Bowhead whales like their afternoon siestas.
That’s what UBC’s Sarah Fortune realized after she and her fellow researchers gathered and analyzed stunning drone footage of the mammals in the eastern Canadian Arctic.
“The team was able to watch the whales and found that they spent the early morning feeding in deep water and then rested in shallow, coastal waters during the afternoon,” Fortune said.
She and the team spent four summers in Cumberland Sound, Nunavut — just a few kilometres shy of the Arctic Circle — studying the whales.
She believes this is the first intensive effort to study bowhead whales with the use of an aerial drone, and says researchers now have a better understanding of how the whales forage and travel.
“When you’re on a boat, you can’t observe the entire body … it’s like the tip of the iceberg,” she said.
But the aerial footage, along with the clarity of the northern waters, means researchers can now observe the whales’ body language in real time. Fortune says the whales did not seem bothered by the drones.
“They paid it as much attention as a bird flying over. It was actually quite remarkable.”
Fortune says she is studying the whales to better understand how the whales are affected by climate change.
The bowhead whale is the longest-living marine mammal in the world, yet many questions remain about the biology and feeding behaviour of this elusive animal.
The researchers realized that the whales were not foraging at the surface level, and preferred to dive deeper to eat, even though their prey — small crustaceans — was also at the sea surface.
“Maybe they’re getting better prey deeper. We don’t know why they are doing that yet and want to do some more analysis on that,” Fortune said.
Swimming in formation
It was the social behaviour that fascinated Fortune the most.
“Although it is common to find small groups of whales traveling together, we saw they would often swim in coordinated patterns, almost like a V-formation,” she said.
She theorized the whales swam in that pattern to save energy and ride the updraft.
The whales also often rubbed up against each other in a gentle manner.
“It’s hard to say what this behaviour is about. I think we look at it and as humans want to say it is affectionate, but some of the whales also have roughened skin patches, so maybe this is their way to shed that.”
Fortune says the thousands of images of the whales they collected will be used by other researchers to determine the population size of these whales.
They will use the unique markings to identify the whales, age and body condition.
“This information will be really helpful as we monitor changes to the population’s health over time.”