Thanks for the info about recent knowledge about how well bear spray works.

Does anyone know about experiences with using bear spray on polar bears? My ambition is to make a new trip into polar bear country (Spitsbergen) within the next few years or so. Last time I was there, the general advice was to bring a heavy caliber rifle.

I wouldn't be surprised if someone demonstrates that pepper spray works on polar bears, too. Until then the old advice about guns still apply...

Don't know much about Alaskan or North American bears, but polar bears are notoriously unpredictable. Most of the time they will prefer to leave humans alone, but they can also be very inquisitive and turn aggressive at the spur of the moment.