When a polar bear kills, it doesn’t just eat. It feeds a whole ecosystem

When a polar bear kills its prey, it is not the only one who reaps the bloody rewards.

Many of nature's top predators guard their dinner from scavengers until they have devoured every last piece and licked the bones. But scientists say Arctic leopards tend to eat what they need and leave the rest for other Arctic creatures to eat.

New research published the magazine OikosScientists estimate that one polar bear provides approximately 300 kilograms of meat per year for other animals. Considering there are 26,000 polar bears in the Arctic, that's a whopping 7.6 million kilograms of food per year.

“If we lose polar bears from the Arctic … nothing can replace that,” said Holly Gamblin, a wildlife biologist at the University of Manitoba. How it happens presenter Neil Koksal. “There is no other species like it that does this.”

Sharing is not necessarily caring.

By sharing the spoils of a hunt, polar bears provide what's called an “ecosystem service,” Gamblin says. lead author of the study. AAnd this is in stark contrast to the behavior of many other predators, such as cougars and wolves.

But polar bears, she says, do not do this out of the kindness of their hearts.

“I can’t say they have that altruistic nature,” she said. “But what they have is a special diet for fat.”

Polar bears only really want to eat one thing, she says, and that's blubber, the thick layer of warming fat under the skin of marine animals such as seals and penguins.

“They usually take it off first,” Gamblin said. “They don't really care about the leftover meat. They have a hard time digesting that protein.”

Jeff York, polar bear researcher who did not participate in this study, withYes, polar bears will go for fat if they're hungry enough, but they definitely prefer those fatty bits.

“Just as brown bears along salmon streams become more selective as they gain weight, eating only the eggs of spawning salmon and leaving the carcass behind, polar bears in good physical condition also focus on the fat of marine mammal prey,” said York, director of research for the conservation group Polar Bear International, in an email.

And one Arctic predator's trash is another's treasure.

The study, which included scientists from the University of Alberta, confirmed that 11 vertebrate species have been documented feeding on discarded polar bear meat, including wolves, foxes, gulls, hawks, snowy owls and grizzly bears.

The team also identified eight more species as potential scavengers because they had been observed on sea ice but had not been studied. observed a polar bear eating waste.

Chief among the benefactors are Arctic foxes, who have been known to follow polar bear tracks onto the sea ice in hopes of catching some scraps of meat.

“Arctic foxes are considered polar bears’ best friends,” Gamblin said. “So polar bears foraging and fattening may actually be influencing the Arctic fox population from year to year.”

But the polar bear population is rapidly declining.

One study last year estimated that Polar bears may disappear completely from Hudson Bay over the next few decades due to melting sea ice as a result of climate change.

Gamblin and her colleagues note that polar bear populations declined by 32 percent in the western Hudson Bay between 1987 and 2011 and by 44 percent in the southern Beaufort Sea between 2004 and 2016.

According to the study authors, these losses alone amount to 323,000 kilograms of lost food resources for other Arctic animals.

“This is another reason why protecting polar bears is so important,” York says.

“The potential loss of top predators is not the loss of one species, but the loss of a key player in the ecosystem, which will have a domino effect throughout the Arctic,” he said.