Early-birthing polar bear female with new cubs out on the ice already in Western Hudson Bay

From Polar Bear Science

At least a month earlier than in more northerly areas of the Arctic, the first known female with new cubs-of-the-year has been reported on the sea ice hunting for seals in Western Hudson Bay. Remember this when the cries of “early” breakup of sea ice on Hudson Bay come in the summer: these WH bears routinely get a head start on spring feeding that other bears don’t get.

Bear O4 just left her den & made it to the sea ice (bear closest to coast): likely with her cubs out to hunt. She needs to rebuild depleted fat depots for next summer.

Here is the map he included, on which I’ve circled “Bear 04”:

As I’ve stated previously, 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 at about 3 months of age, because they are born well away from our prying eyes in the dark of the Arctic winter, deep within a snow or soil den dug for that purpose. 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).

It appears that the female shown on Derocher’s map (“04”) indeed must have given birth in late November in order to have cubs old enough to be well offshore by 4 March. In other words, the family were likely out of their den, getting ready to move out, close to the middle of February (presuming this female indeed has cubs with her, which has not been confirmed).

This female’s location in early February:

For comparison, the video below offers a discussion of polar bear den studies in Svalbard, produced by Polar Bears International in 2021. They map they show indicates how much further north Svalbard is than Western Hudson Bay.

Keep in mind that since sea ice conditions have changed around Svalbard (about 2003), most pregnant females make their dens on the sea ice or in Franz Josef Land. And despite pessimistic prognostications for the future, Svalbard bears (including adult females) have been doing very well despite much less sea ice (Lippold et al. 2019:988), as Jon Aars honestly admits in the video.

References

Amstrup, S.C. and Gardner, C. 1994. Polar bear maternity denning in the Beaufort Sea. Journal of Wildlife Management 58:1-10. http://www.jstor.org/discover/10.2307/3809542

Harington, R. C. 1968. Denning habits of the polar bear (Ursus maritimus Phipps). Canadian Wildlife Service Report Series No. 5., Ottawa

Lippold, A., Bourgeon, S., Aars, J., Andersen, M., Polder, A., Lyche, J.L., Bytingsvik, J., Jenssen, B.M., Derocher, A.E., Welker, J.M. and Routti, H. 2019. Temporal trends of persistent organic pollutants in Barents Sea polar bears (Ursus maritimus) in relation to changes in feeding habits and body condition. Environmental Science and Technology 53(2):984-995.

Ramsay, M. A. and Stirling, I. 1988. Reproductive biology and ecology of female polar bears (Ursus maritimus). Journal of Zoology London 214:601-634. http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.1988.tb03762.x/abstract

Van de Velde (OMI), F., Stirling, I. and Richardson, E. 2003. Polar bear (Ursus maritimus) denning in the area of the Simpson Peninsula, Nunavut. Arctic 56:191-197. http://arctic.synergiesprairies.ca/arctic/index.php/arctic/article/view/615

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strativarius
March 7, 2023 2:48 am

In anticipation of good news in the Arctic the focus of attention has shifted to the newly endangered Antarctic….

“…across those four decades of satellite observations, there has never been less ice around the continent than there was last week. “By the end of January we could tell it was only a matter of time. It wasn’t even a close run thing,” says Dr Will Hobbs, an Antarctic sea ice expert at the University of Tasmania with the Australian Antarctic Program Partnership. “We are seeing less ice everywhere. It’s a circumpolar event.”

In the southern hemisphere summer of 2022, the amount of sea ice dropped to 1.92m sq km on 25 February – an all-time low based on satellite observations that started in 1979.”
https://www.theguardian.com/world/2023/mar/04/everyone-should-be-concerned-antarctic-sea-ice-reaches-lowest-levels-ever-recorded

And so, good news has yet again been avoided and the narrative maintained.

Reply to  strativarius
March 7, 2023 3:16 am

Jan and Feb 2023 both set new monthly average record low sea ice extents in Antarctica (record starts 1979). Luckily they don’t have any polar bears.

strativarius
Reply to  TheFinalNail
March 7, 2023 3:23 am

Funnily enough it has colonies of Penguins yet to be discovered.

“Scientists discover emperor penguin colony in Antarctica using satellite images”
https://www.theguardian.com/environment/2023/jan/20/scientists-discover-emperor-penguin-colony-in-antarctica-using-satellite-images

Luckily they don’t have any polar bears

Who are ‘they‘? Is that wokese for ‘it’; the Antarctic?

Reply to  strativarius
March 7, 2023 3:51 am

Who are ‘they‘?

The penguins!

strativarius
Reply to  TheFinalNail
March 7, 2023 4:08 am

Why would they have Polar bears?

Have you lost your senses?

NB That’s a rhetorical question

Scissor
Reply to  strativarius
March 7, 2023 5:27 am

Luckily the residents of McMurdo Station have balmy summer weather to enjoy.

https://www.timeanddate.com/weather/antarctica/mcmurdo

strativarius
Reply to  Scissor
March 7, 2023 6:02 am

It seems The Final Nail is in fact a down vote.

jorge
Reply to  strativarius
March 7, 2023 6:33 am

Studies have shown that Emperor penguins keep polar bears as pets.
(Studies have shown that the words “Studies have shown” are followed by a fib 86.7% of the time.)

Reply to  TheFinalNail
March 7, 2023 2:42 pm

Wow, 15 down-votes (and counting) for mentioning the simple fact that Jan and Feb 2023 set new record low monthly average sea ice extent records in Antartica.

Glad I didn’t also mention that June, July and August 2022 also set new record low average monthly Antartic sea extents; or that 2022 set a new annual average low.

That would be too much. Too much.

Reply to  TheFinalNail
March 8, 2023 12:16 pm

Any news on why the dramatic difference compared to recent years where ice extent was above average?

Has it been particularly stormy these past few months?

ResourceGuy
March 7, 2023 5:41 am

Is this good or bad news for T-shirt sales of the WWF and other agenda merchants?

n.n
Reply to  ResourceGuy
March 7, 2023 8:54 am

Good news. Our “cute” Posterity has a big, forward-looking market.

Ireneusz Palmowski
March 7, 2023 9:46 am

Should we be worried about the Arctic?
comment image
Current temperature above the 80th parallel.
comment image

Reply to  Ireneusz Palmowski
March 8, 2023 12:21 pm

Would be great if it all melted and averaged out to spring type conditions – certainly that’s what the flora and fauna there would want.

Eben
March 7, 2023 12:03 pm

People who are 10 years behind in the climate debate are still counting polar bears and penguins

March 7, 2023 12:36 pm

There are now more Polar bears than at anytime over the last sixty years but ask anyone in the street what’s happening and they’ll tell you that they’re all going extinct.