Tag Archives: December

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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December is Polar Bear Nativity Month

Polar bears are generally out of sight at this time of year and will be for several more months. Pregnant females will be snug in maternity dens giving birth and all others will be out on the sea ice looking for seals to eat – if they can find them in the dark.

In most areas of the Arctic, December is when polar bear cubs are born, although in southern regions (like Western and Southern Hudson Bay), some may be born in late November and in the far, far north, a few may be born as late as early February.

The actual “date of birth” for polar bear cubs is often back-calculated from when they emerge with their mothers in the spring, because they are born well away from our prying eyes in the dark of the Arctic winter, deep with a snow or soil den dug for that purpose (see previous post here). So our knowledge of the “true” dates of birth in various regions is limited. We have some evidence from native Canadian hunters prior to 1968, when it was both legal and common practice in Canada for Inuit to hunt bears in their dens (Van de Velde et al. 2003), and from a few scientific research expeditions (Amstrup and Gardner 1994; Harington 1968; Ramsay and Stirling 1988; Derocher et al. 1992).

Polar bear cubs, like all bears, are born tiny and rather undeveloped (see Figs 1 and 2 below). Their eyes do not open until about one month after birth. By the time they are 63 days old (two long months after birth, see Toronto Zoo photo here ), their eyes are wide open and they are well furred. Keep in mind, for perspective, that domestic dogs are born after a 63 day gestation period and their eyes open at about 12 days.
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