This is scientific American 60 second science. I'm Julia Rosen. Got a minute?

Polar bears live most of their lives on floating rafts of sea ice hunting for seals.

But in the Arctic Ocean north of Alaska, the cold polar wind

constantly blows that ice from east to west, which means that the polar bears there are on a kind of

treadmill. If the bears don't compensate that drift, they would all drift to Russia. So over

the course of a year they need to walk back against that prevailing drift to remain in the

Alaska Territories. David Douglas, a biologist with the U.S. Geological Survey in Juneau, Alaska.

Recently, researchers realized that the ice drift in this part of the Arctic Ocean has accelerated

from about 3 kilometers per day up to 5.

That's probably because climate change has made the sea ice

thinner and easier for the winds to push.

And that means the Polar Bear treadmill has sped up too.

Douglas and his colleagues tracked

Alaskan polar bears fitted with radio collars. They found that the

animals are working harder than ever to compensate for the faster drift. And just

like when we exercise, bears have to eat more food to make up for the extra

calories they're burning. Between one and four more seals per year, depending on whether the bears

are single or raising cubs.

While that may not seem like a lot of seals are a big demand,

it also comes at a time when the habitat

that they have to hunt in is shrinking.

So they have less area on which to hunt seals

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