Polar bears have long been a symbol of the dangers of climate change. Majestic, top-of-the-food chain predators like this have this ability to inspire us.
The most dire predictions portend mass starvation and extinction for polar bears, possibly by the end of this century. This is because current models have Arctic sea ice, the traditional polar bear seal-hunting grounds receding to the point the bears will be stuck on land for up to half the year by 2068.
But now, a new study published in the journal PLOS ONE suggests the bears would be able to survive the new ice-free reality by switching from seals to caribou. Researchers Linda Gormezano and Robert Rockwell calculated the amount of energy required to hunt terrestrial food sources and found it was comparable.
Of course, just because something is possible doesn’t mean the bears would necessarily make the switch. Climate change, the narrative goes, is happening too quickly for species make this kind of adaptation.
Chances are polar bears would, however. Polar bears, like most bears, are opportunists. They hunt, they scavenge prey from other predators; they will even steal your pic-a-nic basket.
In fact, Gormezano and Rockwell show that polar bears have supplemented their diet from terrestrial sources for at least as long as humans have been keeping natural history records. They probably always have.
That’s the good news. The bad news is we really do not know what the overall impact of climate change will be because everything is interconnected.
For example, another recent study also published in PLOS ONE, the severe drought, which has been the cause of a particularly destructive wildfire season in the Pacific Northwest, is having a very negative impact on alpine amphibians.
“We’ve seen that the lack of winter snowpack and high summer temperatures have resulted in massive breeding failures and the death of some adult frogs,” said co-author Wendy Palen, an associate professor at Canada’s Simon Fraser University who has for many years studied mountain amphibians in the Pacific Northwest. “More years like 2015 do not bode well for the frogs.”
Of course, frogs, toads, newts and salamanders are bottom-of-the-food chain sustenance for birds, snakes and small mammals, which in turn feed larger predators all the way up to mountain lions, wolves and bears.
No one relationship between predator and prey can be looked at in isolation. With climate change, it’s difficult to know the difference between good news and bad
