In the cold waters of Cumberland Sound, Nunavut, a Dalhousie graduate student named Manon den Haan attached cameras to the bodies of bowhead whales, revealing something scientists had assumed for years but never truly seen: how these Arctic giants actually feed. For decades, researchers believed that dive shape told the whole story—a long, square or U-shaped plunge meant feeding time. But new evidence shows the picture is far more nuanced than that simple rule.
Using high-resolution biologging tags equipped with video cameras, den Haan and her team, led by senior author Dr. Sarah Fortune, tracked bowhead whales in their natural habitat and discovered that dive shape alone could seriously overestimate how much time these massive animals spend hunting. Instead, the clearest signs of feeding emerged from something far subtler: changes in speed, body angle, and the precise way a whale moves through the water. The findings, published in PLOS One in a study titled "Bowhead whale foraging dives are defined by speed and body orientation," offer the first visual documentation of what feeding really looks like for one of Earth's largest animals.
The research matters urgently because bowhead whales survive on dense patches of tiny zooplankton scattered across an Arctic ecosystem that climate change is rapidly reshaping. If scientists can't accurately identify when and how whales are feeding, they can't understand whether these animals can find enough food as warming waters shift where their prey gathers. "A whale can make the kind of dive we've traditionally associated with foraging and not be feeding at all," Dr. Fortune explains. The old assumption could mask a serious ecological problem.
The video revealed an elegant underwater choreography. Feeding whales slow down, tilt slightly downward, and roll subtly to the side as they filter prey-rich water through their baleen. This wasn't just theory anymore—it was documented in detail for the first time. But the team also uncovered something completely unexpected: bowhead whales swim faster in shallow waters than in deeper ones, a previously unknown variation they adapted to combat tides. Perhaps most strikingly, many whales were feeding surprisingly close to the surface in shallow, tide-driven prey layers, not exclusively in the deep dives scientists had long thought defined bowhead foraging.
These findings ripple outward to conservation and survival. "If we have a better foundational knowledge on how bowhead whales move, we can accurately calculate their feeding efforts as well as their energy expenditure," den Haan notes. "This will help in understanding their survivability in the ever-changing Arctic." It's a reminder that even among the largest animals on Earth, survival depends on details—the precise angle of a roll, the exact moment to slow down, the subtle cues that separate a purposeful hunt from an empty dive.
As Arctic waters continue to warm and transform, this kind of ground-truth knowledge becomes indispensable. Scientists can now watch what whales actually do, not guess based on old assumptions. That distinction might matter more for bowhead survival in the decades ahead than anyone realized.