Original subtitles

Narrator: Ever wondered how 1.5 million animals

Can hide from the world, undiscovered?

This is absolutely incredible footage.

Narrator: Why an ocean giant would hold a diver hostage?

And he was not going to let me get away.

Narrator: And what mystery critter

Would hoard acorns in the weirdest of places?

50 gallons of acorns came pouring out

In a great nutty avalanche.

♪

Narrator: Nature is awe-inspiring.

But sometimes, it just doesn't make sense.

Man: I have never, ever seen anything like this!

Narrator: Strange animal behavior,

Unexpected events captured on camera.

[ both screeching ]

The truth behind them is astonishing.

Man: My god!

Narrator: Nature's greatest mysteries solved.

-- Captions by vitac -- www.Vitac.Com

The cook islands in the south pacific ocean.

A hot spot for migrating humpback whales,

And a study site for whale biologist nan hauser.

♪

In September 2017, nan heads out

On what should've been a routine research trip.

Yet almost three decades of working with whales

Could not have prepared her for what was about to happen.

It was a beautiful day.

I was hoping that I could catch

Some underwater behavior of these whales.

♪

I never approach the whale or get too close to it.

[ whale sings ]

Narrator: Nan uses a camera to film the whale's behavior

To analyze later.

She is already recording when events take a dramatic turn.

One of the whales looked up and saw me...

...And he came right for me.

♪

He didn't stop.

♪

I didn't want to get rammed by a whale, so I put my arm out.

I knew I couldn't push

A 50,000-pound whale out of the way.

If they hit you with their fin,

They'll break your bones and rupture your organs.

I kept trying to get away,

And he was not going to let me get away.

Narrator: Her diving partner also catches

The whale's strange behavior on camera.

Nan has only a snorkel to breathe through.

No air tanks.

Hauser: He kept trying to hold me

And hide me under his pectoral fin.

And I was frightened, very, very, very scared.

Narrator: The whale's behavior becomes even more bizarre.

Hauser: He even lifted me up, out of the water,

And I was screaming to everyone on the boat,

"somebody, come save me!" [ laughs ]

Narrator: By now, nan has been struggling

With the whale for 10 long minutes.

Humpbacks reach up to 52 feet long.

Any wild animal this size is dangerous.

It could easily kill a human.

I think I was in such shock

That I didn't even put it together right away.

He was pushing me towards the boat the whole time.

I was completely baffled by this behavior.

Narrator: The whale allows nan to get back on the boat.

And she is elated to have survived the alarming encounter.

I love you, too!

♪

Narrator: But why did a 50,000-pound whale

Lift nan out of the water and push her towards the boat?

Clues may be found in the way

That humpbacks behave with other species.

[ ice cracking ]

In 2009, in antarctica,

Marine scientists were filming killer whale behavior

When humpbacks suddenly got involved.

Pitman: Killer whales were attacking seals on ice floes.

They are the largest apex predator we have

On the planet today.

They hunt cooperatively, much more so than other predators.

They group together and create a wave

That'll wash the seals off the ice floe.

♪

Humpback whales would come in

And start swimming around and seem to be agitated.

Weren't sure what was going on there.

Narrator: It seems that the humpbacks

Were deliberately going out of their way

To help the seal escape from the killer whales.

One of 'em rolled over

And lifted the seal up out of the water.

And you could see the humpback lift up

This one-ton flipper and nudge this seal

To the top of its chest.

Narrator: You can just see the seal center of frame,

Nestled in the safety of the humpback's chest.

And at that moment, we understood

That those humpbacks were there to break up

This predation event and to protect the seal.

In their minds, they wanna stop this attack.

Narrator: But what can this tell us about nan's encounter?

Could the humpback have also been trying to help her?

It's not without precedent

That humpbacks have intervened

To protect other species from potential threats.

Humpback whales have been seen to come in

And interfere with killer whales attacking seals,

Sea lions, whale calves,

And maybe, in the case of nan, a human being.

Narrator: Nan was in the whale's environment.

She could easily have been hurt because of its sheer size.

But the whale was careful to help her, not hurt her.

What we're seeing with this diver and the humpback whale

Could very well be some form of altruism.

Pitman: Altruism is sort of loosely defined as a behavior

Where the individual that's providing the behavior

Gets less out of it than the recipient.

Nosal: It may just be instinctual in the sense that

The humpback would normally do this behavior

To protect its own offspring.

But even in the absence of one of its own calves,

It still feels that overarching urge to protect.

Narrator: If this behavior is, in fact, altruism,

A form of protection,

What was the humpback trying to protect nan from?

♪

There were no killer whales in the area.

But towards the end of the encounter,

Nan spots something even more terrifying swimming close by.

The tail wasn't going like this.

It was going like this.

Oh, my gosh. That's a shark.

There's a huge tiger shark right there.

Narrator: Tiger sharks are second only to great whites

In the number of recorded attacks on humans.

Did the whale spot the tiger shark

Before nan did and protect her?

♪

Was the humpback really trying to protect the diver

From a tiger shark?

It's certainly possible.

After the encounter, the whale took off,

And so I just figured I'd never see him again.

But a year later, the whale came back,

And I screamed. [ laughing ]

I saw the tail fluke, and it looked just like

The whale that I knew from this encounter.

Narrator: Each humpback whale's tail fluke pattern

Is unique, like a fingerprint.

He came right to the side of the boat

And looked and me, and I looked at him,

And I just couldn't believe it was him.

[ whale sings ]

He nuzzled me, and I rubbed his face,

And we had a really nice little reunion.

Narrator: We may never know for sure what was really going on,

But it seems that this was yet another incredible example

Of a humpback whale saving the life of another species.

♪

January 2009.

Bear creek, california.

Residents complain that their tv signal has stopped working.

[ static crackles ]

An engineer arrives to try and fix the microwave antenna.

When he opens it up to investigate....

♪

50 gallons of acorns -- 500 pounds of acorns --

Came pouring out in a great nutty avalanche.

Narrator: Hardly surprising that it wasn't working.

It's like a tsunami of nuts coming out of this antenna.

♪

And so the question is, who or what would ever do this?

♪

♪

Narrator: In california, a faulty television antenna

Is found filled to the brim with acorns.

But whodunit?

♪

There's a prime suspect in the frame.

Squirrels. Obviously, squirrels.

♪

High level nut smugglers, the gray squirrel can stash away

Over 10,000 acorns in a single season.

Narrator: But did they store these acorns in the antenna?

Who better to help us figure it out

Than a scientist who spends her days

With these fluffy nut thieves?

I study the types of decision making processes

That animals make in order to survive.

Narrator: Stashing nuts is

Part of a squirrel's winter survival strategy.

And they're very picky about which nuts make the grade.

They'll check them over for cracks or holes,

Weigh them to make sure there's something inside.

And if it all checks out, they're gonna take it

To a location that they think is a little bit secretive.

And then what they're gonna do is they're gonna dig a hole

About an inch deep, and then they're gonna push

The food item into the side wall of that hole.

And they they'll grab leaves and other dirt

To camouflage to bury it for the future.

Narrator: Squirrels are great at hide and seek,

But did they fill the antenna?

We know grey squirrels are more than capable

Of achieving that volume of acorns over time,

But there's one big problem.

Most of them scatter their acorns

In many different hiding places.

They don't cache them into one single location.

Narrator: They use their memory and sense of smell

To find them again, although some are too well hidden

And never get found.

Scattering grey squirrels are not our culprits.

But another squirrel species could still be a suspect --

The red squirrel.

Greive: They do store their food in a single place,

In a midden, sometimes of enormous size,

Up to 20 feet long and 5 feet high.

Narrator: The world over, all red squirrels

Are location hoarders.

It brings all the food it's found and places it in one spot.

This mountain is food, not only for them,

But generations after them.

So they could be feeding their great-great-great grandkid

Off this giant mountain that they've built.

Narrator: What's more, red squirrels have a reputation

For stashing their food in weird places.

There is a story in north michigan

Of a guy who was driving down the road,

And his car was making all these sort of bizarre noises.

So he pulls over and lifts up the hood,

And in the engine, he finds 50 pounds of food.

So what could've put that there?

The red squirrel.

Narrator: It's looking like the red squirrel

Is a likely candidate to have filled the antenna.

But...

American red squirrels have a very simple diet.

They're just not that into acorns.

They don't eat acorns.

Almost always, they eat pine cones.

Narrator: Squirrels are off the hook.

So who else could it be?

It's time to widen the investigation.

Man: When I pulled the insulation off,

The walls are just filled with holes.

Narrator: Weird acorn stashes have appeared before.

In california, another hoarder has borrowed a pool house

To use as a food store.

Man: That's a lot of acorns.

Narrator: Could this stash help identify

Our antenna-hoarding culprit?

♪

♪

Narrator: In california, a faulty tv antenna

Is filled to the brim with acorns.

The usual suspects are in the clear

When another crime scene provides a vital clue.

The wall is just all these holes in it.

It looks like there's been a mafia hit.

Narrator: Could this evidence match our original case?

If you look at the cover of the antenna,

It's covered in all these tiny little holes.

Man: That's real, folks.

Greive: The numerous holes lead us to one key suspect --

The woodpecker.

Narrator: Woodpeckers --

The most determined birds of the natural world.

♪

Professor walt koenig has a good idea

Which woodpecker could be responsible.

He's studied these birds for over 40 years.

A lot of woodpeckers are mainly insectivorous,

Or almost exclusively insectivorous,

And they often will go deep into the wood,

Looking for grubs and larval insects.

But then when it's cold and wet and rainy,

They'll go for other things.

Narrator: Other things like acorns.

There's only one that we know of

That stores a large number of nuts --

The acorn woodpecker.

Narrator: The aptly named acorn woodpecker.

Go figure.

Acorn woodpeckers can just go to the granary,

Pick out an acorn, chop it up,

And feed little bits of it to their young.

So, they can do pretty well

Even when conditions are fairly marginal.

Here we have an acorn woodpecker granary

In a beautiful valley oak,

Somewhere around 500 years old.

Narrator: A granary is a store cupboard

That will last the whole winter.

All these holes are drilled by acorn woodpeckers,

And each one of them could be filled

By an acorn during the fall,

When they're harvesting the acorns and storing them.

It's extraordinary when you see a tree

That has been used as a granary by these woodpeckers

Because they're just full of holes.

In fact, the biggest one ever found

Had over 50,000 holes in it.

Narrator: They reuse these granaries season after season.

Acorn woodpeckers, they work collectively

In families of up to 15 birds.

Narrator: But the acorns in the antenna

Would've been impossible for the woodpeckers to retrieve,

As they were trapped behind a metal casing.

So why did the woodpeckers go so nuts pushing them in there?

Acorn woodpeckers are not real good

At sort of figuring out where acorns go

If they go into a hole and disappear.

So I think you have young birds

That put these acorns in these holes.

And if they disappear, they don't really care.

They just go get another acorn and keep putting 'em in there.

Narrator: There you have it.

Hoarding woodpeckers are

The acorn-obsessed trouble makers.

♪

March 2014.

A nasa satellite orbiting earth picks up strange patterns

Off the coast of antarctica.

Computer algorithms alert scientists,

Who deploy a drone to investigate.

They discover black dots,

Stretching as far as the eye can see.

The dots turn out to be...

Penguins.

In one of the most remarkable natural history discoveries

In recent years, 1 1/2 million adélie penguins

Suddenly appeared on danger island,

Off the east coast of the antarctic peninsula.

Narrator: The big question is,

How come we didn't know they were there?

♪

♪

Narrator: On the danger islands in antarctica,

Satellite images and drone investigation

Revealed a colony of 1.5 million adélie penguins,

Hiding in plain sight.

Until 2014, we had no idea they existed here.

In the western antarctic peninsula,

Adélie numbers are plummeting due to climate change.

But now it turns out that the tiny danger islands,

Just beyond its tip, are home to more adélie penguins

Than the rest of the peninsula combined.

The question is, how did we miss them?

Burke: Did the colony spring up in record time?

Could this be a new colony of adélie penguins

That has enjoyed an explosive birth rate?

Narrator: Probably not.

Penguins are relatively slow breeders.

[ both calling ]

A female will lay one to two eggs a year,

And those eggs are incubated over 30 to 40 days.

So these aren't exactly baby boomers in bird terms.

[ calling ]

Adélies generally only have one chick a year,

And one-quarter of those chicks don't make it to adulthood.

Therefore, it would take many centuries

To reach a colony size of 1.5 million penguins.

Narrator: It seems they didn't populate over night.

Have they recently moved here?

Could these adélie penguins have migrated from elsewhere?

I mean, it's certainly possible.

Penguins have been known to cover

Some really vast distances.

Narrator: At only 27 inches tall,

Adélies are one of the smallest penguins in antarctica,

But they're tougher than they look.

Every year, they travel up to 11,000 miles

In search of food.

They're not exactly elegant on land.

But in the water, they transform.

Burke: In theory, the adélies could have migrated there,

But there's a vital clue right underneath

The scientists' feet.

So scientists radio carbon dated

The remains of eggshells and bones

That they found on the island, and what they discovered is that

This adélie penguin colony had been there

For over 2,5000 years.

They were always there.

Burke: With new technology,

With satellite imagery, and also drone technology,

It meant that we can explore these really remote islands

To discover that the penguins were there all along.

We still wouldn't have found them

If not for nasa satellites

Spotting their guano from outer space.

Narrator: "guano" is the fancy scientific word

For bird droppings,

The strange marks on the landscape were penguin poop,

Which gave away the adélies' hiding place.

Modern technology is revealing just how much

There is left to discover about our planet.

Captions paid for by discovery communications

♪