Jessa Gamble explains how bears are coping with a changing climate:
As caribou migration routes have moved North, grizzlies have followed and started mating with polar bears. Not only have they produced hybrid young, but those young are fertile. Polar bears and grizzlies only diverged about 150,000 years ago and haven’t developed many genetic differences, despite quite dramatic visual dissimilarities. Second-generation hybrids have now been confirmed in the wild. There have been a dozen sightings in only a handful of years, mostly by hunters, and most of those bears were identified after they were shot. It’s also a legal problem, in that you can’t shoot a grizzly with a polar bear license. Grolar bears, or pizzlies – I know, shudder – bring out the excitement of cryptozoology (Big Foot and the Loch Ness monster), but they’re very real.
The bigger picture:
I find myself scouring the photos, trying to tease out both species’ features in them, like a father staring intently at the faces of his children, looking for familial likenesses and possibly proof of paternity. What I end up seeing, in this quintessentially 21st century creature, is a glimpse of the future. Closely related marine mammals from the North Atlantic and the North Pacific are about to merge territories, and we’re likely to see more hybridizing in the years to come.