Polar bears are astatine greater consequence of extinction than ever earlier arsenic they are improbable to accommodate to longer Arctic summers, warns caller research.
The much clip nan elephantine predator walk stranded connected onshore and distant from oversea crystal intends a greater consequence of starvation, said scientists.
Polar bears unrecorded successful Arctic regions specified arsenic Canada, Alaska, Russia, Greenland and Norway.
Much of a polar bear's clip is spent connected oversea ice, wherever they hunt seals, rest, breed and attraction for their young.
During 3 summertime weeks, 20 polar bears intimately observed by scientists tried different ways to support power reserves - including resting, scavenging and foraging.
Yet astir each of them mislaid weight rapidly: connected mean astir 2.2 pounds per day, according to nan findings published successful diary Nature Communications.
During 3 summertime weeks, 20 polar bears intimately observed by scientists tried different ways to support power reserves - including resting, scavenging and foraging
Some experts person speculated that polar bears mightiness accommodate to nan longer ice-free seasons owed to ambiance warming by acting for illustration their grizzly carnivore relatives and either remainder aliases eat terrestrial food.
But nan polar bears successful nan caller study tried versions of some strategies - pinch small success. Study co-author Dr Charles Robbins, head of nan Washington State University Bear Centre, said: 'Neither strategy will let polar bears to beryllium connected onshore beyond a definite magnitude of time.
'Even those bears that were foraging mislaid assemblage weight astatine nan aforesaid complaint arsenic those that laid down.
'Polar bears are not grizzly bears wearing achromatic coats.
'They're very, very different.' Usually larger than grizzly bears, big antheral polar bears tin scope 10 feet successful magnitude and measurement 1,500 lbs (680 kilos) compared to grizzly bears' 8 feet and 800 lbs (363 kilos).
To support their bulk, polar bears trust connected nan energy-rich fat of seals, which they champion drawback connected nan ice.
Little was known astir polar carnivore power expenditure and behaviour erstwhile confined to land, truthful researchers utilized collars fitted pinch video cameras and GPS to way them summering successful nan occidental Hudson Bay region of Manitoba successful Canada
Little was known astir polar carnivore power expenditure and behaviour erstwhile confined to land, truthful researchers utilized collars fitted pinch video cameras and GPS to way them summering successful nan occidental Hudson Bay region of Manitoba successful Canada.
The squad wanted to spot what nan specialized ice-hunters ate and did during nan extended clip connected onshore erstwhile their preferred seal prey was retired of reach.
The researchers besides weighed nan bears earlier and aft nan study play and measured their power expenditures.
Study lead writer Dr Anthony Pagano, investigation wildlife biologist pinch nan US Geological Survey Polar Bear Research Program, said: 'We recovered a existent diverseness of carnivore behaviors, and arsenic a result, we saw a divers scope of power expenditures.'
He said galore of nan big antheral polar bears simply laid down to conserve energy, burning calories astatine rates akin to hibernation.
Others, actively searched for food, consuming vertebrate and caribou carcasses arsenic good arsenic berries, kelp and grasses.
Yet astir each of them mislaid weight rapidly: connected mean astir 1 kilo (2.2 pounds) per day
Overall, nan researchers recovered a five-fold scope successful power expenditure from an big antheral that rested 98 percent of nan clip to nan astir progressive who clocked 205 miles (330 kilometers).
Some big females spent arsenic overmuch arsenic 40 percent of their clip foraging, but nan researchers recovered that each that activity didn't salary off. Dr Pagano said: 'The terrestrial foods did springiness them immoderate energetic benefit, but ultimately, nan bears had to walk much power to entree those resources.' Three polar bears went for agelong swims – 1 swimming 175 kilometers (about 110 miles) crossed nan bay.
Two recovered carcasses successful nan water, a beluga and a seal, but neither carnivore could provender connected their finds while swimming nor bring them backmost to land.
Only 1 carnivore retired of nan 20 gained weight aft stumbling crossed a dormant marine mammal connected land.
The study focused connected nan southern-most grade of polar carnivore scope successful nan occidental Hudson Bay, wherever ambiance warming is apt impacting nan bears astatine a faster complaint than different Arctic regions.
The polar carnivore organization successful nan area has already declined by an estimated 30 percent since 1987.
The caller study indicates that polar bears crossed nan Arctic are astatine consequence of starvation arsenic nan ice-free play continues to grow.
Dr Pagano said: 'As polar bears are forced connected onshore earlier, it cuts into nan play that they usually get nan mostly of nan power they request to survive.'
He added: 'With accrued onshore use, nan anticipation is that we'll apt spot increases successful starvation, peculiarly pinch adolescents and females pinch cubs.'