National Geographic : 2004 Oct
A B LU E ARCT I C FOX chases a white arctic fox during early spring in Svalbard (opposite top). Most arctic foxes turn white in winter, but some have brownish blue fur (mid dle). Many blue foxes live in coastal areas, where they blend into dark backgrounds. Both color types live in Svalbard, where competition for mates rouses rivals in March. One sleeping male awakens and snarls when confronted by a challenger (opposite bottom). On a frigid morning another napping fox's steaming breath rises (below). Some parts of the arctic foxes' range, like Svalbard, have no lemmings, so foxes there feed on seabirds, geese, and their eggs in summer. In winter the opportunist foxes scavenge seal and reindeer carcasses. Compared with Hudson Bay, Svalbard's fox population is more stable. "But because they rely on marine species, they have high concentrations of contaminants like PCBs," says Eva Fuglei, a wildlife biolo gist at the Norwegian Polar Institute, who is studying the effect of the toxics on the foxes' disease resistance and reproduction.