Polar Bear Hair Sheds Light on Seal Populations Under the Arctic Sea Ice

September 24, 2022

Polar bear diets should be filled with a lot of fat. So much fat that some researchers study them just to understand how a species that consumes a diet with up to 80% blubber avoids heart disease and obesity.

However, a new study shows that as the Arctic warms faster than any other part of the world, polar bears can’t feast on blubber from multiple seals as they’re used to doing. Instead, they’re finding fewer seals and eating more muscle, increasing their consumption of protein relative to fat. Blubber is highly digestible and provides twice the energy per gram compared to muscle.

“Polar bears have evolved to specialize on a high fat diet composed primarily of seal blubber,” Karyn Rode, the lead author and a USGS research wildlife biologist, said. Her team’s new study shows that when polar bears ate less fat from fewer ringed seals, they were less likely to survive the year.

“Understanding how polar bears respond to periods of reduced access to their primary prey, and consequently reduced dietary fat, helps us better understand the implications of Arctic warming on these predators while simultaneously shedding light on the status of their prey populations,” Rode said.

Satellite images show that the Arctic is losing sea ice, which polar bears use for roaming and hunting. This new study reveals how the melting sea ice is also affecting the seals, whales, and other creatures that are part of the ecosystem beneath the ice.

Keep reading: https://esajournals.onlinelibrary.wiley.com/doi/10.1002/eap.2751

Read the Ecological Applications paper: https://esajournals.onlinelibrary.wiley.com/doi/10.1002/eap.2751