According to a recent study published in Science Advances, a greasy hair day keeps the ice away — for polar bears, that is.
After examining polar bear fur, an international research team identified what helped keep polar bears ice-free, even in sub-zero temperatures. It all comes down to their greasy fur.
“This work not only represents the first study of the composition of polar bear fur sebum, but it also resolves the question of why polar bears don’t suffer from ice accumulation,” said Richard Hobbs, an assistant professor and Royal Society-Science Foundation Ireland University Research Fellow in Trinity’s School of Chemistry and the AMBER Research Ireland Centre, and senior author of the study, in a press release.
Greasy-Haired Polar Bears
Polar bear fur is a marvel. It’s double-insulated to help keep the bears warm in the arctic conditions, and the hair itself is hollow. While polar bears have black skin, their fur is actually translucent, which makes the fur appear white to humans. Along with all of these fascinating features, it also prevents ice from sticking to it. This ability has stumped researchers in the past, but they now know that it has to do with the sebum on the bear's fur.
Sebum is the main ingredient in the oil that the body naturally produces to help keep skin moisturized. It’s made up of cholesterol, triglycerides, and fatty acids. An excessive amount can build up on the body, leading to acne. It can also build up in hair — which gives it that greasy, dirty look.
On polar bears, their sebum is made up of diacylglycerols, cholesterol, and fatty acids, which prevent ice from sticking to their fur.
With these findings, researchers have a better understanding of polar bear biology, and could also use this information to make more adaptive cold weather gear, such as skiing or snowboarding equipment.
Read More: How Did Animals Get Their Spots and Stripes?
Studying Polar Bear Sebum
Researchers collected hair samples from six polar bears and did a series of different tests on them. From the results, the team pinpointed the sebum as what was preventing ice from adhering to the polar bear fur.
“We measured ice adhesion strength, which is a useful measure of how well ice sticks to fur,” said Julian Carolan, Ph.D. candidate from Trinity College Dublin’s School of Chemistry and the AMBER Research Ireland Centre and lead author of the study, in a press release.
“The sebum quickly jumped out as being the key component giving this anti-icing effect as we discovered the adhesion strength was greatly impacted when the hair was washed. Unwashed, greasy hair made it much harder for ice to stick,” he added, in the press release.
Why Polar Bear Sebum Is Different
Polar bears are far from the only animals to have sebum in their fur. But why is it that ice will stick to greasy human hair and other animal fur and not a polar bear’s? After identifying that sebum had anti-ice properties, researchers did a deeper analysis of the oil.
It turns out that while most sebum is made of cholesterol, diacylglycerols, and fatty acids, including a polar bear’s, they were missing one component — squalene, an active part of sebum found on humans and other aquatic mammals, such as otters.
“Despite having thick layers of insulating blubber and fur and spending extensive periods in water at sub-zero temperatures, it seems that the fur grease provides a natural route for polar bears to easily shed ice when it forms due to the low ice adhesion on their fur,” said Hobbs in the release.
These findings could lead to new and safe ways of creating an anti-stick coating on certain products.
“We expect that these natural lipid coatings produced by the bear will help us to develop new more sustainable anti-icing coatings that may replace problematic ‘forever chemicals’ like PFAS that have been used as anti-icing coatings,” Hobbs concluded in a press release.
Read More: 5 Things You Never Knew About Polar Bears
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Science Advances. Anti-icing properties of polar bear fur
Library of Congress. Is a polar bear’s fur transparent?
Health Line. What Is Sebum and Why Does It Build Up on Skin and Hair?
A graduate of UW-Whitewater, Monica Cull wrote for several organizations, including one that focused on bees and the natural world, before coming to Discover Magazine. Her current work also appears on her travel blog and Common State Magazine. Her love of science came from watching PBS shows as a kid with her mom and spending too much time binging Doctor Who.
