Climate change diet: As Arctic sea ice thins, so do polar bears

Climate change diet: As Arctic sea ice thins, so do polar bears

Climate change diet: As Arctic sea ice thins, so do polar bears

Retreating ice sheets, a result of climate change, are forcing the bears to travel greater distances to find the food they need, which in turn causes them to expend more energy than in the past, the study said.

Lead scientist, Anthony Pagano, does note that the findings of the Beaufort Sea shouldn't necessarily be expanded to the other 18 circumpolar populations of bears where he says, conditions can differ for each group.

"There can be multiple fasting periods in the polar bear cycle and those fasting periods are growing longer as a result of climate change".

Mr Pagano and his collaborators monitored the behaviour, hunting success and metabolic rates of bears as they hunted on the sea ice in the spring.

The researchers used high-tech collars on the bears to record video, locations and activity levels over a period of eight to 11 days.

This means the bears must kill and eat more seals over the course of a year, to pay for this higher metabolic rate. Bears in the Beaufort Sea region are among the best studied and their numbers have fallen 40 percent in the last ten years.

This is where there's still a lot of work to be done, the WWF said.

Analysis of the bears' metabolism revealed they required at least one seal every 10 days to satisfy their dietary needs, but numerous bears were unable to capture enough.

Millions have seen the heart-wrenching video of a polar bear clinging to life, its white hair limply covering its thin, bony frame. He's been studying locomotion and metabolism in polar bears, including captive bears at the Oregon Zoo, for more than 10 years. The four bears that lost significant amounts of weight had been unable to catch any seals.

But still, "when I see pictures of big glacial blocks breaking away and the sea ice is retreating, I get anxious", Fickel admits.

From blood and tissue samples taken at the start and end of the research, scientists discovered the bears' metabolic rate is about 60 per cent greater than previously believed. "And if they don't do that they're going to lose weight".

"If it's bad for polar bears, it might be affecting us in other ways - us being humans", Durner said.

Meanwhile, the most recent polar bear population estimate by USGS also indicated almost 40 percent decline over the past decade. These Arctic mammals need a lot more calories than scientists previously estimated - but with sea ice melting under their feet, the bears often struggle to get enough to eat.

Photos of skinny and emaciated polar bears are more common as their food disappears

Unfortunately, with the rapid environmental changes occurring in Arctic sea ice, the specialisation that once allowed polar bears to live in this challenging habitat has painted the animals into a physiological corner and led to devastating consequences.

Globally, the polar bear population is thought to be holding roughly steady at around 25,000-30,000, Andrew Derocher, who has studied the species Canada's University of Alberta since the 1980s, told Seeker.

The loss of sea ice has a domino effect on the species, which, in 2008, became the first animal listed under the Endangered Species Act due to threats from climate change. "Activity and movement on the sea ice strongly influenced metabolic demands", the researchers summarized in the abstract of their paper.

In other areas like Hudson Bay, the sea ice is breaking up earlier in the summer and returning later in the fall, which has forced the polar bears to spend more time on land. The remote location has made it hard for scientists to study the bears' movement and activities until now.

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