Fox populations: Circumpolar
The northern limit of the distribution of the red fox is around the Arctic circumpolar zone. Further north, a different type of fox, the arctic fox (scientific name Alopex lagopus) lives.
Arctic and red foxes descend from a common ancestor which is now extinct. Both species are similar in physical appearance but arctic foxes are smaller than red foxes and have much thicker under-fur. At first sight, the colour of their coat is the main difference: red foxes are typically reddish (although other colour varieties exist) while arctic foxes have two colour morphs: blue and white. The white variant is brown-grey in summer and white in winter, while the blue variant is dark brown throughout the year. Arctic foxes are very well adapted to cold climates. For instance, their rounded ears and shorter muzzle help reduce heat loss.
Competition between red and arctic foxes
Arctic and red foxes are not only similar in physical appearance but also in behaviour, having similar social, territorial and breeding behaviour, and are both opportunistic predators. It is not very surprising therefore, that where they coexist, arctic and red foxes compete for resources. This competition occurs at the southern limits of the arctic fox distribution, in the tundra region, which favours red foxes. Since red foxes are larger and weigh more than arctic foxes, they dominate the smaller species where they co-exist. Further north, arctic foxes are better equipped to withstand colder climates and, in years of high food abundance, produce more young and thus out-compete red foxes.
This advantage in competition of red versus arctic foxes, added to warming climates and to hunting pressure on arctic foxes in Scandinavia, has lead to a drastic decline of the Scandinavian population of arctic foxes. Despite their protection since 1928, arctic foxes in Europe are classified as critically endangered (see the European Mammal Assessment).
Explore the menu on the left to find out more about foxes in different regions. If you want more specific information on foxes in certain regions, please click on your region of interest and you will find links to other websites.
Websites of interest
For more information on research on arctic foxes:
- Sefalo - the Scandinavian arctic fox project
- Hersteinsson, P. & Macdonald, D.W. (1982) Some comparisons between red and arctic foxes, Vulpes vulpes and Alopex lagopus, as revealed by radio tracking. Symposia of the Zoological Society of London 49, 259-289.
- Hersteinsson, P. & Macdonald, D.W. (1992) Interspecific competition and the geographical distribution of red and arctic foxes Vulpes vulpes and Alopex lagopus. Oikos 64, 505-515.