Polar bears forced to feed eggs as hunting grounds gather as they heat up: a study

Some bears also come ashore at the same time as seabirds nest and nibble their eggs.

Hungry polar bears are increasingly looking for seabird eggs as climate change shrinks their Arctic hunting grounds, but research published Wednesday on the phenomenon highlights a struggle these supreme predators must adapt to their rapidly changing environment.

The threat of climate change for polar bears is well known, driven by the extraordinary pace of change in the Arctic, which is warming twice as fast as the planet as a whole. This is already leading to a reduction in sea ice, shortening the time required to hunt seals, their favorite prey.

With the growing imperative of finding alternative food, polar bears have been pushed further in search of food, including cleaning in populated areas.

Some bears also come ashore at the same time as seabirds nest and nibble their eggs.

To measure how effective these predators were at the top of the food chain – and therefore how useful eggs are for providing energy in the diet – researchers in Canada used drones to monitor them feeding from goose duck nests on Mythic Island, in Nunavutu.

Inefficient hunting

Study, published in the journal The open science of the Royal Society, monitored how the bears approached the nesting site over a period of 11 days as the number of eggs was depleted.

“We found that bears that arrived later increasingly visited empty nests and did not travel in a way that reduced energy, but became less picky in the claws they consumed,” said lead author Patrick Jagielski of the Lakes University Institute for Large Research. Windsor.

The bears also did not consistently realize that the sudden appearance of a fleeing hen meant that the eggs were nearby.

“This study shows that although species are able to include‘ less preferred ’resources in their diet when it is more difficult for them to obtain primary prey, they may not be able to do so efficiently,” the authors said.

Jagielski said AFP that research cannot speak more broadly about the ability of polar bears to cope with climate change, but has raised questions about the energy value of eggs as an alternative food source.

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‘Extinction event’

Today, approximately 25,000 Ursus maritimus remain in the wild in 19 population subgroups distributed throughout the Arctic in Alaska, Canada, Greenland, Norway, and Russia.

A study published in was published in July Climate change in nature he estimated that the species would starve by 2100.

Researchers also looked at climate heating predictions and data about an increasing part of the year that bears must survive on their fat reserves.

Earlier this month, a paper published in a journal Global Change Biology found that polar bears maintained a highly specialized diet of soft fat and meat for hundreds of years – even during previous periods of Arctic warming.

Researchers from Vanderbilt University, who examined tooth wear on skulls in museums, said polar bears are so specialized in their diet that they may struggle to adapt to Arctic warming.

But they said an increase in the number of encounters with grizzly bears could provide one evolutionary option, noting incidents in which two species gave birth.

Jack Tseng of the University of California, Berkeley, said in a related commentary that the fate of the polar bear is ultimately “inextricably linked” to the way it drives momentum toward a “turning point” for the Earth’s flora and fauna. “Will polar bear populations need to rely on hybridization with grizzly bears as a means of adapting to a changing environment,” said Tseng, who was not included in the study. “Will they successfully reorient their hunting strategy to reduce competition with sister species or will they become another victim in an ongoing extinction event that is accelerating in this century?”