Climate change is making polar bears go hungry, study finds

Feb 02, 2018, 21:13
Climate change is making polar bears go hungry, study finds

Scientists observed the metabolism of nine female polar bears every spring from 2014 until 2016 in the Beaufort Sea, tracking their size and weight as well as various metabolic indicators from blood and urine samples. Eight to 11 days later they were all re-captured.

"We wanted to understand what the basic mechanisms were, what the polar bears were doing on the ice and what their energy needs are".

USGS researchers' most recent estimate of the polar bear population indicates their numbers have declined by 40% over the past decade, but a common problem for researchers is that it has been hard to study polar bear behavior in these harsh environments, Pagano said in a statement. Their energy consumption as calculated during the study was 1.6 times higher than previously thought.

Over the course of the study, four of the nine seals did not reach that calorie level and lost a combined mass of 20 kilograms (44 pounds), which "reinforced the starvation lifestyle the polar bears have", Pagano said.

While the recent study might be bad news, it doesn't automatically mean the end for polar bears, comments Jörns Fickel, a evolution geneticist at the Leibniz institute for Zoo and Wildlife Research in Berlin.

The cameras recorded footage of bears catching seals and hauling them out of the ice, as well as of bears wrestling with large seals in frigid waters.

A polar bear rests on a chunk of sea ice in the Arctic.

It also showed that bears will spend more time moving around because of melting sea ice - which is declining at a rate of 14% per decade - and that is likely to have a negative effect on their populations. "They need to be catching a lot of seals", Pagano said.

Fickel points out that the species has seen many warmer periods during their existence, and that they might be able to adjust to a warmer world - as long as there is a healthy seal population, that is.

"No sea ice, no polar bears, it's really simple", said Dr. Bechshoft.

The farther the bears have to travel to get on the ice to hunt the more weight they lose.

Polar bears could be sliding towards extinction faster than previously feared, with the animals facing an increasing struggle to find enough food to survive as climate change steadily transforms their environment.

Best estimates say there are 20,000 to 30,000 polar bears in 19 different groups or populations scattered across the top of the U.S., Canada, Greenland, Norway, and Russian Federation.

"Pretty much every component they've found was largely confirmatory in nature", Derocher said. While the decline has been easy to observe, the causes have been more elusive, given the remote areas the bears inhabit.

"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.

Previous studies estimate the mortality of male polar bears would increase from 6 per cent to 48 per cent if fasting periods increased from 120 days to 180 days. "I don't know if that poor bear in that video was starving".

If you've ever wondered what it's like to be a polar bear rambling about the freezing areas near the arctic circle, now you can - thanks to this wonderful video captured on a point-of-view camera.