Scientists unravel the secrets of polar bear fur

In a groundbreaking development, three engineers from the University of Massachusetts Amherst have successfully created a synthetic fabric that emulates the properties of polar bear fur, concluding an 80-year-long quest to develop such a textile. 

The recent publication of their findings in the journal ACS Applied Materials and Interfaces marks a significant step forward in textile innovation, with potential applications in a variety of commercially available products.

Polar bears are known for their ability to withstand the brutally cold temperatures of the Arctic, often as low as -50 degrees Fahrenheit. These creatures have numerous adaptations that enable them to thrive in such harsh conditions, but scientists have been particularly intrigued by the role their fur plays in maintaining warmth. Since the 1940s, researchers have been investigating how polar bear fur keeps them warm and how to replicate its properties in a synthetic material.

Contrary to popular belief, insulation isn’t the only way to stay warm in freezing weather. Over the past few decades, it has been discovered that many polar animals, including polar bears, actively utilize sunlight to maintain their body temperature. Polar bear fur is a prime example of this phenomenon, as it is incredibly effective at transmitting solar radiation towards the bears’ skin.

Trisha L. Andrew is the paper’s senior author and an associate professor of Chemistry at UMass Amherst. She explains that polar bear fur serves as a natural fiber optic, conducting sunlight down to their black skin, which then absorbs the light and warms the bear. Furthermore, the fur is remarkably efficient at preventing the heat from escaping, creating a self-warming blanket that retains warmth close to the skin.

Professor Andrew and her team have developed a bilayer fabric that mimics these properties. The fabric’s top layer consists of threads designed to conduct visible light down to the lower layer, which is made of nylon and coated with a dark material called PEDOT. 

Like polar bears’ skin, PEDOT warms efficiently. As a result, a jacket made from this material is 30 percent lighter than a cotton counterpart, yet it can keep the wearer comfortable at temperatures 10 degrees Celsius colder, provided that there is sunlight or sufficient indoor lighting.

Study lead author Wesley Viola, who works at Andrew’s startup Soliyarn, LLC, explained the potential sustainability benefits of this innovative fabric.

“Space heating consumes huge amounts of energy that is mostly fossil fuel-derived,” said Viola. “While our textile really shines as outerwear on sunny days, the light-heat trapping structure works efficiently enough to imagine using existing indoor lighting to directly heat the body. By focusing energy resources on the ‘personal climate’ around the body, this approach could be far more sustainable than the status quo.”

With support from the National Science Foundation, the research is already being applied in real-world contexts. Soliyarn has initiated production of the PEDOT-coated cloth, paving the way for an array of sustainable and energy-efficient products that harness the unique properties of polar bear fur.

More about polar bears

Polar bears (Ursus maritimus) are large carnivorous mammals that inhabit the Arctic regions, primarily found in countries like Canada, Russia, Greenland, Norway, and the United States (Alaska). They are well-adapted to survive in the harsh, cold environments of the Arctic, displaying several unique characteristics and behaviors.

1. Physical adaptations: Polar bears have thick white fur that not only provides camouflage in the snowy surroundings but also helps in trapping and transmitting solar radiation to their black skin, which absorbs the heat. They have a dense layer of blubber (fat) underneath their skin, which further insulates them from the cold and serves as an energy reserve during lean hunting periods. Their large, wide paws distribute their weight on the ice, aiding in swimming and preventing them from breaking through thin ice.
2. Size: Polar bears are the largest land carnivores, with adult males weighing between 900 to 1,600 pounds (410 to 730 kilograms) and measuring 8 to 10 feet (2.4 to 3 meters) in length. Adult females are generally smaller, weighing between 330 to 650 pounds (150 to 295 kilograms) and measuring 6 to 8 feet (1.8 to 2.4 meters) in length.
3. Diet: They are primarily seal hunters, relying on their excellent sense of smell to detect seals’ breathing holes in the ice. Polar bears ambush seals by waiting patiently near the breathing holes or breaking into the seals’ dens. They also occasionally feed on fish, birds, and carrion, but seals make up the majority of their diet.
4. Reproduction: Polar bears have a relatively slow reproductive rate. Mating occurs between April and June, and pregnant females prepare maternity dens in the snow during the fall. They give birth to one or two cubs between November and January, and the cubs remain with their mothers for about two and a half years, learning essential survival skills.
5. Habitat and threats: Polar bears are primarily dependent on sea ice for hunting, breeding, and denning. However, due to climate change and the resulting loss of sea ice, their habitats are shrinking, posing a significant threat to their survival. Other threats to polar bears include pollution, oil and gas development, and increased human activity in the Arctic.

Polar bears are considered a vulnerable species by the International Union for Conservation of Nature (IUCN) and are protected under various national and international laws and agreements. Conservation efforts focus on reducing greenhouse gas emissions, protecting their habitats, and minimizing human-polar bear conflicts.

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