Polar bears need diet consisting of more than land-based food to survive

Polar bear walking on ice

It’s been a bad week for Canada’s iconic natural wonders. New research suggests that the glaciers in the Rockies could disappear by 2100 and Canada’s boreal region is shrinking from forest fires, all due to the rising effects of climate change.

And because bad news comes in threes, a new geological survey has found that polar bears may not be able to find enough food to survive should their icy homes continue to melt, making it more difficult to catch seals.

Karyn Rode, a wildlife biologist with the U.S. Geological Survey, researched whether a diet of land-based food would be nourishing enough to sustain the huge mammals that mostly feed on blubbery seals.

According to her research, Rode found that the caloric benefit of terrestrial foods like bird eggs, berries, and caribou calves did not have the same value as their current diet.

“There is evidence that some bears are using terrestrial sources in a place such as Hudson Bay, but there’s been no evidence that it’s contributing a significant amount to their energy requirements,” Rode said to the Associated Press.

Another author of the paper, Steven Amstrup, who is the chief scientist at Polar Bear International, summed up the current situation even more succinctly: no ice, no polar bears.

“This paper establishes in no uncertain terms that polar bears are very unlikely to be able to make a living on land, and that if we don’t save the sea ice, polar bears will indeed be gone,” wrote Amstrup in an emailed statement to the Associated Press.

Rode and Amstrup also note that on land, polar bears will also need to compete with Arctic foxes and grizzlies for dinner.

“A really large bear has high energetic costs when they get up to forage, and these [land-based] resources are typically lower in calories or widely dispersed,” said Rode to LiveScience.

 For example, the amount of energy it takes to find berries and bird eggs, compared to the nutrients they’ll reap from their foraging, might not pay off calorically.

If forced to eat a diet of only land-based food, there’s likely going to be some hungry bears out there.