Arctic foxes quick facts
- Arctic foxes can survive temperatures colder than -46 °C.
- Their colour change is triggered by the length of daylight.
- Some Arctic fox dens have been used for about 300 years.
- Arctic foxes can have litters of up to 15 pups, and rarely more.
- One Arctic fox walked 3,506 km in 76 days.
What is an Arctic fox?
The Arctic fox is a small, fluffy fox that lives in the coldest places on Earth. Hinterland Who’s Who, a Canadian wildlife guide, says it is about the size of a large house cat.
Arctic foxes are famous for changing colour with the seasons. Many are snowy white in winter and brown or grey in summer, which helps them blend in all year round.
They are tough survivors. The Alaska Department of Fish and Game says Arctic foxes can survive temperatures colder than -46 °C (-50 °F).
| Arctic fox at a glance | |
|---|---|
| Where | treeless Arctic tundra around the North Pole |
| Weight | about 2.5 to 9 kg |
| Length | about 75 to 115 cm, including the tail |
| Coldest survived | below about -46 °C (-50 °F) |
| Food | lemmings, voles, birds, eggs, fish and leftovers |
| Pups per litter | about 7 on average in Alaska |
| Status | Least Concern |
How big is an Arctic fox?
Hinterland Who’s Who says an adult Arctic fox weighs about 2.5 to 9 kg and measures 75 to 115 cm long, including its tail. The tail makes up about a third of its length.
In Alaska, the Alaska Department of Fish and Game says adults average about 109 cm long, including a tail of about 38 cm.
Arctic foxes are small compared with the red fox, which is a close relative. Their small, round shape is one of their secrets for staying warm.
Where do Arctic foxes live?
Animal Diversity Web says Arctic foxes live on the treeless tundra all around the Arctic: in northern Europe and Asia, North America, Greenland and Iceland.
They often live near the coast, on tundra and in mountains. In Canada, Hinterland Who’s Who says they range from Ellesmere Island, in the far north, down to James Bay.
In Alaska, the Alaska Department of Fish and Game says they live along treeless coasts from the Aleutian Islands north to Point Barrow. Some Arctic foxes even travel far out onto the sea ice of the Arctic Ocean.
White foxes and blue foxes
There are two colour types of Arctic fox. The Alaska Department of Fish and Game and Hinterland Who’s Who say “white” foxes are snowy white in winter and grey-brown in summer.
“Blue” foxes are pale bluish-grey in winter and darker in summer. Hinterland Who’s Who says blue foxes are rare in Canada, but make up about half of the foxes in Greenland.
Arctic foxes change their coats twice a year. The Alaska Department of Fish and Game says they start shedding their winter fur in early April, wear their summer coat by late June, and have a full white coat again by November.
The colour change is not caused by the cold. The Alaska Department of Fish and Game says it is triggered by the length of daylight.
Built for the cold
Everything about an Arctic fox helps it keep warm. The Alaska Department of Fish and Game says its winter coat is twice as thick and dense as its summer coat.
Its body shape helps too. The Alaska Department of Fish and Game says a round, compact body, short legs and short, rounded ears and snout all help it lose less heat.
Compare that with the fennec fox of the desert, whose huge ears help it lose heat to stay cool.
Even the bottoms of an Arctic fox’s paws are furry. The Alaska Department of Fish and Game says its scientific name, lagopus, means “hare-foot” in Greek, after the furry feet of the snowshoe hare.
When it sleeps in the cold, the fox wraps its fluffy tail around its body and face, like a warm blanket.
What do Arctic foxes eat?
Arctic foxes eat almost any animal, alive or dead. Animal Diversity Web and the Alaska Department of Fish and Game say they eat lemmings, voles, insects, fish, seabirds such as puffins, eggs, dead seals and berries.
Lemmings are a favourite. Hinterland Who’s Who says a litter of pups needs about 30 lemmings a day at first, rising to more than 100 a day as they grow. A fox family can eat 3,500 to 4,000 lemmings while the pups are in the den.
Lemming numbers rise and crash every three to four years. Hinterland Who’s Who says Arctic fox families rise and fall with them.
Following polar bears
In winter, when food is hard to find, many Arctic foxes head out onto the sea ice. Hinterland Who’s Who and the Alaska Department of Fish and Game say they follow polar bears and eat the leftovers of seals the bears have killed.
It is a clever trick. The bear does the hard work of hunting, and the fox cleans up what it leaves behind.
Saving food for later
When there is plenty of food in summer, Arctic foxes save some for later. Animal Diversity Web and Hinterland Who’s Who say they store the extra food under stones, among boulders and in their dens.
Storing food like this is called caching. In the freezing Arctic, the cold keeps the food fresh, a bit like a natural freezer.
Dens used for centuries
Arctic foxes live in underground dens. Animal Diversity Web says a den is a tunnel system with many entrances, often four to eight. Hinterland Who’s Who says up to 100 entrances have been recorded.
Some dens are very old. Animal Diversity Web and Hinterland Who’s Who say some have been used for up to about 300 years, by generation after generation of foxes.
The Alaska Department of Fish and Game says burrows reach about 1.8 to 3.7 m (6 to 12 feet) underground. Foxes often dig out and enlarge old ground squirrel burrows.
Arctic fox pups
Arctic foxes usually stay with the same mate for life, Animal Diversity Web says. The Alaska Department of Fish and Game says the mother is pregnant for about 52 days.
Arctic foxes can have very large litters. The Alaska Department of Fish and Game says there are about seven pups on average in Alaska, and up to 15. Hinterland Who’s Who says litters of up to 22 have been recorded in Russia.
A newborn pup weighs only about 57 g. Hinterland Who’s Who and the Alaska Department of Fish and Game say pups first come out of the den at about three weeks, and leave home about 14 to 15 weeks after birth.
The Alaska Department of Fish and Game says young foxes are old enough to have pups of their own at about 9 to 10 months. In human care, Arctic foxes live about 16 years.
A record-breaking journey
Arctic foxes can travel incredible distances. In 2018, scientists from Norway tracked a young female fox with a satellite collar.
The scientists reported in the journal Polar Research that she walked from the Svalbard islands in Norway, across sea ice and Greenland, all the way to Canada. She covered 3,506 km in 76 days.
On one day, she travelled 155 km across the Greenland ice sheet. That is the fastest movement ever recorded for an Arctic fox. She was a blue fox from a coast where foxes eat food from the sea, and she settled in Canada, where foxes live mainly on lemmings.
Dangers for Arctic foxes
Arctic foxes have enemies. Hinterland Who’s Who says wolves eat Arctic foxes if they can catch one, and golden eagles can take young pups.
Red foxes compete with Arctic foxes for food and dens. Animal Diversity Web and Hinterland Who’s Who say red foxes have pushed Arctic foxes out of parts of northern Scandinavia.
Diseases such as rabies and mange can kill many Arctic foxes, and people have trapped them for their fur for a long time. Worldwide, the IUCN Red List lists the Arctic fox as Least Concern.
Hunting lemmings
Lemmings are small, round rodents that live in the tundra grass and under the snow. Their numbers change hugely. Hinterland Who’s Who says that in North America, lemming numbers can rise or fall ten or even twenty times over from one year to the next.
When lemmings are plentiful, an Arctic fox does not need to travel far to eat. Hinterland Who’s Who says it may hunt over an area of just 2.5 to 5 square kilometres.
When lemming numbers crash, Arctic fox numbers fall with them, because there is much less food for the pups.
Arctic foxes and people
People have trapped Arctic foxes for their thick fur for a long time. Animal Diversity Web says that on Alaska’s Pribilof Islands, Arctic foxes have been farmed for fur since 1865.
Fur farmers also put foxes on Alaskan islands where they had never lived. The Alaska Department of Fish and Game says these foxes are now being removed, because they do not belong there and harm the island wildlife.
Arctic foxes can wander across borders too. The Alaska Department of Fish and Game says one fox tagged in Russia was later caught near Wainwright, Alaska.
Three things people get wrong
Arctic foxes do not turn white because of the cold. The length of daylight triggers the change.
Not all Arctic foxes are white. Blue foxes are bluish-grey, even in winter.
Arctic foxes are not bigger than red foxes. They are small, about the size of a large cat.
Did you know? The Arctic fox’s scientific name, lagopus, means hare-foot, because even the bottoms of its paws are furry.
Try it
Draw an Arctic fox in its white winter coat and its brown summer coat. Where would each one blend in best?
Knowledge check
What makes an Arctic fox change colour?
Show answer
The length of daylight.
Why do Arctic foxes follow polar bears?
Show answer
To eat the leftovers of seals the bears have killed.
Frequently asked questions
Where do Arctic foxes live?
Arctic foxes live on the treeless tundra all around the Arctic, in northern Europe and Asia, North America, Greenland and Iceland.
Why do Arctic foxes change colour?
Many Arctic foxes are white in winter and brown in summer to blend in. The change is triggered by the length of daylight.
How do Arctic foxes stay warm?
They have a very thick winter coat, furry paws, a compact body and short ears, and they wrap their fluffy tail around them to sleep.
What do Arctic foxes eat?
They eat lemmings, voles, insects, fish, seabirds, eggs, dead seals and berries, and in winter they eat polar bears’ leftovers.
How many pups do Arctic foxes have?
Arctic foxes can have very large litters, about seven on average in Alaska and up to 15. Litters of up to 22 have been recorded.
Are Arctic foxes endangered?
Worldwide, Arctic foxes are listed as Least Concern, but red foxes, disease and trapping cause problems in some places.
Sources
- Animal Diversity Web, University of Michigan: Arctic fox — range, colours, paws, dens, pairs, diet, caching, red foxes and status
- Alaska Department of Fish and Game: Arctic fox — size, Alaska range, colour phases, moult, pups, den depth and diet
- Alaska Department of Fish and Game: foxes wear new coats for spring — cold tolerance, coat thickness, what triggers the moult, body shape and furry paws
- Hinterland Who’s Who: Arctic fox — size, Canadian range, blue foxes, lemmings, dens, polar bears, predators and disease
- Polar Research: an Arctic fox’s journey from Svalbard to Canada — the record 3,506 km journey
