Which set? The ones who sexed the cub in infancy, or the casual observers who got it right watching the bears urinate?
I suspect that the population of polar bears is shifting their hunting territory and this is only noticed by the folks who live there full-time, permanently, and have the opportunity to observe the polar bears on a regular basis. Environmental researchers have notoriously poor budgets to work with and don't conduct continuous surveys. Keep in mind that the hunting industry in Alaska and North Canada is a very lucrative business, and for some communities it is one of the few employers. So take this article with a grain of salt and skepticism. Everyone has an agenda, and I mean both sides. Continuation of reasonable hunting quotas is important in preserving our environment. Especially true when pelts are getting $15K a pop or more. Remember that it is widely believed within the scientific community that Clovis Man caused directly or indirectly the extinction of many large mammals on this (North/Central/South America) and other continents. There were no hunting quotas back then.