You, me, dogs, cats, horses, guinea pigs …

we're all mammals.

All part of one big, happy,

milk-producing family.

Other animals generally don't share the ability

to feed their young with a substance secreted from their own bodies…

With a few exceptions.

Like the Pacific beetle cockroach.

Yes, I said “cockroach.”

Now, let me start by clarifying that I'm talking about a milk-producing insect,

not a milk substitute made from insects,

which does exist but is a whole other, unrelated thing.

And I should also note that this stuff is not exactly milk—

at least not by the standards of the dairy industry—

since the roaches don't have mammary glands.

Plus, their babies don't nurse after birth

the way mammalian babies do.

so you can't just like,

squeeze them to collect a tube full of milk.

But these insects do produce

a special food for their young.

And that's how they're able to avoid doing something that most other insects do: laying

eggs.

Eggs can't exactly run from all the predators

that might make a fine meal of them.

So young insects that can move about the moment they leave their mother

have a bit of a leg up in life—

or, six of them, to be exact.

And the Pacific beetle cockroach

is the only known viviparous cockroach,

which means that females give birth to live babies.

They actually have a uterus of sorts called a brood sac.

And it's while a female is incubating her babies in this sac

that she produces a milk-like substance for her embryos to ingest.

This quote “milk” is a complete source of nutrition for the young cockroaches.

It's almost 46% protein,

including all of the essential amino acids, and about 25% carbs.

And it's a whopping 16 to 22% fat, which includes omega-3s and other “healthy”

fats.

Plus it's got vitamins and minerals.

So basically,

it's got a lot of everything,

which is why it has three times as many calories per gram as buffalo milk,

and some researchers say it's among the world's most nutritious substances.

And that gives the soon-to-be cockroach babies an evolutionary advantage.

During gestation,

Pacific beetle cockroach babies undergo a 50-fold increase in dry mass

from the time they arrive in the brood sac as fertilized eggs

to the moment they leave their mother's body.

That's so big that, at birth, the brood —

typically numbering around 12 nymphs —

can be one and a half times the weight of their mother.

And this whole process from embryo to nymph happens

three times faster than in other cockroach species!

They keep growing fast, too.

Males will reach adulthood after just three to four molts.

By contrast,

German cockroaches molt six times

before reaching adulthood.

And since the bugs are very vulnerable during and just after the molting process,

fewer molts means they spend less of their lives in this exposed state.

In fact, this milk is considered so nutritious that…

well, you may have already guessed where we're headed.

Yes, some have tossed around

the idea of mass producing cockroach milk for human consumption.

But alas, scientists and health-food moguls

have yet to come up with a practical way to harvest this stuff.

The roaches are pretty small,

and since the fluid is excreted into the brood sac not out into the world,

you can't exactly attach them to a milking machine.

To get the milk from the mama bugs,

researchers inserted filter paper into their brood sacs.

That soaks up the goods, which the scientists can then extract from the paper.

They can also cut open the young roaches to get at the stuff.

see, the liquid turns into crystals in the embryos' digestive tracts.

And those crystals can then be cut from their stomachs—

a process the roaches don't survive.

Either way, each roach only gives a tiny amount.

Experts estimate it'd take upwards of 1000 cockroaches to get 100 grams of milk.

That means you'd have to milk—

and probably kill—

countless cockroaches to produce an actual bottle of this stuff,

let alone enough bottles to sell to the masses.

Also, we don't actually know it's safe to consume in any quantity.

So, you won't see it on store shelves any time soon.

Researchers may one day be able to synthesize cockroach milk, though.

Still, even if that happens,

the milk is more likely to have medical applications

than it is to end up as a substitute coffee creamer.

Which is fine,

because we can always drink that milk that's made from insects instead…

Bottom's up!

Thanks for watching this episode of SciShow!

If you enjoyed it, I have a feeling you'll really like our podcast,

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It's a collaboration between Complexly and WNYC studios,

and it's hosted by several of the awesome people who work on SciShow.

Basically, they try to one-up each other

with awesome science knowledge about a given topic.

Like, there's an entire episode about how wonderful mucus is.

And snot gross at all...

Anyhow, we here at SciShow have a lot of fun making it,

and we hope you'll have just as much fun listening.

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[ outro ]