Original subtitles

Narrator: We know a leopard can't change it's spots,

But what about giraffes?

Midcap: It really does look like a mythical creature,

Where did this come from?

Narrator: Why are millions of birds creating

Crazy patterns in the sky?

But if that was a group of humans, it would be chaos.

Narrator: And if cheetahs are the worlds

Fastest land animals...

Everything about these animals is built for speed.

Narrator: ...How come they some time give up the chase?

What the heck is going on?

Nature is awe inspiring,

But sometimes it just doesn't make sense.

I have never seen anything like this.

Our team of experts investigates the weirdest animal behavior.

It's amazing.

Narrator: And a most unexpected events...

What is causing that?

Narrator: ...Ever caught on camera.

Man: My god.

Narrator: These are...

August 2017.

Ishaqbini hirola conservancy, kenya.

Rangers come across an unusual sight.

A giraffe and her calf but neither have any

Of their signature markings.

Baker: Well, this clip is phenomenal,

I mean to see a pure white version

Of anything that shouldn't be white

Is always incredible.

Midcap: So this isn't just a giraffe with faded

Coat coloration, this thing is white.

Tall, beautiful, looks like it's in perfect health.

It really does look like a mythical creature,

Where did this come from?

Narrator: To find out what's going on,

We need to know more about the regular giraffes

We're used to seeing.

Burke: Giraffes are famous for being these long=necked,

Long-legged, graceful animals.

And more than anything their pattern as well,

Is very, very distinctive.

Narrator: Giraffe species have varied markings

But the reason for these patterns

Has been puzzling scientists for some time.

Burke: The darker patches actually have more blood vessels

Than the lighter patches.

And we think this might have something to do

With dissipating heat.

But it could also have to do with releasing pheromones

As well to attract mates for example.

But there's other theories

That the reticulated pattern breaks up

The outline of the animal, it just breaks up

Any lines and possibly works as camouflage.

Narrator: As with other animal patterns

It's slightly a combination of all these things

That give the giraffe their unique markings.

But how is it these ones have no color at all?

Midcap: Could it be that this giraffe is albino?

Albinism is a condition where one or more traits

Are handed down to an animal that prevents melanin

From being produced in the organs.

Narrator: Melanin is the pigment that gives skin,

Hair, and eyes their color

But with albinism hair and skin is white

And the eyes are pink as the blood vessels in the iris

Have no pigment to mask them.

So the coat of a giraffe would depend on the production

Of melanin if you were to see all

Those beautiful colorations

But in this case there aren't any.

Albino creatures can be found

Across a vast spectrum of the animal kingdom.

From white moose,

To white wallabys,

To white barracuda.

So it's quite prevalent, although it is

A fairly rare condition, it does affect the majority

Of the animal kingdom.

So I guess the simply conclusion would be,

Oh, it's an albino giraffe, isn't that exciting,

End of story.

But actually if you look closely, this giraffe

Doesn't have the pink eyes, it actually has dark eyes,

So it's not an albino.

Narrator: An albino giraffe is ruled out

So what else could have created this ghostly giant?

Burke: There's another explanation as to why

This white giraffe exists,

And it's a skin disorder called vitiligo.

And it's a condition whereby over time,

The skin is unable to produce melanin.

Narrator: With vitiligo the bodies immune system

Attack it's own melanin cells by mistake,

Gradually creating white skin.

Midcap: It is very rare in the human population,

Only about 1% to 2% of humans have this.

But in the animal kingdom it's even more rare.

Narrator: Rare, yes,

But it has been seen in giraffes before.

A giraffe that was filmed in sunburu in kenya

Had this skin disorder, vitiligo.

Midcap: So could it be possible that this giraffe

Also has vitiligo just like it's kenyan cousin?

Narrator: Her offspring's white coat makes it unlikely.

If it was vitiligo you would expect that youngster

To start off normal and get slowly paler.

Narrator: The fact that this young calf is white

Just like it's mother, rules out vitiligo.

But if the giraffes are not albino

And don't have vitiligo, what is the reason

For their white color?

There's only one real thing that it could be

That's left and it's a beautiful and striking thing

When it happens, but it is incredibly rare,

Which is leucism.

So what you've got here is a leucistic individual.

Narrator: Leucism is a genetic condition

Where animals are born with the loss of some

But not all pigment.

Eyes and hair can still have color,

But the skin is often very pale.

The condition effects as few as one in a thousand

And when you do see these animals,

They are unmistakable.

I've seen it in deer population, near where I live.

A lot of zoos famously have white tigers,

Those are leucistic tigers.

And they're still rare and it still produces

The most peculiarly beautiful mutations.

Narrator: Zoos often adopt leucistic animals

As being without pigment means their chances

Of survival in the wild are pretty slim.

Imagine being a white bird in a wood full of sparrow hawks

You're gonna stand out,

You're gonna be the target number one.

Narrator: But coloration isn't only used for camouflage.

Burke: Pigments have multiple functions,

The pigments will sometimes impress mates

But really fundamentally pigments also help

To protect from uv radiation from the sun.

So albino snakes for example, they don't fare very well,

Partly because they can't thermo regulate,

But partly because they're really exposed to uv radiation.

Any animal that relies on pigmentation

Is quite unusual for them to survive into adulthood.

Narrator: So this sighting of white giraffes

Is particularly special.

Midcap: White giraffes are exceedingly rare.

We don't know how many exist in the wild

And this is only the second one ever spotted

In this national park.

So that's the real magic in this footage

Is not only has this animal survived,

It's actually got offspring as well, so it's managed

To successfully breed.

Narrator: While the deck may be stacked against this

Beautiful and unusual pair of giraffes,

So far, they're beating the odds.

Burke: For now at least, this female and her calf

Are doing really really well.

♪

Narrator: The oxfordshire countryside, uk,

February 2016.

Tens of thousands of starlings have flocked together

And are flying in elegant patterns.

Nelson: Its like a symphony in the sky.

It's almost like flowing water.

It's unlike anything that you've seen before.

Aryee: Oh, that's cool.

It does look like one entity, one organism.

I've always amazed at how intricate and how much

Of a dance a murmuration really is.

I absolutely love them.

Narrator: Murmurations, the term used

To describe this phenomenon,

Are seen all over the world.

But we still don't know the bigger question

Which is why?

Narrator: Around the world, bird watchers are capturing footage

Of murmurations, the gatherings of immense numbers

Of starlings that fly in intricate patterns in the sky.

So the question remains, why do starlings

Murmurate in the first place?

Narrator: To unravel the mystery of murmurations,

We need to figure out how so many birds

Up to six million, can move together.

If that was a group of humans it would be chaos.

Narrator: But it's one starling mirroring the movements

Of the surrounding birds

That keeps the murmuration on course.

All you have to do is keep track of who's in front of you

Who's to your right, who's to your left,

Maybe who's above you.

And if those seven individuals are coordinated

The whole group moves in unison.

It's fascinating.

♪

Narrator: And that's not all,

The staggering speed with which they respond to each other

Has also only recently been discovered.

Aryee: A team in rome found that starlings are able to respond

To the movement of another starling next to it

Within a hundred milliseconds, so that quickly.

Nelson: So now we know the intricacies of a murmuration,

But we still don't know the bigger question,

Which is why are so many birds doing this formation?

Narrator: One clue might be the fact that we often

See these formations at dusk, when the temperatures drop.

♪

Daly: So some researchers believe that murmurations

Are a signal to other birds so they can all gather

In bigger numbers and be warmer.

Aryee: Temperature to me seems like a very plausible reason.

You know, if you're a tiny bird, you want to recruit

Loads of other starlings to come and roost with you,

So you can share that body heat.

Narrator: But murmurations happen

At all times of the year,

Putting the temperature theory in doubt.

Nelson: The problem is that it's not that they're murmurating

Only on cold days,

They're actually murmurating more on warmer days.

So it makes sense that they're not necessarily

Communicating, hey, it's cold, join their group.

But maybe they are communicating something else.

Narrator: Could this instead be a sophisticated way

Of spreading a message through the flock?

Nelson: If you've ever stopped and looked at one

Of these murmurations, you would also hear it,

It's very loud.

[ birds chirping ]

So potentially, they're tweeting to each other

Where the food is.

Aryee: We see this behavior in the blue footed booty,

You have a leader as it were,

That let's out a loud squawk and that then signals

To the other blue footed boobies

That it's time to feast,

And they all dive simultaneously into the water.

♪

It's thought that this increases the chances

That each bird is gonna catch a fish.

♪

Narrator: But for starlings, sharing food information

On such a massive scale just doesn't add up.

Nelson: In a group this size, if you found food,

You might not want the entire group to know

Where it was.

I mean, we're talking thousands and thousands of birds

Because then you'd be out of food.

Narrator: Communication is ruled out,

So what is the reason starlings murmurate?

Daly: When we analyze a starling murmuration

There's often one thing that's fairly evident,

That's the presence of a predator.

Narrator: For years, scientists have been trying to get

To the bottom of why starlings murmurate.

They then noticed the gatherings of these starlings

Often had one thing in common -- a bird of prey.

So are the starlings murmurating to avoid predators.

Narrator: To find out, we visited anne goodenough,

A biologist who's been studying starlings for years.

To ask her if predators could be the cause.

There's a link between size of the murmuration

And the number of predators present and their activity.

We found that when you got predators that were flying in

And around the flock you tended to get bigger murmurations

And the birds stayed up a lot longer.

Narrator: Anne thinks murmurations are likely to be

A strategy that starlings use against predators

Like falcons, eagles, and hawks.

Goodenough: So when a predator flies into a starling flock,

It will try and get focus lock on one specific individual

And go in after that one specific individual,

Exactly in the way that a targeted missile would work.

If that individual is part of a swirling 3d mass,

It's much more difficult to get and maintain focus lock

And ultimately hunt successfully.

Narrator: Footage of a predator attacking the murmuration

Show this defensive technique in action.

Goodenough: That looks like a peregrine falcon,

And you can see that as it's diving in and through the flock

The birds are reacting to it's presence.

The birds are repelling away from that,

Just like iron fillings when they're exposed

To the wrong end of a magnet.

And this is one of those key ideas for why

Murmurations occur in the first place.

And actually this falcon isn't doing terribly well,

It's flying in and through the flock,

But it's actually not being successful

In catching it's dinner.

Aryee: For these starlings are gathering

In these huge murmurations,

They are trying to deliberately confuse

A potential predator and this is called

Predator confusion theory.

Narrator: But during murmurations,

It's not just predator confusion that's at play,

The sheer numbers involved in it

Means the starlings are also employing

What scientists call, the dilution effect.

The dilution effect, essentially is safety in numbers.

Nelson: It's simple math.

If you're one lone individual,

And you see a predator, you're chances are pretty high

That you're gonna get chomped.

But if there's a thousand more of ya out there,

You decrease your chances by a thousand.

Narrator: So for starlings, a murmuration

Isn't just a dance in the sky,

It's an effective aid in survival.

♪

August 7, 2015, hwange national park, zimbabwe.

A tourist is recording his safari adventure,

When his tracker spots a hunt in progress.

And the hunter isn't just any predator,

It's the cheetah, the fastest land animal on the planet.

♪

This cat goes from zero to 60 miles and hour

In just three seconds.

Burke: Everything about these animals are built for speed,

They have this lightweight skeleton,

Really long legs,

Which allows them to take these huge strides.

They even have a specialized inner ear canal,

Which helps to keep their head completely fixed

On their prey.

And then a really long tail which acts like a rudder.

Galante: Cheetah have incredible flexibility

That allow them to pivot on a dime and they can withstand

G forces that would break a human beings leg.

Narrator: Their prey doesn't stand a chance.

But hang on a second, the cheetah's given up.

Why?

Cheetahs often throw in the towel

Even when it seems their prey is in range.

Burke: So with all these incredible adaptations

Begs the question, why are only 58%

Of their hunts successful.

How is that possible?

Narrator: Footage shows that the cheetah,

The world's fastest land animal, giving up the chase.

Again and again

And again.

Why do they give up so often?

Burke: Are they easily distracted?

Narrator: Mother cheetahs usually have three

Or four major distractions, their cubs.

Cheetah cubs are at great risk from lions, leopards,

And hyenas, especially when their mothers

Leave them to hunt.

Galante: A mother cheetah is particularly stressed,

Because only 40% of cubs make it to adulthood

In the kalahari and 5% percent in the sahara.

Daly: So all cheetahs abandoning the hunt

Because of having to be alert

And be on the look-out for predators

In order for them to keep their cubs safe?

Narrator: There is one problem with this idea,

Male cheetahs also give up the chase

And they don't play a role in caring for cubs.

So could it instead be physical stress,

That causes the cheetahs to burn out.

In an effort to avoid competition

From other predators,

Cheetahs hunt during the daytime

When other big cats are sleeping.

However, this can make hunting even more exhausting.

Burke: One of the downsides of hunting in the middle

Of the day is that it's also the hottest part of the day.

Once they decide to give chase,

They only have a limited amount of time

Before their bodies start to overheat.

Narrator: In polokwane, south africa

Dr. Robyn hetem, who studies cheetahs living in sanctuaries,

Put the overheating theory to the test

Using the latest heat monitoring technology.

Hetem: We were able to attach small biologging devices

Which could remotely assess body temperature

Off free-living cheetah in real hunting experiences.

♪

Narrator: So what did she discover?

Hetem: Surprisingly we found no temperature increase

When cheetah were hunting.

The cat is able to dissipate that heat effectively

Through evaporative cooling.

Narrator: Overheating is ruled out,

So what is causing cheetahs to give up the chase?

Professor alan wilson from the royal veterinary college

In the uk analyzes the footage,

He reveals that its he direction of the chase

That can foil cheetahs.

Hunts don't happen in a straight line,

It involves turning, it involves ducking and diving

As the antelope tries to escape and the cheetah tries

To follow those movements.

Very rarely do cheetahs even approach half their top speed

Hunting, it's not about absolute speed,

It's about maneuverability.

Narrator: And it's the zig-zagging course

That prey, such as antelope, go on

That sometimes gives them the upper hand.

Wilson: This is because the antelope defines the hunt

By setting course that is challenging

For the cheetah to follow.

And that is where the antelope gains it's advantage.

Narrator: Meaning cheetahs don't just need speed,

They need agility to get a meal.

When a cheetah is hunting prey, it's the first one

To make a mistake that loses.

The cheetah makes a mistake, the prey is going to win.

Narrator: So, while cheetahs remain the fastest land animals

On the planet, sometimes even they have to admit defeat.

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

Captions paid for by discovery communications