Polar bears are the ultimate survivors of the Arctic, thriving in temperatures as low as -40 degrees Celsius and frequently diving into the freezing waters of the Arctic Ocean. Despite getting wet—even when emerging from icy water—they don’t freeze, raising questions with scientists for decades. Now, new research has uncovered the secret behind why polar bears don’t freeze.
Discover Wildlife reports that the latest search for this answer began when Professor Bodil Holst of the University of Bergen noticed something strange while watching a TV show. Infrared cameras, which detect heat, couldn’t see polar bears, suggesting that their fur was extremely cold.
This raised a fascinating question with the professor: If polar bears’ fur stays cold, why don’t they freeze? And so, PhD student Julian Carolan of Trinity College Dublin set off with a research team to figure out just why polar bears can survive so readily in the icy environment of the Arctic.
According to the group’s findings, which have been published in Science Advances, the key lies in polar bear’s sebum—a natural skin oil secreted from glands beneath their fur. This oily coating contains a mixture of cholesterol, diacylglycerols, and fatty acids, all of which are water-repellent and help prevent the formation of ice.
This natural oil ensures that water slides off their fur quickly, stopping it from freezing on their bodies. This, the researchers argue, is crucial for the polar bear’s survival, as frozen fur would trap cold and reduce insulation, making it harder for the bears to stay warm.
Beyond keeping them dry, this natural oil on their fur provides another advantage: stealth. Polar bears rely quite a lot on seals as one of their primary sources of food. As such, they need to stalk these creatures without being detected. But have you ever seen an animal as big as a polar bear try to sneak?
Luckily, with the natural oil their body secretes, the polar bears are not only able to withstand freezing, but they are also able to slide quietly over the ice so that they can stalk seals without being noticed. And it seems that the indigenous Arctic communities have long recognized the unique properties of polar bear fur.
The researchers found several historical accounts of hunters using polar bear fur on hunting gear, allowing them to slide silently over the ice. However, one lingering question is whether the polar bear’s diet influences the composition of the sebum they excrete, as they consume a fat-rich diet, primarily from seals, which may contribute to the special makeup of their oily fur.
Scientists are now investigating whether other bear species, like brown bears, have similar properties in their fur. If nothing else, those hybrid polar bear and brown bear babies may adopt some of these traits.
