Under the Ice: Understanding the Arctic Food Web

Polar bears
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You may think of the Arctic as a barren wasteland of snow and ice. But there is lots of life thriving in those cold temperatures.

Admittedly, there are fewer animals that have adapted to live in the harsh, cold weather of the Arctic, thus the food chain is relatively simple compared to most ecosystems. Here is a look at the animals that play a major role in keeping the Arctic ecosystem alive.


As in most marine environments, phytoplankton (microscopic animals that live in the oceans) are the key food source for many Arctic species, including krill and fish, species that then become food sources for animals further up the chain. 


Krill are small shrimp-like crustaceans that live in many marine ecosystems. In the Arctic, they eat phytoplankton and are in turn eaten by fish, birds, seals, and even carnivorous plankton. These tiny little krill are also the primary food source for baleen whales.


The Arctic Ocean is teeming with fish. Some of the most common include salmon, mackerel, char, cod, halibut, trout, eel, and sharks. Arctic fish eat krill and plankton and are eaten by seals, bear, other large and small mammals, and birds.

Small mammals

Small mammals such as lemmings, shrew, weasels, hares, and muskrats make their home in the Arctic. Some may eat fish, while others eat lichen, seeds, or grasses.


According to the U.S. Fish & Wildlife Service, there are 201 birds that make their home in the Arctic National Wildlife Refuge. The list includes geese, swans, teals, mallards, mergansers, buffleheads, grouse, loons, osprey, bald eagles, hawks, gulls, terns, puffins, owls, woodpeckers, hummingbirds, chickadees, sparrows, and finches. Depending upon the species, these birds eat insects, seeds, or nuts as well as smaller birds, krill, and fish. They may be eaten by seals, larger birds, polar bears and other mammals, and whales. 


The Arctic is home to several unique seal species including ribbon seals, bearded seals, ringed seals, spotted seals, harp seals, and hooded seals. These seals may eat krill, fish, birds, and other seals while being eaten by whales, polar bears, and other seal species.

Large mammals

Wolves, foxes, lynx, reindeer, moose, and caribou are common Arctic residents. These larger mammals typically feed on smaller animals such as lemmings, voles, seal pups, fish, and birds. Perhaps one of the most famous Arctic mammals is the polar bear, whose range lies primarily within the Arctic Circle. Polar bears eat seals - usually ringed and bearded seals. Polar bears are the top of the Arctic's land-based food chain. Their biggest threat to survival is not other species. Rather it is the changing environmental conditions brought on by climate change that is causing the polar bear's demise.


While polar bears rule the ice, it's the whales that sit at the top of the Arctic's marine food web. There are 17 different whales species - including dolphins and porpoises - that can be found swimming in Arctic waters. Most of these, such as gray whales, baleen whales, minke, orcas, dolphins, porpoises, and sperm whales visit the Arctic only during the warmer months of the year.

Three species (bowheads, narwhals, and belugas) live in the Arctic year-round. As mentioned above, baleen whales survive solely on krill. Other whale species eat seals, seabirds, and smaller whales.