Nunatsiaq Online
NEWS: Nunavut April 12, 2017 - 2:30 pm

How do polar bears find prey? The answer is blowing in the wind

Bears use crosswinds to track their prey

SARAH ROGERS
New research has found that travelling crosswind maximizes the area polar bears can sense through smell while they're hunting. (PHOTO COURTESY OF A. DESROCHER)
New research has found that travelling crosswind maximizes the area polar bears can sense through smell while they're hunting. (PHOTO COURTESY OF A. DESROCHER)

Polar bears along the western Hudson Bay coast have varied success in their quest to find ringed seals to eat.

But new research has found that the answer to that success is blowing in the wind. More specifically, a polar bear’s success as a predator depends on how they move relative to the wind.

Research has already established that polar bears, like many mammals, use their sense of smell to find food, an important tool given those animals cover large habitat where sea ice can obstruct their view during most of the year.

“We know how important their sense of smell is for finding seals,” said Ron Togunov, a Masters student at the University of Alberta and lead author of the new study Windscapes and olfactory foraging in a large carnivore.

“How they move through their environment to maximize that area they’re perceiving through the smell—that’s been largely theoretical. So we examined polar bears to see how they move, relative to wind.”

While travelling, polar bears can move in three directions; upwind, downwind or crosswind, a direction that would be perpendicular to the way the wind blows.

University of Alberta researchers have been collaring female polar bears along western Hudson Bay since 2004 as part of a long-term monitoring project.

Using that data and wind data collected by the U.S. National Oceanic and Atmospheric Administration (NOAA), researchers found that, in certain conditions, the polar bears use crosswind movement to track their prey.

“Travelling crosswind gives the bears a steady supply of new air streams and maximizes the area they can sense through smell,” Togunov explained.

Data shows the animals moved crosswind most often in the winter months, when winds were slow, and at nightt ime when their vision was less effective.

That proved key while bears were navigating the sea ice which can be flat but can also be heavily layered with pressure ridges, allowing seals to hide out of sight.

During the summer months, when polar bears are on the land, researchers found their olfactory use was random and limited—which makes sense, given the bears aren’t hunting seals that time of the year.

Although biologists have long speculated that wind direction and hunting success were related, Togunov said it’s exciting to finally back up that theory with evidence.

“This hasn’t been quantified in any mammals, although it’s been suspected for decades,” he said.

The research points to other potential implications for polar bears as the climate changes, given that higher wind speeds correlate with a less successful hunt.

Wind speeds in the Arctic are projected to increase overall, Togunov said, which could create more challenges for polar bears and impact how successful they are harvesting.

“We are seeing more polar bears entering human communities [and] these are usually bears with lower body conditions, usually starving,” he said.

“If the increase in winds speeds decreases their hunting success, then that could be another element—on top of decreasing ice cover—that further stresses the bears.”

Windscapes and olfactory foraging in a large carnivore was published this month in the journal Scientific Reports.

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(11) Comments:

#1. Posted by Gjoa Boy on April 12, 2017

Why does everybody else study our polar bears? Why does Nunavut never publish studies about our own bears? Our government is a joke.

#2. Posted by Just wandering on April 13, 2017

#1 Do you mean why isn’t the GN doing these studies, or why aren’t Inuit doing them?

#3. Posted by Prosperous Polar Bears on April 13, 2017

We know them intimately - we know there are more bears than ever before and we know how very adaptable they are.  There are bears that live year round on sea water - they eat, sleep, hunt and reproduce on sea and outsiders think they’re threatened and endangered due to climate change?

Talk to Inuit elders with an open mind and open heart - you will definitely learn something new, poster Just wandering!

#4. Posted by Bio Hazard on April 13, 2017

Hey #1 you don’t get out much. GN does studies and surveys on polar bears all the time, just about every year LOLZ

http://www.nunatsiaqonline.ca/stories/article/65674gn_polar_bear_survey_highlights_benefits_of_non-invasive_research_meth/

#5. Posted by Just wandering on April 13, 2017

#3 Your response to my very simple question is very interesting, and very telling for that matter.

Look at all the things that I never mentioned, that you did. So weird. By the looks of it this study has nothing to do with the bear population. 

But then I bet that no matter what someone says you see the same themes over and over, am I right?

Maybe you need to open your own heart and mind.

#6. Posted by Gjoa Boy on April 13, 2017

#2, we already know that our own people know and understand the polar bear. But we dont have the voices to speak or do studies. So I am wondering why our own biologists never publish studies on polar bear research. They count them every year. Why are people who dont even live in Nunavut the only people who ever seem to have a voice about the bears here?

#7. Posted by Just wandering on April 14, 2017

#6

My guess would be that maybe there aren’t that many Inuit writing peer reviewed studies on the polar bear in academic journals?

There’s probably no reason they couldn’t though.

What do you think the reason is?

#8. Posted by Ross on April 14, 2017

Mr Togunov I knew this since I was 10 years old, when I started hunting….Hint, your next great discovery will be that the mother polar bears leave their den which coincide with seals having their pups, for your info. Also during spring that’s when they fatten up for the summer holidays, also for your info….Every new discovery you make about our nanook is nothing new to me, or any other arctic species for that matter….You really want to know more about our arctic species…Talk with any hunter such as myself next time. Before you make a FOOL and an IDIOT of yourself again, on your so called new discoveries.

#9. Posted by Easter bunny on April 14, 2017

#8 I dare say the only one making an idiot of themself here is you with that ugly attitude.

By the way, the greatest fools are those who have fooled themselves they have nothing to learn from anyone.

#10. Posted by Bill Nye on April 15, 2017

Thanks so much for the offer Ross, I don’t know why we never thought ask a ‘hunter’ before to be honest with you.

Anyway, since we’re here, can you tell us about changes in polar bear and brown bear mitochondrial DNA. The thing is, most brown bear mitochondrial haplotypes show strikingly strong geographic structure, likely resulting from female philopatry. The quirky thing being that polar bear mitochondrial haplotypes fall within the range of diversity of brown bear mitochondrial haplotypes, rather than outside of brown bear mitochondrial diversity, as would be expected of separate species.

Weird hey?

Also, we’re interested in gene flow changes between polar and brown bear populations. We’re trying to narrow down the estimated dates of population divergence. So far we believe this to be between 340 thousand to 4–5 million years ago, but this range is fairly wide (granted, there is much debate over this).

And hey, thanks again. Sorry we were such ‘idiots’ before.

#11. Posted by detlef on April 18, 2017

#1 - the publication process in a scientific journal is not simple - it takes time to collect data, years usually, and then also 1-2 years to publish a final artuicle depending on the subject matter; I know from my community that the gn puts out annual report from there field work all the time, maybe your HTo does not read them?

when thhe GN collects the polar bear data for a population it takes a few years to have it finalized like the Baffin bay polar bear study; and besides what the Mr Turgonov studied is not what the GN is supposed to study - there are different ways to look into studying like what is a mandate from the gN like population numbers, or just some academic questions that are nice to know but have little management impact.

if your community knows all the stuff about bears living in the sea all year around why don’t you get the elders together and write it up and give the gn a report?

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