Wherever I’ve traveled in the world, I have always been fascinated by what humans and other species eat. With a background in animal behavior and food anthropology, I traveled to the Polar Bear Capital of the World with a curiosity about the diets of people and animals living in this remote portion of the subarctic. What I found was that subsistence lifestyles in Churchill were intrinsically interlinked with wildlife and their food sources. We spoke with a trapper who lived 60 miles outside of town and detailed his immersion in the boreal forest, from dogsledding past caribou herds browsing on willows to hunting snow geese. We next learned about the traditional foods of indigenous people during a visit to the Inuit Museum. Our guide, an Arctic anthropologist, showed us carvings of hunting scenes on walrus ivory, narwhal tusks, caribou antlers, muskox horns and whalebone vertebrae, as well as a ringed seal pelt. These animals provided food, clothing and tools for people living in the north. Marine mammals were an essential part of the traditional diet, and these blubbery creatures also serve as the polar bears’ main source of sustenance. Each autumn near Churchill, polar bears congregate along Canada’s Hudson Bay in anticipation of the freeze-up to begin the annual polar bear seal hunt.
Of the eight bear species, polar bears are the most carnivorous, relying primarily on seals to survive. These sea bears, whose scientific name is Ursus maritimus, are at home on the ice, seeking out seals in frigid waters. They keep silent watch over breathing holes in the ice pack, waiting patiently for hours on end for a seal to surface for air in a practice called “still-hunting.” Polar bears also stalk seals while they rest, molt or care for their young on the ice. Once a seal is spotted, the bear crouches and creeps forward until it makes an explosive pounce from 30 to 40 feet away, catching the pinniped in its jaws before it slips back into the sea. Polar bears also locate seal pup birth lairs with their keen sense of smell, breaking through the snow roofs with their powerful paws.
While ringed and bearded seals are the polar bears’ primary targets, they also hunt harp, hooded and ribbon seal when available. Where seals are plentiful, the polar bears eat only the fat of the animal, leaving the rest for scavengers such as foxes, ravens and other bears. A polar bear can devour up to 150 pounds of food in one sitting but must capture a seal once every five to six days to maintain its body weight.
While traveling over the tundra, our Expedition Leader gave an overview of the Arctic food web, which offered us insight into how every creature in this far northern land is connected. Ice-adapted algae grow on the underside of the ice, which krill feed upon. Arctic cod and other fish species eat the krill, which are in turn consumed by ringed seals, the most abundant seal in the Arctic and the primary prey of polar bears. If one link in this cycle is broken, the entire marine food chain is at risk.
Bears are opportunistic feeders, and will occasionally hunt more difficult prey such as beluga whales, narwhals and walrus. Polar bears can detect a carcass from nearly 20 miles away with their extraordinary sense of smell and will feed on the bodies of beached bowhead whales and other remains. They’ll also eat fish, shellfish, waterfowl, eggs, rodents and hares. Larger land mammals such as caribou and muskox are difficult to catch, as polar bears overheat quickly due to their thick coats, but they stand a better chance when targeting a young or sickly animal. Polar bears will investigate human garbage dumps if they are not properly secured—Churchill closed its landfill in 2006 due to this problem, and now trash is transported outside of town.
Bright jewels dot the tundra in the form of bearberries, bilberries, bunchberries, cloudberries, cranberries, crowberries, dewberries, gooseberries and lingonberries. Bolete mushrooms grow wild alongside mosses, lichens, roots, grasses and sedges. During the summer thaw, polar bears supplement their diet with berries, fungi and plants, as well as kelp from along the coastline. These alternative foods, while adding variety to the polar bear’s diet, do not provide sufficient caloric intake to keep the bears from losing weight. Since these resources are simply not enough to sustain these large carnivores long-term, polar bears subsist mainly off their stores of fat until they can regain these reserves during the winter seal hunt.
The polar bear’s way of life is entirely dependent on sea ice. The Society for Marine Mammalogy states that “the polar bear’s metabolism is specialized to require large amounts of fat from marine mammals,” but climate change is already disrupting this regal predator’s hunting patterns.
A warming planet spells disaster for the King of the Arctic. As rising temperatures cause the ice pack to form later in the season and break up earlier, the bears’ fasting period stretches, and their energy stores become further depleted. The future of the polar bear is in our hands. You can help by supporting organizations like World Wildlife Fund, which advocates for the protection of this noble bear and the preservation of its Arctic habitat.