Anti-icing properties of polar bear fur

The polar bear (Ursus maritimus) is the only Arctic land mammal that dives into water to hunt. Despite thermal
insulation provided by blubber and fur layers and low Arctic temperatures, their fur is typically observed to be free
of ice. This study investigates the anti-icing
properties of polar bear fur. Here, we show that polar bear fur exhibits
low ice adhesion strengths comparable to fluorocarbon-coated
fibers, with the low ice adhesion a consequence of
the fur sebum (hair grease). Lipid analyses reveal the presence of cholesterol, diacylglycerols, anteisomethyl-branched
fatty acids, and the unexpected absence of squalene. Quantum chemical calculations predict low ice
adsorption energies for identified lipids and high adsorption for squalene, suggesting that sebum composition is
responsible for the observed anti-icing
properties. Our work enhances understanding of polar bears and their interactions
with their environment and builds on Inuit knowledge of natural anti-icing
materials.