Introducing the Cutest Fiber Optics in Nature

Prepare to be amazed by the wonders of fiber optics, the technology that has revolutionized our lives, from the internet to novelty desk toys. But what if I told you that nature had beaten us to it? Yes, several species possess body parts with fascinating fiber optic properties, but there is one animal that stands out as the epitome of cuteness—the polar bear.

Scientists have long debated whether polar bear fur is a natural form of fiber optics, not intended for sending WhatsApp stickers but rather for the purpose of keeping these magnificent creatures warm. Fiber optic cables are essentially tubes made of two different materials, typically a glass core surrounded by a special plastic. These cables utilize a physics principle called total internal reflection to transmit light over long distances.

Interestingly, polar bear fur bears a striking resemblance to fiber optic cables. Each individual hair of these utterly adorable yet lethal animals is a hollow tube. Although replacing glass with air significantly weakens the fiber optic effect, some light does bounce around within these tubes. The question is whether this phenomenon serves any useful purpose.

In the 1970s, researchers noticed that polar bear pelts reflected less ultraviolet light than expected. One possible explanation, suggested by another team, was that the missing UV light was being bounced along the hollow core of the bear's hairs, ultimately reaching the lower layer of fur. This layer, composed of denser and softer fur, efficiently traps the additional heat carried by sunlight and keeps it close to the bear's skin. Moreover, the bear's skin itself is almost black, which aids in maximum light and heat absorption.

Polar bears might not only utilize their fiber optic-like fur to trap heat but also to sense it. The scattering of light at different angles could create temperature variations, allowing the bear to discern the position of the Sun in the sky, even on cloudy days. However, these theories remain somewhat controversial.

Polar bear fur is excellent at scattering light, giving their pelts a white appearance and providing them with effective Arctic camouflage. This is quite the opposite of what we desire in our fiber optic technology, where we aim to direct light from one specific starting point to another. Some scientists have conducted experiments on these hollow hairs and concluded that light does not travel far enough down them to exhibit a useful fiber optic effect. They argue that the material comprising polar bear fur causes excessive loss of light, rendering it impractical for true fiber optic applications.

Nevertheless, other researchers contend that if we consider a bundle of hairs working together, their collective action could compensate for the individual hair's lossiness. In other words, the light might travel down one hair for a distance, then jump to another, continuing this pattern until it reaches the lower layer of fur. This explanation could account for how some light is directed to the skin while the rest bounces out, creating the bear's white appearance. It seems that scientists need to broaden their understanding of how fiber optics can manifest in nature.

Despite the lack of consensus on polar bears' fiber optic capabilities, some individuals have already begun leveraging the properties of their fur to develop innovative technologies. In 2023, a team from the University of Massachusetts claimed to have created a wearable, artificial version of polar bear fur using different plastics. These synthetic hollow fibers, like their natural counterparts, are only one part of the equation. The other half consists of a darker under-material that absorbs the heat from the scattered light. When exposed to direct sunlight, this artificial fiber-optic fur allegedly keeps you comfortable in temperatures up to 10 degrees Celsius cooler than if you were wearing regular cotton. Although reliance on direct sunlight is currently a limitation, the team envisions future iterations of the design that could operate efficiently under ambient indoor lighting. So, while we may never be as adorable as baby polar bears, we might soon have fashion options that keep us just as toasty.