polar bears can not find enough seals to get satiated and the problem is going to get worse with climate change according to a study on Thursday showing that the King of Pack ice's metabolism is higher than estimated.
"We have discovered that polar bears actually have much higher energy needs than expected," said Anthony Pagano, the lead author of this study published in the journal Science.
"They need to catch a lot of seals" to satisfy a metabolism 1.6 times higher than that put forward by previous estimates, according to this scientist from the University of Santa Cruz in California.
Biologists followed nine females in the Arctic in the Beaufort Sea, equipping the plantigrades with camera-collars and comparing their urine and blood samples several days apart.
The study took place "at the beginning of the period from April to July when polar bears hunt the most actively and store the fat they need to subsist all year round," said Pagano, who works also for the United States Institute of Geological Studies (USGS).
And despite this, five specimens lost body mass within 8 to 11 days. "Four bears lost 10% or more of their body weight," says the report.
Previous hypotheses had misled scientists about the metabolism of these huge mammals.
Researchers thus thought that their hunting technique, which essentially consisted of waiting for the prey, led them to spend little energy to feed themselves. Or they could slow down their metabolism when they did not catch enough seals.
The Arctic is warming twice as fast as the rest of the world and melting ice forces bears to travel further to find the young seals that are their favorite food.
"Ice across the Arctic is decreasing by 14% per decade, which is likely to reduce bears' access to their prey," says the study.
The polar bear population has declined by about 40% over the past decade, according to the USGS. But "we now have the technology to study their movements on the ice, their activities and energy needs, and we can better understand the implications of the changes we see on the ice," reassures Anthony Pagano.
SOURCE : www.lapresse.ca
