Tag Archives: polar bears in winter

Tracking polar bears in the Beaufort Sea – February 2015 map

Here is the February 2015 follow-up to my post on the July 2013 track map for female polar bears being followed by satellite in the Beaufort Sea by the US Geological Survey (USGS) – “Ten out of ten polar bears being tracked this summer in the Beaufort Sea are on the ice.”

polar_bear with collar_USGS

See that post for methods and other background on this topic, and some track maps from 2012 (also available at the USGS website here). The USGS track map for February 2015 is copied below.

There were 7 bears in February, up from 6 in January, because one of the bears has re-entered the area from elsewhere. However, many bears from the original sample have either had their collars fail, moved out of the area and stayed out, or they have died. We can’t tell from which of those options, or combinations of them, explain the reduced number still being followed.
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Tracking polar bears in the Beaufort Sea – January 2015 map

Here is the January 2015 follow-up to my post on the July 2013 track map for female polar bears being followed by satellite in the Beaufort Sea by the US Geological Survey (USGS) – “Ten out of ten polar bears being tracked this summer in the Beaufort Sea are on the ice.”

Tranquilized_pb570_S Beaufort March 2014_USGS

See that post for methods and other background on this topic, and some track maps from 2012 (also available at the USGS website here). The USGS track map for January is copied below.

There are only 6 bears being followed now, which means a few more collars have failed, or the bears have moved out of the area or died.
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Tracking polar bears in the Beaufort Sea – December 2014 map

Here is the December 2014 follow-up to my post on the July 2013 track map for female polar bears being followed by satellite in the Beaufort Sea by the US Geological Survey (USGS) – “Ten out of ten polar bears being tracked this summer in the Beaufort Sea are on the ice.”

Tranquilized_pb570_S Beaufort March 2014_USGS

See that post for methods and other background on this topic, and some track maps from 2012 (also available at the USGS website here). The USGS track map for December is copied below.

There are only 10 bears being followed now, which means a few more collars have failed, or the bears have moved out of the area or died.
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Polar bear habitat – more Arctic sea ice in Canada this week than in early 1970s

This week, Arctic sea ice in Canada, where 2/3 of the world’s polar bears live, had more sea ice than was present in the early 1970s. Globally, the ice is spitting-distance close to the 1981-2010 average calculated by the NSIDC for this date – which means lots of winter/spring hunting habitat for polar bears.

Canada sea ice freeze-up_same week_Dec 25 1971_2014 standard average

This is the peak of the polar bear birthing season (both in the wild and in zoos.) Newborns will be snug in maternity dens built by their mothers onshore or on the sea ice; the rest of the population will be out on the ice.

Sea ice extent 2014 Dec 25 NSIDC

Regional ice charts going back to the late 1960s and early 1970s for this week show even more surprises — have a look.

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Polar bears in winter – a seasonal review of insights and research

Here are summaries of my “Polar bears in winter” series. It’s an interesting recap of what polar bears do over the unimaginably cold and dark months of an Arctic winter.

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Hudson Bay sea ice well above average – excellent early December polar bear habitat

Sea ice development for this date is well above average on Hudson Bay – even more so than last week – making three years in a row of average-to-above average ice habitat available to polar bears in early December (see last week’s ice summary here). Coverage for the week of 11 December from 1971 to 2104 below (from Canadian Ice Service):

Hudson Bay freeze-up same week_Dec 11 1971_2014 w average

More maps below (from CIS and NSIDC), see others here.

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Polar bear habitat update – January 2014

Sea ice in the Arctic a bit below the 1981-2010 average for this date  but still within two standard deviations, with more ice than average off Canada — indicating we are still within expected natural variation, statistically speaking.

Remember that the National Snow and Ice Data Center (NSIDC) says this about standard deviation:

“Measurements that fall far outside of the two standard deviation range or consistently fall outside that range suggest that something unusual is occurring that can’t be explained by normal processes.”

Ice maps below, click to enlarge.

 Figure 1. Sea ice and lake ice concentration from the Canadian Ice Service (CIS) for 31 January, 2014. Note the amount of ice in the east, off Labrador (the “Davis Strait” polar bear subpopulation).


Figure 1. Sea ice and lake ice concentration from the Canadian Ice Service (CIS) for 31 January, 2014. Note the amount of ice in the east, off Labrador (the “Davis Strait” polar bear subpopulation).

Figure 2. Sea ice extent from the National Snow and Ice Data Center (NSIDC) for 29 January 2014. Note that the extent of ice in eastern Canada noted in Fig. 1 is slightly more than the 1981-2010 average (the orange line), while other areas have slightly less than average for this date. Compare ice growth over the last month to Fig. 3 below.

Figure 2. Sea ice extent from the National Snow and Ice Data Center (NSIDC) for 29 January 2014. Note that the extent of ice in eastern Canada noted in Fig. 1 is slightly more than the 1981-2010 average (the orange line), while other areas have slightly less than average for this date. Compare ice growth over the last month to Fig. 3 below.

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Polar bear gives birth in Munich zoo, with photos and video

Fabulous photos of 3 week old twin polar bear cubs (born December 9, 2013), have been released by the Hellabrunn Zoo in Munich, Germany. There’s video of the births as well. The newborn cubs are so tiny  — it’s hard to imagine them being born in the dead of winter in a snow den!

PB newborn with mother Munich Zoo Dec 2013

All but one of the photos shown here, including the one above, are of the newborns at 3 weeks of age. The one below is a screen cap taken from the video of the birth, and is the only one that shows the cubs just hours old. They seem to have grown a bit in 3 weeks.

PB newborns birth_11PolarBearTwins2_Zoo screen cap

From this January 1, 2014 account (Hellabrunn Zoo Welcomes Polar Bear Twins”):

“On December 9, a Polar Bear named Giovanna gave birth to two cubs at Munich’s Hellabrunn Zoo. Both births were seen on cameras installed in the birthing den and the connecting corridor to the main den. This is remarkable on two counts: for both births, Giovanna positioned herself so that she was directly in the cameras’ field of view. Secondly, this is the first time that a Polar Bear birth has been filmed in color worldwide!

The cubs were born at 08:39 and 09:43 respectively, to parents Giovanna (7) and Yogi (14). The zoo’s director, Dr. Andreas Knieriem, enthused, “It is as if we were there live watching the labour and birth of a Polar Bear and, as if that weren’t enough, Giovanna showed us not one, but two very different births!”

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Polar bears in winter: starving bears and attacks on humans

Winter in the Arctic can be a tough time for polar bears. Between the cold, darkness and ever-thickening sea ice with fewer open leads, polar bears often find that seals are hard to come by.

So it should not be surprising to find out that polar bears are at their lowest body weight at the end of winter (Ramsay and Stirling 1988:613; Stirling 2002:68).

In other words, polar bears lose weight over the winter – not just during the ice-free summer period. That’s why the spring and early summer feeding period is so critical: gorging on young seals rebuilds the polar bears’ fat reserves lost over the winter and packs on even more fat to tide them over the late summer/early fall ice-free period.

Last fall, a potentially serious attack by a polar bear on a Churchill, Manitoba resident on Hallowe’en night (early hours of November 1) got a lot of attention worldwide. Some media outlets suggested that the bear involved in this attack was either starving or so hungry that he was driven to attack. However, this assertion was not supported by any evidence — we simply don’t know whether he was in poor condition or not. While the bear was undoubtedly leaner at the end of October than he was in July, that doesn’t mean he was actually ‘starving.’

So, here’s the question: given that polar bears have a tough time finding seals to eat during the dark and cold Arctic winter and are presumably at their hungriest then, do serious polar bear attacks on humans also happen in winter?
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Polar bear winter: a spectacular Northern Lights video from Finland

polar bear aurora_borealis_3-t2 freeWith the winter darkness in the Arctic comes the splendor of the Northern Lights — Aurora Borealis.

Yesterday, a short video clip of photographer Thomas Kast’s time-lapse Northern Lights video “Aurora – Queen of the Night” was posted at Alaska Dispatch, Time-lapse images show northern lights over Finland. There are no polar bears in the film but it is evocative of Arctic landscapes this time of year — when only the Northern Lights and the moon brighten the sky: Continue reading