SEARCH

SEARCH BY CITATION

Keywords:

  • phocid seals;
  • harp seal;
  • Pagophilus groenlandicus;
  • hooded seal;
  • Cystophora cristata;
  • thermal resistance;
  • insulation;
  • fur;
  • skin;
  • blubber

Abstract

In phocid seals, blubber serves as the main thermal insulation instead of fur. The thermal function of fur, at least in adult phocid seals, has therefore been questioned. We measured the relative contribution of fur to the combined thermal resistance (insulation) offered by blubber, skin, and fur in newborn and adult harp (Pagophilus groenlandicus) and hooded (Cystophora cristata) seals, in air and water, to elucidate the role of fur as insulation in phocid seals. In air the fur contributed 90% of the combined thermal resistance of blubber, skin, and fur in newborn harp seal pups and 29% in adulrs, whereas in hooded seals the fur contributed 73% in newborn pups and 34% in adults. When submerged the thermal resistance of the fur was reduced by 84%-92%, and contributed 65% to the total insulation in newborn harp seal pups and 3% in adults, and 26% in newborn hooded seal pups and 5% in adults. We conclude that in air the fur of phocid seals makes an important contribution to the insulation of pups, and also contributes considerably to the insulation of adult animals. In water, even though the thermal resistance of the fur is dramatically reduced, the fur still contributes substantially to the insulation of pups, but its contribution in adults is negligible.