A US Geological Survey study reports in the Canadian Journal of Zoology that female polar bears can swim dozens to hundreds of miles, sometimes taking more than a week in the water between rest breaks on ice or land. At Reuters Yereth Rosen gets right to a burning question: how about male polar bears? He explains the bias this way: their necks are too thick for the GPS-equipped collars. Some of the svelter lady bears that were studied did so with cubs.
Reuters also reported that despite the temptation perhaps to take this as a sign bears will be resilient if large expanses of of the Arctic Ocean lost their summer ice, the lead author warns that the study sample is too small to draw conclusions about polar bear fate as climate changes.
Also quick off the mark - and perhaps the source of the Reuters note on neck girth - was NYTimes's Andrew C. Revkin at his Dot Earth blog spot. He points out that long swims are not that uncommon for Ursus maritimus. Fifty swims had an average length of 96 miles. Revkin, interviewing the lead author, Revkin asked him what to make of reports a few years ago of drowned polar bears. The researcher said he suspects a powerful storm was a factor, adding that in general polar bears are clearly capable of amazingly long swims. In the Beaufort Sea study region off northeastern Alaska , the USGS expert said the local polar bear population recently has appeared stable at around 1,500.
A more pointed angle is found at LiveScience by Wynne Parry. She (corrects earlier ref. to 'he,' sorry for the careless error) reports not only that the bears routinely swim far, but (or least the headline does) that loss of sea ice is forcing them to do so. Her story explains that nobody knows if such marathon swims are new for the bears. It backs up the hed by noting that until recently, in the Beaufort Sea there was too little extended open water for such long swims. That is not quite the same as saying open water is now forcing them to keep swimming. Maybe. Maybe not.
Even more directly tying polar bear swimming capacity to climate change is Time Magazine's Bryan Walsh, who runs the news under the hed "Can Polar Bears Keep Their Heads Above Water in a Warming World?"He writes, in confessed speculation, that the study "provides clues that polar bears may be able to keep treading water even as climate change melts their habitat." It is a speculation that the USGS's press release offers but does not back up with anything attributed to the study's authors.
Other Stories:
- Alaska Dispatch - Alex DeMarban: Study finds that polar bear moms, some cubs swim long distances ;
- Alaska Public Radio Network - Annie Feidt: Study Reveals Polar Bears' Long Distance Swims ;
Grist for the Mill: USGS Press Release ; Paper abstract ;
- Charlie Petit
