 Although they ranged far south during the Wisconsinan, the onset of warm conditions shrank their range toward the north, and have only recently reclaimed their former American ranges because of human-induced environmental changes.Genetic testing indicates two distinct red fox refugia exist in North America, which have been separated since the Wisconsinan.The northern (or boreal) refugium occurs in Alaska and western Canada, and consists of the large subspecies "V. v. alascensis", "V. v. abietorum", "V. v. regalis", and "V. v. rubricosa".