entrapments occur most frequently during the winter when the narwhals are located farther south.

The narwhals were in the wrong place at the wrong time. Laidre began to wonder if these events were a sign that narwhals were being caught off guard by changing sea ice conditions caused by rapid warming in the Arctic.

It is too soon to tell if sea ice entrapments are a sign of a more prolonged change or trend, or if these are random events in the record. But in the meantime, Laidre wants to try and gain a better understanding of how changing sea ice conditions in a warmer future might impact narwhals. She needs to consider everything she has learned about narwhals after more than a decade of studying them. She also must take into account the narwhals’ close and complicated connection with Arctic sea ice—how it influences their movements and behaviors.

“You can’t ignore the fact that the Arctic is changing fast,” Laidre says. “As a marine biologist, I want to understand how these changes will affect the animals and their habitat, and whether they’ll be able to adapt to changes in the future.”

Laidre believes it’s important to monitor Arctic species because they are going to be among the first to experience the signs of climate change. “In a way,” she says, “these species can provide signals to all of us about bigger changes on our planet and in our ecosystems.”