- [Narrator] There's a creature scurrying
across your face right now. Yes, you,
and at some point, maybe now, maybe in a few days,
it's going to find a nice cozy pore in your skin
and lay a single enormous egg.
Meet the face mites. They're smaller than a grain
of sand, are a kind of arachnid like spiders,
and they feast on the oil and cells in your skin,
particularly on your oily nose, cheeks, and forehead.
Scientists suspect they've been living on us
since the dawn of humanity over 200,000 years ago,
and today, studies suggest practically every adult
on the planet has thousands of them.
Odds are you've been living with them your whole life.
Babies quickly get them from their parents
a few days after birth, and once those face mites
are on you, the only thing they enjoy as much
as slurping oil and nutrients from your pores is
having sex all over your face.
Afterwards, females burrow deep
into your pores where they lay their eggs.
The eggs end up in one of two places
depending on the species of face mite.
The first species, called Demodex folliculorum,
lays its eggs in your hair follicle,
while the second prefers nesting in your sebaceous glands.
And in under two weeks, the babies hatch,
mate, lay their own eggs and die,
leaving behind a pile of decomposing corpses.
Now, you can wash some of this off,
but you'll never eradicate them completely
because even if you treat them with antibiotics,
they'll return in about six weeks, tops.
You'll pick them up from towels, pillows,
and your loved ones.
Well, that all sounds horrific,
but usually face mites are harmless.
They only become a problem when they multiply
out of control. This can happen in people
with an impaired immune system.
It's also been seen in people with a painful skin
condition called rosacea.
Normally, you'll have around one or two mites
per square centimeter of skin,
but one study found that people with rosacea
had 10 times the normal amount.
Believe it or not, in some cases,
face mites can be useful.
Researchers can actually study your face mites
to learn about your ancestors.
You see, most mites often stay within a community.
So over time, they've evolved into distinct lineages
in different geographic regions, and by comparing
their DNA, scientists can trace how different groups
of humans migrated across the world.
For example, a study found that European mites
genetically diverged from East Asian mites
around 40,000 years ago.
That's the same time European and East Asian humans
parted ways. Pretty handy.
So when it comes down to bugs crawling all over you,
it could be a lot worse.