One of the reasons why the bowhead whales make their way to Cumberland Sound, Nunavut, during the summer is now cleared up, and it's thanks in part to drones.

From the look of things, these marine mammals have chosen the Canadian Arctic as their go-to place to remove their molted dead skin or, in other words, exfoliate using the rocks in the area.

Historical Mystery Partially Solved

Bowhead whales rubbing their backs against boulders has quite a history that dates back to the 19th century by the Inuit and whalers at the time, but while the phenomenon has been observed and recorded, the purpose hasn't been clear.

Now Sarah Fortune, a PhD student at the University of Columbia's Institute for the Oceans and Fisheries, and her colleague William Koski, a whale biologist of LGL Limited, have authored a new study that goes deeper into the mysterious behavior in question, providing an explanation of why the large mammals rolling onto their sides and raising their flippers and tails around the craggy rocks near the shore of Baffin Island.

While on a boat with Inuit hunters of the area and Pangnirtung fishers, Fortune, Koski, and their companions saw the bowhead whales going through their curious performance. To get a closer look at things, they operated drones to get an aerial view of the animals and record what was happening, and that's when they determined that the mammals were rubbing against rocks to exfoliate.

Happy Accident

Fortune wasn't out there to acquire footage and solve the mystery behind the bowhead whales' purpose of coming back to Cumberland Sound, Nunavut, though. She was there to observe their feeding behavior and how it's been affected by climate change.

"This was an incidental observation. We were there to document their prey and feeding behaviour, but we noticed some strange behaviour near the shore," Fortune said.

Of course, now it has been confirmed that bowhead whales do indeed molt and use rocks to help them cleanly remove their dead skin. In other words, the area is apparently not just for feeding.

"We now know that Cumberland Sound serves as a habitat for feeding and molting. Very little is known about molting in any of the large whale species," Fortune continued.

As for why the marine mammals chose Cumberland Sound for their shedding, it's believed that the relatively warm water there makes it easier for the whales to remove their dead skin.

This study is published in the journal PLOS One.