Witnessing Summer Starvation Among Polar Bears (Pics)
Polar bear hunting the northern ice pack; All images by Rebecca Jackrel
Summer on land is a difficult time for polar bears. Relying on the fat gained during winter hunting to see them through the more difficult hunting of summer when pack ice melts. Unfortunately, summer is becoming even deadlier, with pack ice melting earlier, melting farther, and arriving later in the winter. Rebecca Jackrel made a trek to Svalbard, a mecca for polar bear viewing, during July. She witnessed many of the problems polar bears are struggling against during summer months. Check out the outstanding photos from her journey. Jackrel states, "When summer comes to Svalbard the ice pack melts and polar bear are stuck on land. Their metabolism slows down and they enter a kind of walking hibernation. They rely on the reserves of fat generated from a winter of hunting seals to sustain them through the summer months. Polar bear are at their most dangerous to humans at this time of year... wouldn't you be if you were starving?"
Not only are polar bears more dangerous to humans at this time of year, but the odds of running into one have been increasing in conjunction with melting ice. The less ice, the more likely polar bears are to be on land, and near human habitations.
Not only are bears coming into contact with humans more, but also into contact with other prey species they might not normally bother with.
Bearded Seal - one of the meals of choice for a hungry polar bear
Being stranded with fewer food choices for longer periods during summer is becoming a problem for migratory birds as well. As David wrote last summer, the Barnacle Geese that nest on Svalbard during summer are increasingly a target for polar bears. Even though their eggs are small in comparison to a bear's usual meal for a bearded seal (shown above), they're easy food. Period. And the slow-to-reproduce birds are losing thousands of eggs to hungry bears.
"Indeed, the impact has not been insignificant. Of the more than 500 nests holding eggs on the island this summer, fewer than 40 were successful--with the majority of those producing only one or two chicks. Just 60 years ago, the goose population on Svalbard had dipped below 300. After decades of conservation work, the population has climbed above 30,000. This most recent threat, however, could jeopardize that seemingly robust number."
When pack ice melt presents problems for bears, the effects trickle out to other species as well.
Polar bear on a seal kill on the northern ice pack
However, there is still some food to be had during summer, as evidenced by this bear polishing off a seal kill. Polar bears rely mainly on seals -- primarily ringed and bearded seals. However, it takes ice to catch a seal.
While polar bears are excellent swimmers, seals can dance circles around them in the water and it is rare that a bear can catch one in the open ocean. Bears mainly catch seals when they come up to breathe through a hole in the ice or haul up onto the ice to rest.
In the summer, when the ice is melted, the opportunity to catch seals is few and far between, which is another reason why bears enter this fasting period in late summer and fall. If they didn't catch enough seals in winter, they won't have enough fat to sustain them -- and with ice melting sooner and arriving later, it's a serious problem.
A few weeks into summer the ice pack begins to melt, bear need to swim further to find ice to hunt seal. Eventually the ice is too far for them to reach so they retreat to shore.
Some of the most heartbreaking images are that of polar bears without any ice to rest on. The record-breaking swims have become news headlines. Earlier this year, a bear was seen to swim 426 miles over 9 days without a single rest. This uses up their valuable fat reserves, which they can little afford to waste on long swims.
Even mother bears have been spotted swimming with their cubs on their backs, a situation that is both good and bad -- good, because it shows adaptive behavior that could help cubs' odds of surviving the swims, but bad for the obvious reason that it saps a mother's strength and her own fat reserves, which can in turn reduce a cub's chances of making it to adulthood.
It's uncertain why this bear perished but his teeth showed him to be a young bear, possibly newly turned out from his mother. His body shows signs of severe emaciation. It's possible that he just wasn't able to find enough food to sustain himself.
Some bears succumb to the lack of food. Though the bears are clever, powerful, and skilled at hunting, when there is not enough food or enough ice to hunt, there is little that can save them.
When the IUCN added polar bears to the vulnerable species list in 2006, it "cited a 'suspected population reduction of >30% within three generations (45 years)', due primarily to climate change."
However, starvation from loss of pack ice is not the only threat. "Other risks to the polar bear include pollution in the form of toxic contaminants, conflicts with shipping, stresses from recreational polar-bear watching, and oil and gas exploration and development. The IUCN also cited a "potential risk of over-harvest" through legal and illegal hunting."
This bear discovered an island full of nesting birds. It's easy pickings for a polar bear but barely makes a dent in their nutritional requirements.
Another concern among scientists for the future of polar bears comes with its increase appearance on solid land, which leads to interactions with competitors. While the polar bear is in a class of its own as a hunter on the ice, on land there is competition -- brown bears.
A study conducted by UCLA last year noted that while both grizzly bears and polar bears have similar bite strength, a polar bear's skill is weaker than that of a grizzly, leading the team to believe that in a fight, a grizzly bear may be more likely to survive.
However, not all interactions between polar bears and brown bears lead to fights -- they sometimes lead to reproduction and hybrids called growler bears or pizzly bears, depending on your preference. They hybrid might not be that original however, since research has shown that all modern polar bears today may well be descended from interbreeding with a now-extinct brown bear species found in Ireland about 20,000 years ago.
As brown bears move north to escape warming climates and polar bears seek land to escape from the open sea, run-ins are bound to happen more often. Whether the ultimate outcome is a hybrid of the bears or deadly conflict is yet to be determined.
Not as good as pack ice but the calving glaciers in Svalbard offer ice for seal to haul out on which makes a good hunting ground for the bear while they wait for winter to reform the pack ice.
While the outlook for polar bears is dire, there is some hope. Some researchers are rooting for polar bears to adapt to new strategies for hunting and new food sources. The odds of quick adaptation are slim, but there is that slim possibility. Meanwhile, government officials could help by moving the bears from threatened to endangered status, which would provide new protections for them, including protection from hunting which is still legal in Canada.
If you'd like to find out more about what you can do to help protect polar bears, we recommend checking out WWF's polar bear conservation website.
Meanwhile, check out more incredible photos of polar bears on Rebecca Jackrel's website. Jackrel is a conservation photographer who makes treks from Svalbard to Churchill and more to photograph these incredible icons of the north.
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