Original subtitles

All around the planet,

billions of animals are on the move...

making incredible journeys.

The most amazing of these are the smallest.

This series uses the latest camera technology

to follow six tiny animals on the biggest adventures of their lives...

as they travel through extraordinary landscapes...

where every little step counts.

In this episode,

a Madagascan chameleon makes the journey of her lifetime.

And a Scottish water vole faces Highland Giants to find a new home.

The greatest adventures are the smallest.

Kirindy Forest, Madagascar.

This tiny chameleon is a few minutes old.

Half the size of a matchstick,

she has spent seven months underground,

developing inside her egg.

And now her own eggs are already growing inside her.

She's starting a journey to find a male.

These chameleons only live for a matter of months.

Her instincts drive her to climb.

Built for the ascent,

her feet can swivel...

helping her cling to cracks.

She heaves her way upwards.

The climb is 150 times her body length,

like a human scaling the Empire State Building.

Five metres up,

she's in a very different world.

A dense network of branches that give shade

and create aerial highways.

She's hungry.

She has never eaten before,

but knows food when she sees it.

Flies.

They have split-second reflexes...

but she's born with the skills of an assassin.

Her eyes search almost 360 degrees.

A target.

Both eyes lock on with binocular vision.

She fires her lightning-fast tongue.

It's twice the length of her body and as sticky as honey.

She catches up to 100 flies a day.

It takes two weeks to double in size.

The fading light and decreasing accuracy

is her cue to get some sleep.

Being light, she can reach places where most predators can't.

The thinnest branches are the safest.

Her pincer-like feet clamp onto the branch.

It's like sleeping on a tightrope.

A cat-eyed tree snake.

A metre long.

Over ten times bigger than she is.

It's still light enough to reach her.

Deep in slumber,

the chameleon is at her most vulnerable.

The snake's approach causes tiny vibrations along the branch,

that the chameleon can sense even when asleep.

And when the snake is too close...

they wake her up.

All she can do...

is let go.

Her radical move is a deliberate escape strategy.

But it has put her right back on the dangerous forest floor

in the middle of the night.

6,000 miles away...

the Cairngorms of Scotland.

Home to one of Britain's shyest animals...

a water vole.

This female is three months old

and small enough to fit in the palm of a human hand.

She is busy preparing her small territory by digging burrows,

ready to raise a family.

She must eat two thirds of her body weight every day

to stay in prime condition.

There's just a few weeks left to mate and raise pups...

before the first signs of winter.

To attract a suitor,

she strategically leaves droppings around her territory.

Today, they've got some attention.

A vole's worst nightmare.

An invasive American mink.

Its ultrasonic hearing can detect the slightest squeak.

SQUEAKS To a water vole,

its odour is a trigger to run.

Just one mink could wipe out every vole in this glen

in just a few weeks.

She's lost her riverbank home.

She must now travel into the unknown to find a new territory

in which to have her first pups.

Two miles into the glen...

she's alone, homeless and exhausted.

She needs a place to rest.

A burrow.

She could make it her new home.

It's occupied.

A pregnant water vole.

This is her burrow.

And she will fight to the death to defend it.

Being less experienced,

the best option is to flee.

But the path ahead...

is blocked.

In Madagascar,

with her biological clock rapidly ticking away,

the chameleon is searching for a way into the trees.

She's unaware of the predators that lurk in the dark.

A way back up.

Things are not as they seem.

As she travels, her cover disappears.

She's on a dirt track,

cut through the forest by humans.

Drawn towards a tree trunk,

she hauls herself upwards with every ounce of energy she has left.

Finally, she can get back to sleep.

Dawn reveals a harsh reality.

Once there were trees all the way to the horizon.

Now there is nothing.

It's a long way back.

Finally in the safety of a tree.

But she's facing another problem.

Being shaken off is the last thing she needs.

Red-fronted lemurs.

Feeding on the fruit in this neem tree,

they've created a sticky mess.

A magnet for flies.

A chance to get her energy back

before she continues her journey to find a mate.

The vole's search for a new home

has taken her three miles into a glen.

Ahead of her lies water.

She's spent her entire life around streams.

But with poor eyesight,

she has misjudged how far it is to the other side.

This loch...

is vast.

In the cold waters beneath her...

monsters lurk.

Giant pike,

four times her size, could swallow her whole...

if she doesn't drown first.

She's never swum more than a few metres from land before.

The further she swims from shore,

the more likely she will be detected.

Once a pike senses ripples...

most prey don't stand a chance.

But this water vole has made it to the other side.

For now, she's safe.

Running water.

It's the sound of home.

If she follows it, she might find the habitat that she's looking for.

The higher she climbs,

the rockier it becomes.

200 metres up,

there's trouble.

A golden eagle.

30 times bigger than a water vole.

With vision five times more powerful than a human,

it could spot a vole from over a mile away.

She will have to sleep here tonight.

In Madagascar,

four months have passed,

and the chameleon has reached a pivotal moment in her short life.

She has undergone the most extraordinary transformation.

She has become an adult.

Now as long as a human finger,

her skin is a kaleidoscope of colour...

created by special light-reflecting nanocrystals

in her skin cells.

A chameleon's colour is primarily used for communication,

and it changes with her mood.

Her most important signal is a crimson spot...

indicating that she is ready to mate.

Her eggs are fully grown and visible through her skin.

Now she needs to find a male to fertilise them.

She needs to secure an area to show off her colours.

But every female of her species is on the same biological clock...

all vying for the attention of a male.

Already, she has competition.

Females can't risk damage to their delicate eggs.

They rarely make contact.

Instead they rely on elaborate warning displays.

She attacks from below.

Having forced her rival away...

she's claimed this area as her own.

She can now dazzle her colours.

She's attracted a male.

There's two.

They must prove their worth.

They are twice the size of her.

Built for combat.

The bigger the nose horn, the more attractive the male.

And the taller the head crest, the more powerful the bite.

These two gladiators are evenly matched.

She monitors every movement from a safe distance.

The most dominant male will pass on the strongest genes.

They must fight it out to win her favour.

Unlike females,

they don't hold back.

This could be the last battle of their lives before they die.

It will only end when one backs down...

and falls.

She allows the victor to approach.

After mating, they will never see each other again.

With her eggs fertilised,

there is only one more stage of her journey to complete.

To find a safe place to lay them before her life comes to an end.

The water vole is five miles from her old river bank home.

Her search has taken her to altitude.

She's in alien territory...

but keeps climbing.

She's 700 metres up.

Before her lies a new frontier.

With the threat of the eagle,

she must move on quickly.

She's lost a lot of weight and is depleted of minerals.

She'll need more than just grass to get her strength back.

Red deer.

They may provide just what she needs.

An old stag's antler, packed with minerals.

100 times more calcium than milk.

A few nibbles is all she needs.

This is prime water vole habitat.

Further into the glen, there's a burrow.

There is something here.

It's just a harmless toad taking shelter.

With no sign of a resident water vole,

she's found a new home.

If she can find a mate,

she will still have time to raise a family.

With darkness falling,

she can rest.

The chameleon is five months old...

and has reached old age.

Nearing the end of her journey,

she must find the perfect spot to lay her eggs.

She has no time to waste on an approaching male.

He's too late.

Puffing up her body and expanding her skin cells,

she turns from green to black.

A clear signal to back off.

Instinct drives her towards the forest floor.

Now a beacon of colour,

she stands out amongst the leaf litter...

and is slower,

weighed down by eight eggs,

a third of her body weight.

She needs to head away from tree roots

to a place where she can dig...

and with just the right amount of sunlight to incubate her eggs.

With every step, she could be spotted.

A giant hognose snake,

almost two metres long.

Her only defence is to rock gently...

to try to look like a leaf in the breeze.

This snake is an egg-eater.

The chameleon needs to wait for the coast to be clear

before she can start laying.

She's found the perfect spot.

Her whole short life has been about getting to this moment...

and her time has almost run out.

With her last ounce of energy,

she covers her eggs.

Her life's journey is now complete.

In her last moments,

her skin erupts with colour...

as if uttering her last words.

She's not the only one to have made such an incredible journey.

Every chameleon of her species is now dead.

All that remains are thousands of eggs

buried beneath the soil of Kirindy Forest.

Time capsules,

evolved to survive the deadly dry season...

until they hatch en masse

when the wetter weather returns in seven months' time.

Having found perfect habitat,

the water vole is scent marking the boundaries of her new territory.

But she needs to mate within the next few days

to ensure any pups survive the winter.

100 metres from the burrow,

she sniffs a distinctive odour.

A latrine.

There's a well-trodden path...

and the chopped up leftovers of a meal.

At last - a male.

The voles here have lighter coloured fur.

A sign that they have different ancestors.

But attractiveness has little to do with fur colour.

The most important thing to her is his fitness.

Crucial if her offspring are to inherit genes essential

for survival in the Highlands.

A game of chase is a good test of his stamina.

She leads him to her new burrow.

Her journey is complete.

She's found a mate and a new life

eight miles from where she was born.

Three weeks later and a new journey begins.

Motherhood.

Filming six little animals required a collaboration between TV crews

and scientists around the world.

Wow. Oh, wow. Look.

Over two years, the team filmed on five continents in order

to follow these journeys.

The most remote location was western Madagascar's Kirindy Forest,

the home of one of the most extraordinary journeys of all.

Travelling in the cyclone season,

the first challenge was getting to the forest.

But the team's journey comes to a halt when a fallen tree

blocks their only way in.

It's a long way back for help.

At least someone brought an axe.

Yeah, it looks like pretty tough going, so could be here a while.

Four hours later,

progress is slow.

With the tree finally chopped into pieces,

they must still drag it out the way.

There are several miles to go yet.

We've just arrived after 13 hours of driving.

I'm amazed that the car's actually made it through the amount of water.

We've no electricity and it's absolutely torrential rain.

With a break in the rain,

the team can finally start searching for the chameleons.

One of the scientists studying the forest's chameleons

is Ludo Raoelina.

During the day, it's so difficult to find them.

It's better to search at night.

Finding a reptile no bigger than a human finger is challenging.

Luckily, chameleons turn pale at night and sleep

at the end of branches, making them easier to find by spotlighting.

Cameras at the ready,

things finally seem to be going well for the team.

whoa!

Did you see that?

We were just about to start filming and just, yeah.

Just torrential. THUNDER RUMBLES

Just so wet.

You could literally wring me out.

Literally wring me out.

Filming has to stop.

After several days, the storm passes,

but the fleeting life cycle of the Kirindy chameleons

is moving fast.

Ludo is joined by Christopher Raxworthy,

who has been studying chameleons in Kirindy for decades.

I have been fascinated with chameleons

since I was a young boy and Madagascar was always

a special place.

If you want to see these chameleons, Kirindy is the place to come to.

Kirindy isn't just a haven for chameleons.

This forest is incredible.

Loving all of the amazing animals

that we're finding in the forest.

We've seen sifakas and brown lemurs and loads of beautiful birds,

beautiful butterflies.

Some of the wildlife has taken a shine to one member of the team.

So, Owen and I are currently in a tornado of flies.

You having fun, Owen? No.

Why are you not having fun? OWEN COUGHS

Cos the flies like me too much.

Despite the challenges, the team are able to document every element

of this extraordinary life cycle

for the very first time.

But they may also be filming this for the very last time.

These chameleons hatch, grow up,

and die during one season.

This unique life cycle has left them very vulnerable.

It seems like a very risky strategy

to actually put literally all your eggs in one basket.

You could imagine if the eggs didn't hatch,

then there's no backup generations to keep the population going.

With their lives so intimately in sync with the seasons,

a shift in the climate could be devastating.

The rainy season now starts in Madagascar perhaps as late as

two months later than when I first started working in Madagascar.

And it's not just the climate that is changing.

The environmental pressures on Kirindy have increased

over the last 20 or 30 years.

And so the great news is we have a lot more forest now

which is protected with inside reserves, but we also can tell

from satellite images and from personal experience that we can

still see ongoing declines in terms of the total forest area.

Over the last 70 years,

half of Madagascar's forests have been destroyed, putting much

of its unique wildlife, including the chameleons,

at risk of extinction.

Sadly, I have seen forests that I worked in and love

being degraded and cleared,

and so that's a very painful experience to sometimes see

that kind of biodiversity loss.

Ludo and many other local scientists are determined

to preserve the remaining wildlife.

The work of dedicated conservationists around the world

is helping the tiny animals featured in this series

to continue their journeys for many generations to come.