Al Gore and others have shamelessly exploited public ignorance about the polar bear in order to spread fear. Ed Caryl tells us why the polar bear will do just fine.
The Polar Bear
by Ed Caryl
The climate change “team” regularly invoke the polar bear as the “poster-boy” for the supposed danger in catastrophic anthropogenic global warming.
Figure 1: Female polar bear (ursus maritimus) near Kaktovik, Barter Island, Alaska. (Source: Wikimedia Commons).
The polar bear, ursus maritimus, is descended from the Brown Bear, ursus arctos. The genetic split took place sometime between 300,000 and 600,000 years ago, but the split was never fully complete. Polar bear mitochondral DNA (mDNA) is descended from a female brown bear, perhaps from Ireland, which dates back to the middle of the last ice age, 50,000 to 100,000 years ago. During that encounter, a male polar bear mated with a female brown bear. The subsequent offspring then mated with polar bears, and the mDNA from that female spread across the population. That suggests that population pressure on polar bears doesn’t necessarily happen only when it warms up, but also when it gets very cold. Both conditions reduce the first-year sea ice that makes prime habitat for the seals that polar bears favor; cold covers it with glaciers and warm melts it.
There isn’t much genetic difference between polar bears and other brown bears. They can freely mate, and the offspring are fertile, indicating that they are the same species. The Latin name should be ursus arctos maritimus, similar to the grizzly bear ursus arctos horribilus. These “hybrids” happen often in the Canadian Arctic, and even have locally bestowed names, Grolar or Pizzly Bears. The environmentalists have decried these occurrences, claiming that it will lead to the demise of their favorite animal. In my opinion, this provides genetic diversity that has assisted survival in the past, and will in the future.