Engineers often take inspiration from nature for their creations. But we sometimes overlook the incredible engineering and architectural skills of animals in their environments.
It’s well-known that the way a kingfisher breaks through water inspired an iconic element of Japan’s bullet train — the nose. The innovation came about when Eiji Nakatsu, an engineer with JR West and an avid birdwatcher, was trying to lower the noise level of the world-famous Shinkansen, which exceeded environmental standards.
He turned to the small, brightly coloured birds found in the tropical regions of Africa, Asia, and Oceania. One of the great avian hunters, the kingfisher hovers above water until it sees its prey. The aerodynamic build of its bill and head means that it makes almost no splash as it slices through the water.
The kingfisher’s bill is just the right shape to act as a wedge, starting at a point and its diameter slowly increasing until it reaches the skull. This shape pushes water out of the way, rather than ahead of the bird — precisely what Nakatsu and his colleagues wanted to accomplish with the air surrounding the 320 km/h bullet train.
That wasn’t the only feathered friend that inspired the Shinkansen design. Engineers reduced the pantograph’s noise by adding structures to create many small vortices — similar to the way an owl’s primary feathers have serrations that create small vortices instead of one large one.
But while it was the aerodynamic nature of the kingfisher that inspired Eiji Nakatsu, some animals also act like engineers.
Semi-aquatic ecosystem engineers
Beavers are known as ecosystem engineers, because of the way they construct complex dams that trap substantial amounts of water, creating large ponds that are key for their survival.
The semi-aquatic rodents can cut more than a tonne of wood each year, and alter the makeup of waterways through the amount of carbon and nitrogen that is recycled. This, in turn, can alter the biological diversity and change the local vegetation.
But they’re an environmentally friendly species — beaver dams can help make wetland ecosystems more diverse, recharge aquifers, absorb pollutants and act as a buffer against both flood and drought.
Ants march science forward
With a week and pile of dirt, an ant colony can build the equivalent of a skyscraper on an ant-sized scale. For context, it took humans 13 months to build the Empire State Building, and we tend to take a lot longer now.
Research that combined computational modeling, modern imaging techniques and behavioural observations found that ants build their complex structures by obeying three basic guidelines governing when and where ants pick up and drop off their building materials.
Ants pick up grains at a constant rate of approximately two grains per minute, they prefer to drop them near other grains to form a pillar, and they tend to choose grains previously handled by other ants, probably because of marking by a chemical pheromone.
Using these rules, the researchers were able to reconstruct ant behaviour in a computer model.
Bowerbirds, the most stylish engineers
In order to attract a female mate, bowerbirds build and decorate elaborate nests called bowers. These are constructed with twigs, brightly-coloured objects, fresh flowers and even iridescent insect skeletons. The objects are deliberately placed to put on the most impressive show for the local ladies.
Different species tend to focus on different colour schemes, with the satin bowerbird attracted to blue objects because it reflects its colouring, which in turn entices the right mate.
The duller the colour of the male, the more beautiful the bower. The Vogelkop gardener bowerbird builds one of the largest and most elaborately decorated of all bowers: a hut-like structure more than 150 cm high and 180 cm wide.
American mathematician Thomas Hales wrote a proof showing that bee hives are the most efficient structures in nature.
Hales explains the honeycomb conjecture — the mathematical concept that a hexagonal grid is the best way to divide a surface into regions of equal area with the least total perimeter.
Bees are nature’s great example, with Hales proving that the hexagon tiling of honeycomb is the most efficient way to maximise area while minimising perimeter. It all has to do with bulging — and Hales showed that the advantage of bulging out is less than the disadvantage of bulging in, with hexagonal shapes doing best in this regard.
For more on nature and engineering, check out these examples of biomimicry in action.