The Arctic Fox or Vulpes Lagopus, as we have all known them to be, is a snow-white fox (at least during the winters) that inhabits the Arctic regions, or in layman terms, most places in the Northern Hemisphere that are cold. Barely the cat’s size, they are excellent hunters and prey on a number of creatures, generally lemmings, voles, and insects. However, they also often eat berries and other fruits when available seasonally.
These master camouflagers, with color morphed coats, barely the size of a cat, have a lot of science going behind what they eat other than what we see on the surface.
Below is all about what they eat, how they hunt, and the adaptations that help them in finding food.
Where are Arctic Foxes found?
Arctic foxes are found throughout the arctic tundra biome in the northern hemisphere.
Habitat and Range
Arctic Foxes live in different habitats, including Arctic, alpine tundra, coastal areas, and ice floes. Initially, in the 19th century, they were introduced in the Aleutian Islands southwest of Alaska. However, today their population mostly inhabits tundra and pack ice, and in Canadian boreal forests and Kenai Peninsula.
The circumpolar range of the Arctic Foxes is found in the tundra regions along the northernmost regions of Europe, Asia, North America, Svalbard, Jan Mayen, Fennoscandia, Greenland, and Iceland. They can also be found in the Western Alaska east all the way through northern Canada, which includes some portions of Alberta, Manitoba, and Quebec. They are found on other islands of the Bering Sea, Hudson Bay, Barents Sea, and northern Russia.
Migration
Arctic Foxes from Alaska migrate from their fall breeding grounds to coastal areas, returning in late winter and early spring. The lack of food supply is probably the reason for their large-scale migration, which is recorded in Canada, Russia, and the Scandinavian peninsula.
The Arctic Foxes living near the coastal areas, including the goose colonies, are less likely to migrate. Only those foxes migrate who experience low-density lemmings populations. The mortality rate of the migratory foxes is greater than three times compared to resident foxes.
What do Arctic Foxes Eat? (full list)
An Arctic Fox’s diet changes over the year – it is seasonal (which we will talk about further below in the post). Here is a full list of what an arctic fox eats:
Animals
- Seabirds, Birds, and Eggs: Arctic foxes, mainly those in the coastal regions, feed on a variety of seabirds, birds, and, most importantly, their eggs. These birds are:
- Ducks
- Loons
- Geese such as Cackling Canada Geese, Pacific White-Fronted Geese, and Emperor Geese, Black Brant Geese,
- Gulls such as Glaucous gulls, Sabine’s gull, and mew gull
- Northern Pintail
- Puffins
- Loons such as Pacific loons and red-throated loons
- Greater Scaup
- Arctic terns
- Grouse
- Auklets
- Northern Shoveler
- Moores
- Waterfowl
- Shorebirds such as sandpipers, black turnstones, red-necked phalaropes, parasitic jaegers, Lapland longspurs, savannah sparrows, and willow ptarmigans.
- Arctic foxes eat eggs of the tundra nesting birds whenever possible.
Terrestrial Animals:
Arctic foxes eat reptiles, amphibians, mammals, small insects, worms, and small invertebrates in the wild. These Arctic Fox preys are listed as:
- Lemmings, brown lemmings, and collared lemmings. These make for the arctic fox’s favorite part of the diet and the most abundant one too. These small, short-tailed rodents are highly available throughout the arctic tundra biome, which makes them the most consumed arctic fox food.
- Voles and tundra voles
- Ringed Seal pups that are confined to their dens
- Mink
- Hares including arctic hares and tundra hares
- River otters
- Beavers
- Masked shrews
- Meadow jumping mice
- Muskrats
Fishes and Marine Invertebrates:
After all, they are the distant relatives of cats! Arctic foxes prey on fishes and are great swimmers. Here is a list of the marine creatures arctic foxes feed on:
- Shellfish
- Mussels
- Urchins
Fruits and plants
Arctic foxes are omnivores, and fruits are considered a crucial part of their diet. During winters, or whenever available, arctic foxes feed on frozen fruits such as berries. Even during the summer, when it gets difficult to catch prey, they eat seaweed and different berries blooming in the habitat.
Carcasses and Carrion:
It often gets tough for the arctic foxes to find food in the winters. It is then that they eat over the leftover carcasses and the carrion left by other animals. Arctic foxes usually follow the apex predator in the ecosystem, the polar bear, and eat the leftover prey hunted by the animal. If the arctic fox accumulates a large amount of meat, it will store it deep in snow to be eaten later.
Arctic foxes eat the carrion and carcasses of large animals such as reindeers, spotted seals, and walruses while also scavenging food from cliffs that are colonies to seabirds.
Other
Arctic foxes harbor a dirty secret – they eat their own waste when necessary. However, the reason behind it isn’t as gross. The waste has leftover nourishment that, if consumed, can still be extracted by digesting it all over again. This not only saves them the energy and time to hunt but also maintains their body salt balance that can sometimes be difficult to keep up with given their harsh habitat.
What do Arctic Foxes Eat in different seasons?
Spring and Summer
Summer is the time when the Arctic Foxes start collecting enough food and store it in their den. During this period of time, they prey mostly on ringed seal pups. Being an omnivore, they also consume berries and seaweed; they are significant bird egg predators consuming all types of bird eggs.
They aim to consume a large amount of food which forms a thick fatty layer of fat on their body, and prepare themselves for winter. Arctic Foxes don’t hibernate. Hence they need to put on weight during summer and spring in order to tolerate the cold winter.
Foxes from eastern Iceland switch diets from ptarmigans, snow buntings, and carcasses to migrant birds like geese, waders, and passerines in spring. The inland foxes primarily depend on the migrating and resident birds, commonly ptarmigan. According to the isotope analysis, eggs can be stored and eaten after a year, and the metabolizable energy of a goose egg is decreased by only 11% after 60 days.
Winter
Winter is the harsh time of the year when there is a scarcity of food for the Arctic Foxes. It is during this time when they depend on their stored body fat or hoarding body fat in order to survive. Seabirds and their eggs are a primary source of food for the Arctic Foxes, and they are often found feeding on mussels.
While in the coastal areas, they get carcasses of marine mammals, birds, fish, waders, and other invertebrates. In winter, they find it difficult to search for food since they don’t hibernate. Hence, in winter, they use the food that they buried or stored underground during summer and spring when meat is not readily available in the ice tundra.
They feed on ringed seal pups helplessly remaining in their dens, and they hunt as many pups and animals as they can. They can also be found eating frozen berries and insects in extreme winters. They track animals like polar bears and wolves to find the remains of their kill and feed on carcasses of reindeer and other animals.
At the beginning of winter, an average Arctic Fox has approximately 14800 kJ of energy stored in the form of body fat. According to the lowest BMR value, an average-sized fox requires 470kJ/day during winter to survive. They acquire goose eggs at a rate of 2-7 eggs/h and store 80-90% of them for winter. Seabirds are a significant source of food for the western Icelandic Arctic Foxes, available throughout the year.
Marine invertebrates such as mussels, crustaceans, mussel shells, and beached seal carrion leftover by polar bears also make for feasts for arctic foxes during the winter. The Arctic Foxes, mostly from northern Canada, catch and consume a significant number of migrating seabirds when there is a scarcity of ground prey in winter.
How do Arctic Foxes Hunt?
Arctic foxes have certain physical adaptations that help in finding food, such as sharp hearing, color morphs to blend in with the landscape, and the ability to focus on the moving prey.
Generally, when hunting a lemming, the arctic fox stills completely and then tilts its head towards the direction from where it can hear the prey’s movement. To pinpoint the lemming’s steps and location, the arctic fox stands its ears to utmost attention and, once located, slowly zeroes in on the prey.
Once it has the lemming in sight, it plunges on it from the top, headfirst, with a wide-open mouth ready to grab the prey by the neck.
This ambush from above, known as ‘mousing,’ gets the arctic fox its prey. Tada! A great win!
Arctic Foxes’ Adaptations for finding food and survival in the snow
The mesmerizing snowy creatures have evolved over the course of time and have quite a few adaptive features that help them survive the arctic conditions and find food. These adaptations are:
- Sharp ears and a composite, solid build: Starting off with their keen sense of hearing, arctic foxes are great listeners, and with directional (pointed) ears, they can hear their prey, most often the lemmings hiding out in the snow tunnels. They follow their prey’s movement through their sharp hearing and pounce on them when they can. Apart from this physiological adaptation, an arctic fox has a short and stout physique characterized by short legs, ears, a small muzzle, and a generally round body. This adaptation helps them avoid excess loss of heat during the winters since a low surface area to volume ratio traps the energy inside, therefore preventing loss of heat from the body.
- A thick multilayered fur: Arctic foxes have a thick fur that has multiple layers, unlike the red foxes, in order to survive the snow and the extreme weather conditions. The fur being dense provides adequate fiction to produce heat and keep the arctic foxes warm. The pelage acting as a cover has an oily hair guard, thus keeping the freezing moisture away from the body while the underfur insulates the animal.
- Fur on the underside of footpads: The arctic fox has to travel in the snow to forage for food, sometimes dig into the snow to find a lemming or two. Thus, to protect their feet from blisters and extreme cold, arctic foxes have fur on the underside of their footpads that acts as an insulator, keeping their feet warm and safe. It also adds up on the bright side that it makes digging up the snow easier without hurting the canid’s feet.
- Keeping up with the prey’s Reproductive Rate: The general diet of an arctic fox mostly comprises lemmings. Although they breed in numbers in optimal conditions, they are usually short-lived. Therefore, arctic foxes, in order to gain the upper hand on the prey and feed on them while they are still in the flesh, keep up with the lemming’s reproductive rate and breed between 5-9 offspring. The number can go as high as 25, which is the highest for any carnivore.
- Reduced Metabolic Rate: Arctic foxes may have a thick coat to help protect them against the cold, but it is certainly not enough to tolerate the extreme climatic conditions of the Northern Hemisphere. This is why arctic foxes conserve fat in their body. How so? By reducing their metabolic rate, which means the rate at which the food is absorbed by their body and used up as energy. This helps release less energy and accumulate fat that acts as an insulator layer.
- Color Morphs: The fascinating adaptation arctic foxes have is the changing of coats with the change in seasons. Arctic foxes, if you ever googled them, you’ll see, have two distinct color coats that are completely contrary to each other. The changing of coats is primarily for two reasons: avoiding predators and camouflaging and catching prey. Hence, during the winters, these animals have a completely white coat to blend in with their natural landscape, the snow, both to catch prey and evade predators. The white coat is also highly dense and insulating to protect against the cold. During the summer, arctic foxes have a bluish brown with tints of grey color morph that is comparatively thinner than the white coat and helps them find food in the wild when the snow is gone.
Sources
- Arctic Fox, Oceanwide
- Arctic Fox, National Geographic
