Lifetime of polar bears captured on collar cameras

Muriel Hammond
February 2, 2018

Because of melting sea ice, it is likely that more polar bears will soon starve, warns a new study that discovered the large carnivores need to eat 60 percent more than anyone had realized.

The vision of a polar bear plucking a vulnerable seal off an ice floe is something familiar to wildlife documentary fanatics, BBC reports.

They collared nine adult female polar bears on the sea ice of the Beaufort Sea in Alaska with a Global Positioning System video camera and observed the bears for discreet time periods over three consecutive years.

The scientists also analysed blood and urine samples taken at the beginning and end of each bear's 8-11 day journey across the ice fields to ascertain the animal's metabolic rate.

The study published in Thursday's journal Science had been counducted on those white giants during the month of April and finds that shrinking of ice is causing the weight lose of those bears which is not good for them. Their energy consumption as calculated during the study was 1.6 times higher than previously thought.

Of the 9 bears in the study, more than half lost body mass during observation, which was conducted during what is supposed to be the most active hunting period of the year.

In December previous year, a video of a dying polar bear rummaging in trash and eating styrofoam, assumed to be starving, went viral on social media.

A polar bear tests the strength of thin sea ice.

The Arctic is warming twice as rapidly as the global average, diminishing the sea ice that polar bears rely upon for food and forcing many to embark from water on to land where they desperately forage for goose eggs or rubbish from bins in far-flung towns.

Polar bears find it hard to catch enough food, even in the best hunting season

Four of the bears, mostly the older ones, did gain as much as 10 percent of their body mass over the study period.

The reason behind this is, these predators used on the sea to catch seal but now the ice level is decreasing rapidly as the temperature is declining.

Sea ice is drifting further north so polar bears travel further to hunt.

Arctic sea ice in December was at its second-lowest level since 1979, according to the National Snow & Ice Data Center.

"Arctic communities are not prepared to deal with such a spill, and when it happens the contaminants will have long-term impacts on important habitat for wildlife, including polar bears, whales and fish", said Paul Crowley, vice president of Arctic conservation for WWF-Canada, in a scorecard that included nation-by-nation evaluations in areas such as management of human and polar bear conflict.

However, it has been hard for scientists to analyze the behavior and fundamental biology of the bears in this harsh and remote environment, according to Pagano. "If they were successful they did quite well". Bears are also doing a lot more swimming as the sea ice declines, said Derocher.

"As the sea ice melts earlier and earlier, polar bears are forced to swim more and more, to reach seal populations", said author Blaine Griffen, a biologist at BYU in a release.

"Nobody can conclude from the study that polar bears will get extinct", he tells DW. She lost 22 percent of her body weight and, worse, lost the nursing cub that had started the journey with her.

IUCN experts estimate that the population could decrease by 30 to 50% if the loss of sea ice continues.


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