Polar Bears Now Must Swim For Days; Up To 50% Of S. Beaufort Sea Population Gone 2001-2010

[hatrack]

EDIt

"Ice is changing so quickly that we’re finding the bears are getting caught in places where they’re finally coming to the realization, 'I just can’t stay here,' " Derocher said in a phone interview. "... These kinds of long-distance swims are not what they evolved to undergo."

The results of Derocher's study, published in the most recent issue of the journal Ecography, show a dramatic increase in the number of polar bears paddling across vast expanses of ocean to find suitable ice to stand on. In 2004, just a quarter of the bears monitored performed a long-distance swim (defined as more than 50 kilometers, or about 31 miles). By 2012, that proportion had ballooned to 69 percent. The number of bears making such a swim was directly proportional to the loss of sea ice in the area, Derocher said.

These journeys are hard on polar bears. Though they're good swimmers, they're not adapted to long trips and can only paddle about 2 kilometers an hour. A 30-mile journey to find new ice takes an entire day, during which the bears can't eat or rest. Adult bears are likely to lose weight, and their cubs tend to get hypothermic. In 2009, a mother bear who swam for nine days straight off the coast of Alaska (who was not part of Derocher's study) lost 22 percent of her body weight, biologists with the U.S. Geological Survey reported. Her year-old cub died during the journey.

"With cubs, if they have to undergo a long distance swim, it's basically a death sentence," Derocher said. Mothers with cubs were much less likely to swim, he found. Instead, "they will walk for hundreds of kilometers to keep their cubs out of water."

EDIT

https://www.washingtonpost.com/news/speaking-of-science/wp/2016/04/21/melting-arctic-ice-is-forcing-polar-bears-to-swim-for-more-than-a-week-without-rest/

[rjsquirrel]

1. Polar bears come to realizations? Eom