Nature has influenced many of the world's greatest inventions. The idea for Velcro fabric fasteners was sparked as its inventor was removing burdock burrs from his dog's fur after a walk. Airplanes, naturally, mimic a bird in flight. And microneedles have the mosquito to thank for a design that minimizes the pain of an injection.
Tasked with searching for a sustainable, proven solution to tricky engineering challenges, designers are increasingly allowing nature and their imaginations to take the lead. The field of biomimetics or biomimicry looks to structures and biological processes found in nature for inspiration.
"One of the common elements of humanity and throughout history and across cultures is imagination," said Robert Blasiak, a researcher at the Stockholm Resilience Center, which looks how to reconnect society with nature. "And I think biomimetics is an area where dreaming is required. It's one of the ingredients for making the whole thing work."
Streamlining trains with birds on the mind
A classic example of biomimicry is the Japanese bullet train, the Shinkansen, first introduced in 1964. Traveling at a top speed of 320 kilometers (199 miles) per hour, the high-speed train network has revolutionized mass transit in Japan and provided a cleaner alternative to private automobiles.
Earlier designs weren't as sleek and aerodynamic as today's engines, resulting in vibrations and noise during travel — especially when the train would shoot through tunnels and leave behind a sonic boom.
In 1994, engineer Eiji Nakatsu was tasked with eliminating the explosive bang, vibration and pressure waves and develop a smoother ride. An avid birdwatcher, Nakatsu made changes to the train's design based on an owl's wing and the spindle-like body shape of an Adelie penguin.
To eliminate the sonic boom, he modeled the nose of the train after the kingfisher's long, tapered beak, which allows it to dive into water to catch fish with barely a splash. The booms stopped, and as a bonus, the trains were able to travel 10% faster and use 15% less electricity.
Solar panels optimizing the sun's rays
As the world tries to move away from fossil fuels, solar photovoltaics are "becoming the lowest-cost option for new electricity generation in most of the world," according to the International Energy Agency.
To make them even more efficient, engineers took their cue from the wing of the rose butterfly, a cold-blooded insect native to Southeast Asia, which absorbs energy from the sun to stay warm. To do so, the creature has developed black wings marked with tiny holes only a millionth of a meter wide. These holes scatter light as it hits the dark surface, making it easier for the butterfly to use the sun's energy to heat up.
By incorporating similar holes in their designs, engineers have developed solar panels that are thinner and lighter. Not only that — they absorb more energy than traditional solar panels, according to the researchers.
Scientists at Princeton University were also inspired to improve solar panel efficiency by looking at leaf structures. They included microscopic folds in the panel's surface to channel light waves and increase electricity generation by nearly 50%.
"By adding these curves, we create a kind of wave guide," said biological engineering professor Yueh-Lin Loo, who was part of the research team. "And that leads to a greater chance of the light being absorbed."
Harvesting fog in the desert
Another insect that has influenced a sustainable solution is the Namib Desert beetle, which lives in southwestern Africa, one of the most arid places on Earth.
By extending its long legs and leaning its bumpy body into the wind, this small black beetle can collect droplets of water from the morning fog. The droplets combine until they are big enough to roll down the beetle's body, and are then channeled into its mouth.
This evolutionary innovation has inspired designers to come up with a system that uses screens to collect water escaping from the plumes of cooling towers at industrial facilities, with the potential to save hundreds of millions of liters every year.
The shape of the beetle's bumpy shell has also been used to create a mesh-like material that can be unfurled to gather water from the air in arid regions worldwide.
Undersea inspiration
As researchers venture further into the world's largely unexplored ocean depths, they're uncovering design secrets that have allowed aquatic life to thrive for millennia. Take the humpback whale, for example, which is known for being extremely agile despite its size. It sports a series of bumps or ridges along the front edge of its fins, known as tubercles.
Experts in fluid dynamics, who previously thought that wind turbines had to be smooth and streamlined for optimal performance, realized these bumps create tiny vortices that reduce drag and noise and help the fin cut through the water.
This revelation has led the way for new efficient designs for wind turbines, tidal turbines, airplanes, watercraft and surfboards.
Other, less mobile sea creatures have also contributed to sustainable design solutions.
Coral has a hard exoskeleton made up of calcium carbonate — essentially oxygen, carbon and calcium found in seawater. By imitating this process with captured CO2 from industrial plants, for example, the construction industry now has the possibility to make cement with a renewable, less wasteful method. At the same time, the process sequesters carbon emissions and prevents them from contributing to global warming.
Seaweed and other aquatic plant life, meanwhile, have given marine researchers a way to avoid the toxic chemicals normally used to prevent marine algae, bacteria and barnacles from covering and contaminating boats and coastal industrial facilities.
The surfaces of these plants have evolved coatings to make it difficult for microorganisms to gain a foothold. Shark skin also has similar properties, with its rough surface proving inhospitable to bacteria. This has influenced the design of new, antibacterial surfaces in places like hospitals.
Creating an 'emotional connection' with nature
Innovative solutions aside, Blasiak of the Stockholm Resilience Center sees another benefit to using biomimicry in everyday life — specifically as a way of helping people make an emotional connection with another life-form or ecosystem that they don't understand.
"And if you have that emotional connection, it's also a basis for caring and for stewardship and wanting to be more sustainable in your relationship with these ecosystems," he said.
