[Lipids on the hair surface and the waterproof properties of the mammalian fur coat].

Lipid-like substances incorporated in keratinized parts of the hair or appearing on its surface as sebaceous secretion act as detergents in water. At a sufficient concentration they decrease water surface tension to 0.03 N/m, and, contrary to widespread opinion, should contribute to fur wetting. The influence of these lipids on water surface tension markedly varies among both semiaquatic and land mammals, but in any case their natural concentration is too low to significantly affect the waterproof properties of the cover of the swimming animals.