Red foxes (Vulpes vulpes) at their expanding front in the Canadian Arctic have indigenous maternal ancestry

The red fox (Vulpes vulpes) expanded its distribution over large parts of the Canadian Arctic during the twentieth century and is now considered a threat to the arctic fox (Vulpes lagopus). Some authors have proposed that the European red fox, introduced in Eastern North America during the eighteenth century, may have spread and caused the species’ expansion in the Arctic. Assessing the biological origin of red foxes in the Nearctic is critical to determine whether their presence constitutes a case of an invading exotic species. We analyzed genetic material obtained from four red foxes at Herschel Island (Yukon) and Bylot Island (Nunavut), at the northern expanding front of the species. Samples from Bylot provide the northernmost genetic information on red fox obtained worldwide. We identified mitochondrial DNA haplotypes in red foxes from both Arctic locations that were phylogenetically divergent from those in Eurasia, but shared with neighboring indigenous North American populations. Thus, our results indicate that the twentieth century expansion of red foxes in the Canadian Arctic involved nearby populations potentially benefiting from habitat changes, rather than an exotic species invading new habitats.