RUST-COLORED BEARDED ( ERIGNATHUS BARBATUS ) AND RINGED ( PHOCA HISPIDA ) SEALS FROM SVALBARD, NORWAY

Bearded and ringed seals from Svalbard, Norway, often have strongly rust-colored faces; the fore-flippers also are rust-colored in some animals. Element analyses of fur from normally colored and rust-colored seals of both species showed that high concentrations of iron were present in the colored fur, indicating that iron oxides are probably the main reason for the unnatural coloration. High concentrations of vanadium and manganese also were found in samples of colored fur. Oxides of these elements also may contribute to the discoloration. We suggest that seals acquire elements responsible for the coloration while feeding in soft-bottom sediments. Their faces and flippers make contact with rich deposits of iron monosulfide in a reducing environment. When this sediment is brought up into the water column by the seals, the iron monosulfide is oxidized to form iron oxides that precipitate onto the hair shafts of the seals. The higher incidence of rust-colored bearded seals, compared with ringed seals, is explained by the greater dependence of the former species on benthic prey items.