They are monogamous and may mate for life. Their dens are underground burrows usually in the side of a hill or cliff. They may burrow into snow during a blizzard. Several foxes may come together where the food supply is plentiful. Arctic foxes do not hibernate, are actihe ve at any hour and show little fear of man. They have lived as long a 14 years in captivity but only live about half as long in the wild. They have a high pitched yapping bark. A short bark serves as a warning note to the young.