Polar bears struggling to find food in Arctic hunting grounds


"You're talking a pretty awesome amount of mass to lose", said U.S. Geological Survey wildlife biologist Anthony Pagano, lead author of a new study in Thursday's journal Science.

The bear videos showed researchers all sorts of usually private aspects of polar bear life, including courtship and hunting.

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.

New information from an American study shows polar bears may be under greater threat from climate change than previously thought.

While scientists were quick to caution that the causes of the animal's condition remain unknown-disease, injury or any number of other factors could potentially have spelled its demise-experts are anxious that starving polar bears may soon become a more common sight as the sea ice they rely on for hunting grounds continues to melt away. They were living on the sea ice of the Beaufort Sea, off the northern coast of Alaska. They're not efficient walkers, but thanks to their high-energy diet of seals they can roam an area as large as 95,000 square miles, Derocher said in an interview.

The study's results, published on 1 February in Science, have captured the best picture yet of how much energy it takes to be a polar bear (Ursus maritimus) - and ecologists are looking to incorporate the findings into their own work on the Arctic. Last month, a video of a starving polar bear went viral, but it is from a different part of the Arctic and unlikely to be related to global warming, Durner said.

Pagano's team studied the bears in a period during April over the course of three years, from 2014 to 2016, in the Beaufort Sea off Alaska.

It had been thought that polar bears could conserve energy by using a "sit and wait" technique, where they hang around a hole until an unsuspecting seal comes along and they pounce on it. By fall, however, young seals are older and wiser, and the bears can not catch as many of them. This causes them to expend more energy during the summer, when they are fasting until the ice returns to the continental shelf in the fall.

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Every year in the Beaufort Sea, the sea ice begins to retreat north in July.

In an average, the metabolic rates of the monitored polar bears were over 50 percent higher than previously predicted by other studies.

Bears can lose weight fast but also gain it back quickly if they can catch seals.

But scientists worry that ongoing climate-driven declines in Arctic sea ice, particularly during the warm months of the year, may be affecting the bears' hunting success.

This research was a collaborative effort led by the USGS and the University of California, Santa Cruz, with contributions by the San Diego Zoo, the Oregon Zoo, Washington State University and Polar Bears International.

Pinning down that figure is an important step in understanding what is happening to polar bears now and in the future with climate change, said polar ecologist John P Whiteman of the University of New Mexico. Researchers also speculated that polar bears could lower their metabolic rate to save energy if they were not successful catching seals, Pagano said. These collars enabled researchers to understand the movements, behaviors, and foraging success of polar bears on the sea ice. It has been hard, however, for researchers to study the fundamental biology and behavior of polar bears in this very remote and harsh environment, Pagano said.

Canada, home to two-thirds of the world's population of roughly 30,000 polar bears, has done a good job surveying subpopulations, making sure the polar bear trade is legally regulated, and incorporating traditional knowledge into polar bear management, the WWF said.