# Arctic Fox — Facts, Threats & Conservation

*Vulpes lagopus (Linnaeus, 1758) — family Canidae*

> The Arctic fox (Vulpes lagopus) has the warmest coat of any mammal, does not begin shivering until around −40°C, and changes from a brown-grey summer coat to thick white winter fur; its main modern threat is the red fox expanding north.

**IUCN status:** Least Concern globally; the Scandinavian population remains critically small  ·  **WARN range:** Arctic tundra of Eurasia, North America, Greenland, Iceland and Svalbard, Sea ice in winter

## Quick facts
| Fact | Value |
| --- | --- |
| Weight | 3–3.5 kg |
| Cold tolerance | No shivering above about −40 °C |
| Coat | Seasonal white/brown, or year-round 'blue' morph |
| Litter size | Up to 14 in peak lemming years |
| Range | Circumpolar Arctic tundra and sea ice |
| Key threat | Northward expansion of the red fox |

## Scientific classification
- **Kingdom:** Animalia
- **Phylum:** Chordata
- **Class:** Mammalia
- **Order:** Carnivora
- **Family:** Canidae
- **Genus:** Vulpes
- **Species:** Vulpes lagopus

## Conservation status
- **Status:** Least Concern
- **Population:** Several hundred thousand circumpolar
- **Trend:** Stable globally; Scandinavian population critically small
- **Assessed:** 2014
- **CITES:** Not listed
- The global listing masks a severe regional situation in Fennoscandia, where the population survives only with active red fox control and supplementary feeding.

## Key facts: Arctic Fox
- The Arctic fox has the warmest coat of any mammal and tolerates −40°C before shivering.
- Body shape minimises heat loss — the exact inverse of the fennec fox's design.
- Most change from brown-grey summer coats to white winter coats; 'blue' morphs stay dark.
- Litter size tracks lemming abundance and can reach 14 pups in a peak year.
- They travel enormous distances over sea ice, including crossings of over 1,000 km.
- Red foxes moving north with warming are outcompeting and killing Arctic foxes.

## Engineered against heat loss
Every proportion works against losing warmth: small rounded ears, a short muzzle, short legs, a compact trunk and a thick tail used as a wrap when curled up. Fur covers the footpads — the species name *lagopus* means 'hare-foot' — insulating against ice and improving grip.

A countercurrent heat exchanger in the legs keeps the paws close to freezing while the core stays warm, so heat is not wasted at the extremities. The result is an animal that maintains core temperature through Arctic winters with no shelter beyond a snow hollow.

## Two colour morphs
The white morph turns brown-grey in summer and thick white in winter, matching snow cover. The blue morph keeps a dark charcoal or brown coat year-round and is commoner in coastal and island populations — Iceland's foxes are predominantly blue — where snow cover is patchy and a white coat would be conspicuous.

The morphs interbreed freely; colour is determined by a single genetic locus rather than by separate populations.

## Lemmings, and travelling for food
Inland Arctic foxes depend heavily on lemmings, and litter size tracks the lemming cycle sharply — up to 14 pups in a peak year, few or none in a crash. Coastal foxes rely more on seabirds, eggs and carrion and are less volatile.

Winter forces long movements. Arctic foxes follow polar bears to scavenge kills and range across sea ice; tracked individuals have covered well over a thousand kilometres, including crossings between continents. That mobility depends on sea ice being there.

## The red fox problem
The clearest modern threat is competition. As the Arctic warms and shrub tundra advances north, red foxes — larger, more aggressive and better suited to milder conditions — expand into Arctic fox range. Red foxes take over dens, outcompete for food and kill Arctic foxes directly.

The Scandinavian Arctic fox population remains critically small despite decades of protection, and red fox control alongside supplementary feeding has been necessary to keep it viable. Globally the species is Least Concern because the circumpolar population is large; that number conceals a real and worsening squeeze at the southern edge of the range.

## What WARN does
WARN publishes free, sourced species education including the pressures that are hard to see. The Arctic fox is not declining because of hunting or trade — it is losing ground to another fox that warming has let move north, which is what climate-driven biodiversity loss usually looks like in practice.

If this guide helps you understand wildlife and the pressures it faces, a gift to WARN supports habitat protection and free public education in our partner countries.

## Frequently asked questions: Arctic Fox
### How cold can an Arctic fox survive?
It has the warmest coat measured in any mammal and does not begin to shiver until around −40°C. Short ears and muzzle, compact body, fur-covered footpads and a countercurrent heat exchanger in the legs all reduce heat loss.

### Why are red foxes a threat to Arctic foxes?
Warming allows shrub tundra and red foxes to advance north into Arctic fox range. Red foxes are larger and more aggressive, take over dens, outcompete for food and kill Arctic foxes directly, squeezing them at the southern edge of their range.

### Where do Arctic foxes live?
Arctic foxes inhabit circumpolar Arctic tundra and sea ice across Eurasia, North America, Greenland, Iceland and Svalbard. In winter they follow polar bears to scavenge kills and have been tracked crossing more than 1,000 km over sea ice — mobility that depends on ice being present.

### Are Arctic foxes dangerous?
Arctic foxes are not a threat to people. They are small carnivores weighing 3–3.5 kg, built for extreme cold rather than aggression toward humans. Their main modern threat is the red fox expanding north with warming, outcompeting and killing Arctic foxes at the southern edge of their range.

### How long do Arctic foxes live?
No reliable maximum lifespan figure is established for Arctic foxes. Litter size tracks lemming abundance sharply — up to 14 pups in a peak lemming year, few or none in a crash — reflecting a life history tied to Arctic food cycles rather than steady annual breeding.

### How big is an Arctic fox?
Arctic foxes weigh 3–3.5 kg according to this guide's quickFacts. They have the warmest coat measured in any mammal and do not begin shivering until around −40°C, with short ears, a compact body and fur-covered footpads that minimise heat loss.

### What do Arctic foxes eat?
Inland foxes depend heavily on lemmings, with litter size tracking the lemming cycle. Coastal foxes rely more on seabirds, eggs, fish and carrion, including scavenging from polar bear kills.

## Sources
- [IUCN Red List — Vulpes lagopus](https://www.iucnredlist.org/species/899/57549321)
- [IUCN Red List](https://www.iucnredlist.org/)

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Full guide: https://worldanimalrescuenetwork.org/wildlife-guides/arctic-fox