Less sea ice means polar bears are swimming longer

Written by on May 2, 2016 in Marine Life

New research from the University of Alberta reveals that an increasing number of polar bears have been undertaking long-distance swims, which can be dangerous.

Polar bear on Arctic ice.

Polar bear on Arctic ice. Photo credit: Kathy Crane, NOAA.

The researchers defined long-distance as swims exceeding 50 kilometres. Between 2004 and 2012, the number of polar bears that undertook long-distance swims more than doubled in some years. The increase is a result of a loss of sea ice due to climate change.

“Recent studies indicate that swimming may be energetically costly to polar bears,” lead author Nicholas Pilfold explained in a news release. “Given the continued trend of sea ice loss, we recognize that an increased frequency in the need to engage in this behaviour may have serious implications for populations of polar bears living around the Arctic Basin.”

The researchers found that in 2012, when sea ice was at a record low, 69% of adult females in the Beaufort Sea swam more than 50 kilometers at least once. In years where less ice melted completely, less than 30% of the bears swam long distances. Bears in the Hudson Sea, where sea ice melt hasn’t changed, were less likely to undertake long-distance swims.

“While polar bears as a species are eminently suited to swimming, not all bears are equally able to swim long distances,” said study co-author Andrew Derocher. “The youngest, oldest and skinniest bears are much more vulnerable to drowning. With more open water, we can expect increased mortality associated with more long-distance swimming.”

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Copyright © 2016 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of MarineScienceToday.com. She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .


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