Polar bears are traveling farther to find a meal as sea ice in the north shrinks.
The white bears, made popular in animated Coca-Cola commercials, need a lot of food. Males can grow up to 1,500 pounds and stand almost 10 feet tall, while females are about 8 feet tall and can weigh around 550 pounds.
Traveling farther to find food means fewer bears are surviving, according to a recent Washington State University study. In the Beaufort Sea area north of Alaska, populations have dropped by almost one-third.
“Having to travel farther means these bears are expending more energy which can threaten their survival,” said Anthony Pagano, a postdoctoral researcher in WSU’s School of the Environment and lead author of the study. “If we want to preserve the habitat of these amazing mammals, then we need to focus on the root of the problem, which is slowing global climate change.”
For the study, Pagano and colleagues from the U.S. Geological Survey used satellites to investigate the movements of female polar bears from 1986-2016. The bears’ favorite food is seals.
During the early summer when seal pups are small and easier to catch, polar bears can double their body weight from eating the fatty meat.
But as the sea ice melts, the bears have to find new places to hunt, requiring them to walk farther north where there are fewer seals to eat. Some bears are looking for different sources of food, moving into areas along the coast of Alaska and Canada in search of berries and dead animals. Whale carcasses left by resident hunters are a big attraction.
“Sometimes you’ll have 50 to 100 polar bears that congregate around these whale carcasses and compete with each other for food,” Pagano said. “As more and more bears move on land, I suspect there’ll be a lot more competition for these food resources, and we’ll probably start seeing further decreases in abundance and survival.”
To help the 800 or so remaining polar bears in the region, humans need to cut their carbon emissions, which are the main cause behind arctic sea ice melting. Things that produce carbon emissions include automobiles and airplanes, as well as burning coal and gas for energy.
— Brett French, firstname.lastname@example.org