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Termites, prairie dogs, and people are all great builders, each in their own way.
And we all share one crucial problem.
Put a bunch of us in a closed space, breathing Oxygen in and CO2 out… and it doesn’t
end well.
Our tallest skyscrapers and deepest mines are almost completely cut off from outside
air.
To keep those inside from suffocating, human engineers use giant machines to bring in fresh
air and pump stale air out.
Termite mounds have the same problem.
The largest are more than 10 meters high.
On a human scale, that’s like a skyscraper three and a half kilometers tall!
Only instead of condos and offices, it holds one big farm.
The termites collect wood, which grows fungus, that the termites eat.
All that fungus and the millions of termites that tend to it create a ton of CO2, which
would suffocate the colony *and* their crops if it builds up.
To keep the air fresh, the whole mound acts like a big lung.
During the day, the sun heats the outer chambers more rapidly than the core, moving air up
the outside and down the middle.
During the night, this current reverses as the outer chambers lose heat to the cool night
air.
The whole time, CO2 and oxygen are exchanged through tiny holes in the outer walls.
What’s amazing is this is all constructed without a boss.
No central architect designing the structure.
Just instinct and cooperation lets termites build huge ventilation engines powered by
nothing but daily temperature cycles.
Leafcutter ants farm fungus on massive scales too.
One colony in South America covered nearly 50 square meters and was home to over 8 million
ants!
But unlike those towering termites, the ant labyrinth reached 8 meters underground.
So how do they ventilate their agricultural city?
Before we answer that, I want you to try something.
Take a piece of paper, hold it under your lips, and let the other end curl down.
If you blow only across the top of the paper, what do you think will happen?
The force of the air hitting the paper should push it down, right?
Well watch this.
Here’s what’s happening: Air is a fluid.
When I force air across the top of the paper, that stream pulls other air along, due to
viscosity, which is like the friction of fluids. This leaves an area of low pressure
behind, and the paper is pulled up to fill it.
This is called the Coandă effect.
What does that have to do with ants?
Check this out.
When a breeze flows over a hill, the air is deflected over the top.
This pulls air along too, just like when I blew over the paper,
drawing air out of the ant hill along the way.
The ants build lower entrances nearby, where air is drawn in to replace it, ventilating
the whole colony with a little breeze.
Prairie dogs get the same effect from their mounds.
Breezes over taller hills draw air through the connected tunnel system, keeping the whole
town breathing fresh.
There’s even a tiny shrimp that uses this same system to keep fresh water flowing through
its burrows.
Persian and Egyptian architects have used similar structures to cool buildings for centuries,
but tiny animals beat us to that technology by millions of years
Nature is full of species that build their environment to suit them, countless expert
animal architects.
Sometimes, all you need to solve the most complex engineering problems is the awesome
power of evolution,
…and that’s a breath of fresh air.
Stay curious.
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