Dwindling food supply
There are several possible explanations for the decreasing numbers. An inadequate supply of small rodents, the primary source of food, is a very likely factor. Arctic foxes can also live on the remains of prey left by larger predators – wolves, lynxes and bears. But there are not many of those left, either.
Scabies
The red fox population has increased in the Swedish mountains during recent decades. It moves into the dens of Arctic foxes and may kill any young it finds there. Scientists have also observed that Arctic foxes have been infected with scabies carried by red foxes, and that some die of the illnesses that result.
