The Arctic fox (Alopex lagopus): Adaptations, Morphology and Behaviour
The Arctic fox is a relatively small fox, with reasonably short legs and a large fluffy tail. It has a circumpolar distribution of all the Arctic tundra habitats, through North American and Eurasian Arctic tundra to the alpine tundra of Fennoscandia. The Arctic fox also inhabits most Arctic islands.
There are two distinct colour morphs in the Arctic fox population. First there is the traditionally envisioned ‘white’ morph which is virtually pure white in winter, with a few dark hairs on the tip of the tail. In summer the white moults to brown with a grey-white underside. The other colour morph is ‘blue’ with the fur in winter being brown tinged with a blue sheen which in the summer moults to a darker chocolate brown. (Angerbjörn et. al, 2004a)
The proportion of blue colour morphs increase in coastal areas and on islands, the blue morph is advantageous in these areas as they are better able to blend in to the ice free shorelines, thus enabling them to hunt more effectively. The white colour morph is naturally better suited for the inland, snow covered areas as it acts effective camouflage in a snowscape .
The fox’s winter fur is very thick and soft, with a dense underfur and long outer guard hairs. Out of all mammals the insulating properties of the fur is the best, this means that the Arctic fox has no need to increase its metabolic rate to maintain homoeothermy (Prestrud, 1991 cited in Angerbjörn et. al, 2004b).
In coastal areas the foxes have access to stable food resources such as cliffs with bird colonies and the sea shorelines. Inland foxes have greater difficulties foraging for food as these a typically area of low productivity. The exception to this occurs once every 3 to 5 years when there is a super abundance of lemmings and voles. In winter Arctic foxes in areas with a predictable abundance of food can produce a body fat content of up to 40% (Prestrud, 1992; Prestrud and...