BODY INSULATION OF SOME ARCTIC AND TROPICAL MAMMALS AND BIRDS

Abstract

Insulation measurements on raw skins from 16 arctic and 16 tropical mammalian spp. are given. There is, as would be expected, a high correlation between the thickness of the fur and the insulation. The smaller arctic mammals (weasels, lemmings) have much less insulation than the larger, and overlap many of the tropical spp. Among animals from the size of a fox to the size of a moose there is no correlation between insulation and body size; all have about the same insulation per surface area. When submerged in icewater, seal blubber retains about the same insulation as in air at 0[degree]C. In the polar bear, heat transmission through the fur increases 25-50 times when submerged, because of complete wetting of the skin surface and absence of blubber. The beaver''s heat transmission increases less when submerged, as it retains an insulating layer of air in the fur next to the skin.