A naked arctic fox of the blue morph
We just got great photos of arctic foxes from Johann Oli Hilmarsson, who is well known for his bird photos. One of the pictures is of a „naked fox" or an arctic fox with hypotrichosis disease, which makes the foxes loose a majority of its fur. This disease is only known in Icelandic foxes, it is not genetic but the pups get infected by their mother. Fox pups with the disease have higher mortality rate than other fox pups but it is not known to affect mortality of adult foxes. Naked foxes have higher energy demands than other foxes and thus spend more time finding food. The females with the disease have no problem finding mates and they are even more fertile than other female foxes. The males, however, rarely manage to keep a territory or a mate, possibly because they use all their energy in feeding to prevent heat loss.
Pall Hersteinsson, Gudmundur Georgsson, Stefán Adalsteinsson & Eggert Gunnarsson (2007). The naked fox: hypotrichosis in arctic foxes (Alopex lagopus
). Polar Biol (2007) 30:1047-1058