Ancient frigid bears survived low ice durations by scavenging passed whales: study
New investigate suggests an answer to a poser of how frigid bears survived prior eras of low sea ice.
But a same paper, published Tuesday in Frontiers of Ecology and a Environment, says a bears aren’t expected to be means to rest on a same resolution again.
“I don’t consider we can assume what worked in a past is going to work in a future,” Kristin Laidre of a University of
Washington, who co-authored a paper with Ian Stirling from a University of Alberta.
Genetic investigate says frigid bears diverged from other bears during slightest 150,000 years ago. That means a class lived by several low-ice periods, including a vital comfortable duration about 130,000 years ago.
At that time, while some year-round sea ice is suspicion to have remained, sum coverage was severely reduced and mostly found in a really top reaches of a Arctic. Despite a bears wanting sea ice to hunt fat-rich seals, somehow they survived.
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Laidre and Stirling posit those long-ago bears done it by an extended duration of low ice by scavenging whale carcasses cleared adult on Arctic beaches.
“Polar bears expected survived those durations by accessing stranded sea reptile carcasses, and many expected vast whale carcasses,” Laidre said. “They’re such vast carcasses that they can be packages of food for, in some cases, years.”
The researchers distributed that a race of about 1,000 bears would need about 20 bowhead whale carcasses to sojourn healthy by a open foraging deteriorate and about 8 carcasses during a summer, when a bears eat less.
‘Hopefully, we’ll get meridian warming underneath control’
They afterwards looked during mankind rates of vast whales and what commission of them competence boyant prolonged adequate to rinse adult on a beach.
Those numbers matched good with celebrated numbers of whale carcasses found in several tools of a Arctic.
A widen of Russian seashore along a Chukchi Sea, for example, averages about 10 carcasses a year between Jul and November. A tiny series of frigid bears have schooled to rest on that resource.
The numbers advise that washed-up whales could have been during slightest a vital addition during bad sign sport conditions — generally given frigid bears are really good during feasting on and storing fat.
“I consider they were really expected a categorical source of nutrition,” pronounced Stirling.
The destiny of complicated frigid bears in a face of fast timorous sea ice is most debated, with some arguing their presence by prior low-ice durations bodes good today.
Laidre and Stirling aren’t so sure.
The gait of change is most faster currently than in a past. Bears don’t have most time to learn new behaviours on a far-reaching scale.
As well, there aren’t as many whales as there used to be.
“Most of a whale populations have been overharvested,” Stirling said.
At best, he pronounced whale carcasses could buy bears a small some-more time.
“We might have a small bit longer timeline. Hopefully, we’ll get meridian warming underneath control.
“For a several opposite class that count on a frigid ice ecosystem, we might be means to keep some of that in the healthy condition.”
Article source: https://www.cbc.ca/news/canada/edmonton/polar-bears-survived-low-ice-by-scavenging-whale-carcasses-1.4856011?cmp=rss