An international team of scientists has uncovered a remarkable secret behind the survival of polar bears in one of the harshest climates on Earth: their greasy fur. This new insight reveals how the composition of polar bear hair plays a critical role in helping them withstand the freezing conditions of the Arctic, shedding ice with remarkable efficiency. But the implications of this discovery extend far beyond polar bear biology, with potential applications in everything from anti-icing coatings to innovative products for winter sports.
The Polar Bear’s Anti-Icing Secret: Greasy Fur
At the heart of the breakthrough lies an unexpected substance found in polar bear fur: sebum, the greasy secretion produced by hair follicles. Sebum is made up of a blend of lipids, including cholesterol, diacylglycerols, and fatty acids. These components combine to create a surface that resists ice buildup, ensuring the polar bear’s fur remains free from ice, even in the harshest conditions.
This discovery came after an extensive study involving polar bear fur samples collected from six bears in the wild. The researchers focused on the sebum as the key factor in the polar bear’s ability to keep its fur ice-free, even when exposed to sub-zero temperatures and icy water. When they analyzed the ice adhesion strength, hydrophobicity (water-repelling ability), and freezing delay time, they found that the greasy fur significantly slowed ice formation compared to clean, washed fur.
Julian Carolan, a Ph.D. candidate at Trinity College Dublin’s School of Chemistry and the AMBER Research Ireland Centre, led the study, which was published as a cover story in Science Advances. Carolan explained, “We measured ice adhesion strength, which is a useful measure of how well ice sticks to fur; hydrophobicity, which dictates whether water can be shed before it freezes; and freezing delay time, which simply shows how long it takes for a drop of water to freeze at certain temperatures on a given surface. We then compared the performance of the polar bear hair with that of human hair and two types of specialist human-made ‘ski skins.'”
The results were eye-opening: polar bear fur, when unwashed and coated with sebum, significantly outperformed other types of fur, including human hair, in preventing ice buildup. When the hair was washed and the sebum removed, its performance declined, behaving much like human hair, to which ice readily adheres.
The Role of Sebum in Ice Prevention
The sebum in polar bear fur forms a natural protective barrier against the ice. It’s an oily coating that reduces the adhesion of water and ice, allowing the polar bear to remain agile and insulated even in freezing temperatures. The chemical analysis of the sebum revealed that it was composed of specific lipids like cholesterol, diacylglycerols, and fatty acids—components that contribute to its slippery, water-repelling qualities. Interestingly, squalene, a fatty metabolite found in human hair and in the fur of aquatic animals like sea otters, was notably absent from polar bear fur. This absence is significant from an anti-icing perspective, as the presence of squalene in other animals is typically associated with water repellency but might not be as effective at preventing ice adhesion.
This revelation about the composition of polar bear sebum opens up new possibilities for creating advanced anti-icing materials. According to Dr. Richard Hobbs, an assistant professor and senior author of the study, “Animals living in polar habitats have emerged as a source of inspiration for the development of new anti-icing materials. Our work shows that polar bear fur provides an alternative strategy to produce an anti-icing surface based on the characteristic blend of lipids present in their fur sebum or hair grease.”
Hobbs and his team hope that this discovery can lead to more sustainable alternatives to harmful chemicals currently used for anti-icing purposes. For example, substances like PFAS (per- and polyfluoroalkyl substances), often used in anti-icing coatings, are highly persistent in the environment and can be toxic. The idea is to create new, environmentally friendly coatings that mimic the properties of polar bear sebum, which would not only be effective but also less harmful to the planet.
Applications Beyond Polar Bear Biology
The potential applications of this discovery extend far beyond just understanding polar bears and their ecology. One of the most exciting areas of research is the use of artificially synthesized sebum as an anti-icing surface coating. Scientists are investigating how to replicate the properties of polar bear fur in materials that can be used in industries ranging from transportation to winter sports. A similar concoction of sebum could be used to create better anti-icing coatings for airplanes, cars, and roads, helping to reduce the buildup of ice and snow in extreme weather conditions.
In addition to anti-icing technologies, researchers are exploring how polar bear-inspired coatings could improve the performance of ski skins—the specialized equipment used by skiers and snowboarders to climb hills or traverse icy terrain. Just as polar bear fur resists ice buildup, ski skins coated with a similar sebum-based material could potentially make it easier for athletes to glide over icy surfaces without the added drag or friction caused by snow accumulation.
The Polar Bear’s Hunting Strategies and Inuit Techniques
Beyond the practical applications for anti-icing technology, this research also sheds light on the fascinating hunting behaviors of polar bears and provides insights into traditional Inuit knowledge. One of the primary hunting strategies of polar bears is still hunting, where they wait motionless beside breathing holes in sea ice, lying in wait for seals to surface. The grease on their fur plays a subtle yet crucial role in helping them silently slide across the ice. The lower the ice adhesion, the quieter and faster they can move—essential for sneaking up on prey without making noise that would alert seals.
The Inuit have long understood the importance of minimizing noise when hunting on ice, and this knowledge is reflected in their traditional hunting techniques. According to Prof. Bodil Holst from the University of Bergen, “Our findings also help us understand the subtlety of the steps taken by Inuit people to optimize hunting strategies to mimic the polar bear method of still hunting. Inuit hunting stools are sometimes shod with polar bear fur on the feet to avoid noise when moving on the ice, while people also sometimes wear ‘polar bear trousers,’ ensuring the entire contact area with the ice is covered in low ice-adhesion polar bear fur for optimal noise reduction.”
This traditional use of polar bear fur by the Inuit demonstrates how they have adapted their techniques to mimic the efficiency of the polar bear in the wild. Remarkably, the traditional Inuit practice of preserving the sebum on polar bear pelts aligns closely with the scientific findings of this study. By ensuring the fur is not washed and the sebum remains intact, the Inuit optimize the fur’s natural anti-icing and noise-reducing properties. This careful preservation of the grease on the fur is crucial to the effectiveness of their hunting techniques, as it reduces friction and ensures a quieter, smoother glide over the ice.
Looking Ahead: The Future of Anti-Icing Technologies
The discovery of polar bear fur’s anti-icing capabilities offers new hope for creating sustainable alternatives to synthetic anti-icing chemicals. The team’s findings suggest that the key to reducing ice adhesion lies in the natural combination of lipids found in polar bear sebum, which could be replicated in artificial materials for a variety of uses. This research not only deepens our understanding of polar bear biology and Inuit hunting techniques but also opens the door for a new era of anti-icing technologies that are both environmentally friendly and highly effective.
As scientists continue to explore the potential of polar bear-inspired materials, we may see the development of cutting-edge products that help reduce ice buildup in everyday applications, from transportation to winter sports. Whether it’s preventing dangerous ice accumulation on roads, improving the performance of winter sports gear, or reducing environmental harm caused by traditional anti-icing chemicals, the greasy secret of polar bear fur could have wide-ranging effects on both our technological advancements and our understanding of nature’s ingenuity.
In summary, the study of polar bear fur and its anti-icing properties is a powerful reminder of the extraordinary ways animals have adapted to survive in extreme environments. By unlocking the secrets of polar bear sebum, researchers are not only solving an important ecological puzzle but also paving the way for more sustainable and innovative solutions in a variety of fields.
Reference: Science Advances (2025). DOI: 10.1126/sciadv.ads7321