Narrator: At first glance, a fire ant hill -
or mound, as it's properly called - looks impossibly small.
And yet a colony of up to 250,000 ants call it home.
But here's the secret: that mound
is just the tip of an enormous iceberg.
So let's take a closer look at what's inside an anthill.
The mound is really the top
of an enormous underground structure: the nest.
Which is basically a giant nursery: a nice, cozy place
to raise babies. A lot of babies.
Their mother, the queen, roams around the nest
while laying 1,500 eggs a day!
Now, all those baby ants need to live
in a narrow temperature range to grow.
So that nest sports temperature-controlled rooms.
And it does so without the help of an AC unit.
The secret's in the design.
The nest is arranged like an ice cream cone.
At the top, you have the mound - the ice cream, as it were.
Because it's above the surface,
it warms up from the heat of the sun,
so the babies can snuggle up in toasty chambers
networked throughout the mound.
But they can't stay there all day,
or they'd get too hot.
That's where the cone part of the ice cream cone comes in.
The mound is connected to several vertical shafts
that plunge up to two meters beneath the ground.
That's taller than most humans.
Throughout the day, adult ants ferry the babies
up and down the shafts, chasing that perfect temperature
for their young charges.
The nest also sports dozens of tapering tunnels
that branch off from these main shafts.
These connect to small chambers where the ants rest, eat,
and feed the babies until it's time
to move the little ones once again.
Now, there's one more type of tunnel inside the nest,
but only a few ants ever use it.
You see, someone needs to find food
for the rest of the colony,
but running around outside the nest is dangerous business.
That's where forager tunnels come in.
These are a couple of horizontal passages
buried just a few centimeters from the surface.
But they run throughout the entire territory,
which can cover up to 185 square meters of land.
By scurrying through these passageways,
the scouts can stay underground as long as possible.
But unfortunately, the nest and all its roads
can't protect the ants from every threat.
It turns out all sorts of critters
sneak inside fire ant nests.
And while many of them are actually harmless,
others are horrible houseguests.
For example, beetles burrow into the nest
and devour the eggs and larvae.
But invaders aren't the only threat to the colony.
Occasionally, clueless humans
or major floods disturb the nest.
And when that happens,
the fire ants have only one option, leave.
Once a year on average, the colony will move out
and build an entirely new nest from scratch.
And best of all, they only need a few days to do it.
That's right. Practically overnight,
meters upon meters of tunnels can pop up in your yard.
And all you'll notice is a tiny mound.