Now, 45 minutes sounds long until

you consider the brown antechinus.

For two weeks every mating season,

a male will mate as much as physically possible.

Sometimes having sex for up to 14 hours at a time,

flitting from one female to the next.

And all that testosterone revs up

his stress hormone production into overdrive.

That, in turn, crashes his immune system,

making him extremely vulnerable to disease and infection.

Oftentimes, he dies before his young are even born.

Scientists call this kamikaze mating

technique "suicidal reproduction."

It turns out that for many species, sex kills.

Take the male honeybee. His primary job?

Mate with the queen. But sadly for him,

he only gets to mate once

because during the act, his reproductive organs

are ripped off and his testicles explode.

In the process, his semen shoots

through her oviduct where she stores it for later use.

Hey, at least it's a quick death,

especially compared to some deep sea anglerfish.

Like the triplewart seadevil.

This one's a female, and you see

that tiny parasite on her side?

That's the male. It would be like

if a human male only came up to a woman's ankle.

Instead of hunting for his own food,

the male bites into the female,

fusing his body with hers and living

off the nutrients in her blood.

In return, he provides the one thing he has to offer: sperm.

But, there's a catch. In the process,

his body shrivels up. He loses his eyes, fins,

and most internal organs until ultimately

he becomes just a portable sperm bank for the female.

Fortunately, not all males have it that rough.

The short-beaked echidna survives mating,

but his sex life is anything but ordinary.

He'll line up with around nine other males

and follow a single female for up

to a month during mating season.

But here's the interesting part.

Females have a forked reproductive tract,

but that doesn't deter the males

because they have a four-headed penis.

So during sex, the male alternates,

swapping out spent pairs as each fires its semen.

And that semen is supercharged.

Hundreds of sperm glom together into bundles

which can swim faster than individual sperm,

increasing their chance of fertilization.

If that's not impressive enough,

his penis reaches nearly a quarter

of his body length when erect.

But that's nothing compared to a barnacle's.

That little crustacean has proportionally

the longest penis of any animal on Earth,

spanning up to 10 times his body size.

That's like humans reaching the length of a bowling lane.

And the barnacle needs it

because he can't move around very easily.

So he casts out his giant penis

like a fishing line to find a mate.

It waves about in the current,

reaching to touch and fertilize

the female organs of its neighbor.

Bee or barnacle, reproduction finds

creative ways to continue on.