Death might seem like the end.

But for these five creatures, death is how they make a living.

Flesh eating beetles strip meat from bone.

Whispering bats stalk their prey by listening for the faintest sounds in the dark.

While owls fly so quietly that their victims never know what hit them.

And black widows have a deadly reputation, but there's more to the story.

First, see how crows hold funerals to learn from their dead.

A verdant park, an idyllic day.

But something has gone terribly wrong.

A passerby discovers it first and lets out a piercing call.

Within seconds, everyone in earshot rushes to the scene.

It's mayhem, or so it seems.

Crows are intelligent.

And super chatty.

They watch out for one another within tight-knit groups.

As adults, it's pretty rare for crows to be killed.

So when one dies, the others notice.

Are they just scared, or is something deeper going on?

Kaylee Swift, a PhD candidate at the University of Washington set up an experiment to find out.

She visits a park in Seattle for a few days, leaving piles of peanuts for the crows.

Then, one day Swift shows up looking very different.

Wearing a mask and wig, she carries a dead taxidermied crow.

The first one that sees her sounds, the alarm, the flock erupts in protest.

The crows seem to wail and scold her and the dead bird.

Swift calls these "crow funerals".

Though they're not the solemn memorials we put on for our dead, she thinks these noisy gatherings are opportunities for crows to learn about the dangers that surround them within the safety of the group.

When an unmasked swift returns to the park the next week with more tasty peanuts, the crows are quiet and wary.

They seem to have learned there's something hazardous about this place.

Still, they eat the peanuts, but they take longer to approach and seem to be much more suspicious.

And when Swift returns wearing the mask, they lose it.

Even without the dead crow, they still see her as a threat.

Compare that to these pigeons.

They barely seem to register for holding their deceased comrade.

That's how most creatures react.

Just a few like dolphins, elephants and crows react strongly to seeing one of their own who's died.

Even weeks later, the crows cause a ruckus when they see the mask.

Some never even saw her with the dead crow, but they still learn to associate her with danger.

It's called social learning, gaining new information by observing and imitating others.

We are always looking to learn from one another too, to avoid the mistakes that led others to meet their untimely end.

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Up next, whispering bats find their prey by creeping through the dark, listening for the faintest sounds.

Slicing through the shadows, scanning for prey hidden under a cloak of darkness.

That's our masters of the night sky, thanks to their twin superpowers: flight and echolocation.

Using sound waves to find prey.

So what the heck is this one doing?

It's hunting on the ground and not flying.

Kind of an undignified way to catch a meal, isn't it?

I mean, for a bat.

Turns out echo location, that natural sonar bats use, isn't the killer technique you'd think.

Like, it's not actually that sneaky.

We can't hear the frequency that bats put out, but to a moth, it's louder than a scream.

More like a jet taking off.

It's kind of a dead giveaway, and some prey have found ways to fight back.

This tiger moth has loaded up on a diet of toxic plants that make him disgusting to eat.

A fact he broadcasts with warning clicks from an organ called a tymbal.

The same one cicadas used to sing.

Bats learn as pups to stay away.

And these hawk moths can scramble bat sonar... by emitting clicks from their genitals.

It's a dog fight that bats are starting to lose.

That's why some like this pallid bat are changing the game.

She still echo locates but only to navigate, and she keeps the volume low.

She's a whispering bat.

When it's time to hunt, she goes into stealth mode.

Her ears point down where scorpions and crickets are milling in the loose earth and she listens.

Look at those ears again.

They're huge relative to her tiny skull.

They do a great job of capturing and amplifying sound, especially the low pitch noises of scurrying prey.

And see that funny flap?

It's called the tragus.

They provide extra information about where a sound is coming from.

We have them too, but in a bat they're way bigger.

And the bat has a final card to play here.

She's immune to scorpion venom, but the sting rattles her a little.

It's not as graceful as the high flying aerobatics, but hey, it works.

If you can stomach more, see how scientists use this beetle's taste for death to help them study life.

Death and decomposition are the parts of our biology we try hardest to forget.

But to study life, you've gotta look death in the face and try if you can, to contain it.

The Museum of Vertebrate Zoology at UC Berkeley has mastered the art of preserving dead things.

They call this the Library of Life.

It's an enormous collection providing future generations of researchers a window back in time.

But specimens don't look like this when they get here.

They still have flesh, skin, and eyes.

These scientists receive hundreds of carcasses a year.

It's their job to preserve each animal for long-term use in the collections upstairs.

And the work is not for the squeamish.

They carefully remove skins to be stuffed, take flesh samples and record stomach contents.

The final challenge is to clean the flesh from the bones without damaging them.

And to do this, preparers rely on an unlikely ally - flesh eating beetles.

These dermestid beetles are direct descendants from the original colony established in this museum in 1924.

The process was pioneered here.

In nature, these charming little creatures are death homing devices.

They find a dead body about a week after death and lay eggs in the drying flesh.

The larvae emerged with a voracious appetite outgrowing their skins six to eight times in just days.

What makes dermestids ideal for this job is that they're fast and fastidious eaters.

They can pick a carcass clean while leaving even the most delicate structures intact.

But the alliance between beetles and museum is an uneasy one.

Downstairs, the beetles are a critical tool, but if dermestids get loose upstairs, they can wreak havoc in the library stacks munching through the specimen drawers and ruining entire collections.

That's what happened here.

So museums try and keep a firewall between upstairs and downstairs, between death and decomposition.

And if you think about it, so do we.

Consider the modern coffin, designed to ward off decay.

But decomposition is part of life too, and in the end, the bugs always win.

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Next up, see what makes owls so quiet their victims don't hear them until it's too late.

This owl is an ambush hunter.

What makes her so deadly?

She's not the fastest, but she has a different advantage.

It's stealth, not speed that makes her lethal.

Compare this owl to a falcon.

Both animals are birds of prey, but they have really different strategies when it comes to hunting.

The falcon hunts when it's light out.

He's incredibly fast.

Some falcons fly up to 200 miles per hour.

They don't need to be quiet.

By the time their pray hears them, it's already too late.

But owls have another strategy.

They hunt under the cover of darkness.

They're sneaky.

She has incredibly powerful night vision, and she can zero in on the location of even the smallest noise.

Air rushes over her wings as she flies in most birds, that's noisy.

But with owls, there's almost no flapping sound, no rustling.

It's quiet.

Up close, you can see how she does it.

Her feathers are velvety, soft.

That furriness lets the feathers slip quietly past each other during flight, dampen sound like a soft blanket.

Compare that to falcon feathers.

They're sleek and aerodynamic, but noisy as they slice through the air.

And here's another thing.

See those projections along the leading edge of the owl's wing like a pointy comb?

Those break up the wind as it flows over the top of the wing.

The feathers at the trailing edge of the wing break up the wind even more.

Compared to a falcon, these feathers look kind of jagged, right?

But that jaggedness means almost no whooshing sound that would alert their prey.

And overall owl wings are bigger, wider than a pointy falcon wing.

So they're slower, but they have more lift.

The owl doesn't need to flap them as often.

Less flapping means less noise.

We often fear what's fast.

Speed and danger seem to go hand in hand, but owls have given up on racing through the day to become champions of sneaking through the night.

The female black widow is a symbol of death.

But what if I told you she doesn't really deserve the bad rap?

You know what people say about her.

She's the black widow.

She mates, and then she kills.

Right?

Here comes her victim now.

He's smaller, less venomous.

Kind of cute.

Sweet little guy.

But before he gets eaten alive, let's talk about this poor sucker for a minute and how much of a victim he really is.

This western black widow lives in California.

She works pretty hard to make a living.

Unlike many spiders that build a new web each night, she toils continuously on the same one her whole life.

This web may look messy, but don't be fooled.

It's laid out on a grid of drag lines that she attaches to the ground.

It's a multi-story sticky trap that stands up to some pretty tough game.

When she bites, the venom takes hold, bringing a slow paralysis, as this lethal knitter wraps, and wraps, and wraps.

But that's not the only thing hanging around the web, there's this guy.

Adult male widow spiders don't build webs of their own.

He moves right into hers.

Basically, he's a squatter.

He's staking his claim to her because he knows every sticky thread of the web is covered in her pheromones, and that spreads her mating scent far and wide, potentially attracting a nice selection of other males for her to choose from.

Which is not on his agenda.

So, he trashes the place.

He goes around snipping strands of her web, undoing all her hard work.

He winds up the loose threads in his own silk, masking her scent from other males in the area.

It's called web reduction.

When he finally tries to mate with her - see that vibrating?

That's him signaling his interest.

He wraps her limbs in his own delicate silk.

It probably serves to surround her in his pheromones.

Scientists call it the bridal veil.

It seems to subdue her, makes her more approachable.

When they mate, he leaves behind a piece of this curlicue-shaped organ, called an embolus, in her body.

It blocks other males from fathering her offspring later.

So let's see.

Lazy, rude, messy, controlling.

Okay, now let's watch him get eaten.

Actually, in most widow spider species, the males don't get eaten.

They escape scot-free.

The Australian redback is one of only two where cannibalism almost always occurs when they mate.

He literally somersaults himself towards her mouth so she can take the first bite, which keeps her interested.

Scientists describe it as a self-sacrifice.

And she'll take her time, devouring his insides later.

Least he can do, right?