With the disappearance of the wolf, lynx and bear, the fox has become the largest predator in the National Park.

Like the stone marten the fox is widely distributed in the National Park and well adapted. It feeds largely on ungulate carcasses, worms, mice and marmots. Although the fox is protected just like all other animals and plants in the Park, and its population allowed to develop freely, none of its prey have become extinct.

The mating season occurs between December and February. The gestation period is 60 to 63 days and the young foxes are born in March or April, 4 to 6 cubs in a litter. They only leave the den after 4 to 7 weeks.