01x04 - Freshwater

[bunniefuu]

[majestic music]

[turtle whining]

[whimsical music]

[David] Deep underground,

Amazon turtle hatchlings
are waiting for rain.

[thunders]

They need just the right amount

to soften the sand
to dig themselves free.

[soft music]

Their mothers are waiting
nearby in the river.

[music]

[thunders]

Too little rain,
and they will be trapped.

Too much, and they will drown.

[music]

Life cannot exist without water,

but too much or too little
can be disastrous...

[music]

and it can change in an instant.

[music]

If they are to succeed

in spite of fresh water's
constant changes,

parents everywhere must adapt.

[music]

In the Amazon's dry season,

huge sandbanks appear.

In three months' time,

the annual rains will return

and submerge the banks once more.

Now is the giant Amazon river
turtle's opportunity

to lay eggs...

[soft music]

but she must get the timing right.

[music]

Other turtle mothers are gathering,

waiting to lay their eggs.

[music]

This is the biggest gathering
of freshwater turtles

on the planet.

[music]

The exposed banks remind the females

that now is the right time to nest.

When one finds a place that suits her,

she lays nearly a hundred eggs
a meter beneath the surface.

[music]

[dry brushing]

She has made her best guess

as to the right time to nest this year.

[music]

Now she needs the rain
to match her predictions.

[music]

Six weeks pass.

The sun has baked the sand
above the eggs

into a protective crust.

[chirping]

But the rain clouds arrive...

early.

[low-key tense music]

In two of the past five years,

early rain drowned
most of the hatchlings.

[raining]

This is not good.

[music]

As the rain falls,
the river starts to rise.

[music]

[raining]

The babies have hatched,

but they can't yet dig themselves free.

First, they must wait

while they absorb part
of their yolk sac.

[music]

The river continues to rise

and, before the eggs have all hatched,

some nests start to flood.

[music]

The sand is getting more
and more waterlogged.

[dripping]

They can't wait any longer.

[dripping]

[muffled shifting]

Three days after hatching,

the baby turtles see sunlight
for the first time.

[soft music]

But their mother's job is not done yet.

Waiting offshore, they call.

[low-pitched turtle call]

It seems as if the mothers'
song guides the hatchlings

to safety amongst the adults.

[music]

[chirping]

[music]

This year, many mothers
got their timing right...

...and over two million
hatchlings emerge.

[soft music]

[soft pattering]

[low-pitched turtle call]

As the hatchlings join
their mothers in the water

they add their voices to the chorus.

[low-pitched turtle call]

When freshwater flows are reliable,

parents are able to give their young

an excellent start in life.

[music]

But even when water levels are stable,

there may still be dangers
for young animals.

[monkey vocalizes]

[birds chirping]

In a steaming swamp in South Carolina,

hungry mouths gather...

around the perfect home

for a family of swamp canaries.

[birds chirping]

These parents have chosen
an excellent site

a slim tree, surrounded by water.

[music]

Nests like these are difficult to reach

from land, water, or air

for anything but a small bird...

[birds chirping]

Useful to protect baby chicks.

[birds chirping]

[soft music] [birds chirping]

Up to seven of them in a nest.

As well as feeding their young,

the parents keep their nests clean

by removing the chicks' droppings...

[music]

in poo bags.

[music]

[birds chirping]

[music]

Caring for as many chicks
as this is a two bird job.

[birds chirping]

[music]

[birds chirping]

[music]

A small nest may be safe,

but chicks can quickly
grow too big for it.

Leaving their tower will require them

to take their first flight...

but the moat around their castle

is now a major obstacle.

[tense music]

Predators lurk,
waiting for an easy meal.

[water moving slowly]

It is at least ten meters
from the nearest tree.

[music]

Ready or not,

time to leave the nest.

[wings flapping]

[music]

The first hatched are the strongest,

and they lead the way.

Later hatched chicks
are smaller and weaker.

[curious music]

[water pops]

The water is no place for a chick

but there's nothing his parents can do.

[water popping]

Although he's made it to the tree,

he's still in danger.

But now his parents can help...

[birds chirping]

...using rewards.

[birds chirping]

[curious music]

Bit by bit, they coax him higher.

[music]

Just a few more steps.

[music]

There, now.

He's out of immediate danger.

[music]

His parents coax the rest of the chicks

to safe hiding places
all over the swamp.

They will continue to feed their chicks

for five more weeks.

[music]

[David] Large expanses of fresh water

can be dangerous.

Small pools like this one,

away from the main Amazon river,

are safer for young animals.

[birds chirping]

The center is open and clear,

and the edges provide
plenty of hiding places

excellent for a family of cichlids,

provided that the parents
can work together.

A carefully chosen rock
in the center of the pool

camouflages the eggs.

They are starting to hatch.

[whimsical music]

Wriggling tails, however,
could attract attention.

But the mother gently picks them up

and puts them out of sight,
under a leaf.

Father does his best to help.

[music]

But he's getting in her way.

[music]

While mother is collecting more eggs...

[music]

she turns around to find that
her partner is at it again.

Caught in the act.

[music]

She clearly wants
to finish the job herself.

Working alone,

mother gets every last
wriggler tucked away safely.

[music]

But she will need father's help

when their wrigglers become swimmers.

Now, both parents must guide
their offspring

to the edge of the pool,
where there's more cover.

[music]

First step

navigate through a shoal of grim bata.

It's a job that requires two adults...

[lively music]

...so now it's father's chance to help.

[music]

They've made it, all fry accounted for.

But they've hit yet another road block.

[low-key suspense music]

Cichlids are very territorial,

and this family has drifted
into someone else's patch.

[music]

Their neighbor has turned dark,

showing that he really wants them gone.

[music]

Worse, he might also be hungry

and regard the fry as a welcome snack.

[intense music]

[music]

By coordinating their attack...

they win the fight.

[soft music]

Finally united,

they can continue to their new home.

It's exactly what they need.

The fry can practice swimming
in the spring's bubbles,

and there are plenty of hiding places.

[soft music]

Together, the cichlids
have made the most

of all this pool has to offer
their young family.

[David] [Where freshwater is rare,

parents have fewer options.

The Namibian desert.

Here, there is very little
water for miles around,

except in the breast feathers
of this Namaqua sandgrouse.

They are specially adapted to absorb up

to 25 milliliters of water,

and that enables his family to nest

in remote corners of the desert.

[music]

But the chicks must drink
at least once every day

to survive,

so father must fetch some for them.

[music]

Almost 20 miles from their nest,

a thin strip of green
indicates standing water.

[music]

The male sandgrouse flies
to this waterhole every day.

Here, he joins a flock
of other thirsty sandgrouse.

But they all know better than
to head straight to the water.

[flapping wings]

First, they settle at a safe distance.

[music]

Hidden among the rocks,

the flock's many eyes
scanned for lurking threats...

Because, when freshwater is rare,

it can be used by some as a trap.

[music]

A lanner falcon,

a booted eagle,

and an African hawk eagle

have all taken up positions
around the waterhole.

[music]

[birds chirping]

Despite the threats,

some sandgrouse decide
to take their chance.

Parents are vulnerable at the water.

They need at least
five minutes in a pond

to saturate their feathers.
The more cautious birds

wait to see what happens
to the first group.

[birds chirping]

[intense music] [loudly chirping]

The lanner picks a target.

[music]

She misses.

[birds chirping]

The booted eagle sees her chance.

[birds chirping]

Together, they keep
the flock in the air,

a spectacle visible from all around.

[birds chirping loudly]

Especially to a male
judging when it's safe

to collect water for his chicks.

[birds chirping loudly]

Birds of prey seldom stop...

[birds chirping loudly]

...until they make a catch.

[birds chirping loudly]

Even now, going alone could be fatal.

He must stick with the group.

[music]

There's no one left in the air.

[music]

If the predators are
concentrating on eating,

now could be
the sandgrouse's opportunity.

[flapping wings]

But they have overlooked someone.

[music]

The hawk eagle.

[music]

To soak their feathers,

parents must wade deeper into the pool.

[music]

In their desperation for water,

no one notices the eagle's approach.

[flapping wings]

[suspense music]

[flapping wings]

The father must hold his nerve.

He has not yet collected enough water.

[flapping wings]

[music]

[tense music slowly]

Missed.

[soft music]

This father wings his way home

breast feathers fully loaded with water.

He will have to repeat
this journey every day

for the next eight weeks,

until his chicks are ready

to visit the waterhole for themselves.

[music]

For now, they can enjoy
a good long drink.

[music] [birds chirping]

The water's presence here

has enabled these parents to succeed.

[soft waves crashing]

[David] In the Caribbean,
five miles upstream,

lies a near-perfect nursery pool.

Food here is plentiful,

and the water tumbling
from the falls above

keeps it clear and oxygenated.

[music]

After five months at sea,

a tree tree goby has climbed 300 meters

to reach this pool and start a family.

His partner is ready to lay her eggs.

[music]

Pebbles arranged in the right way

will alter the flow of the current,

creating good conditions for eggs.

[music]

His activities attract attention.

[music]

Rival males are eager
to take over his nest.

[music]

He'll have to fight
if he's to become a father.

[music]

Good riddance.

But one thing he can't
fight is the weather.

[thunders]

A once in a lifetime storm is brewing.

[thunders]

[water flowing]

[howling wind]

[slow drip]

[raining]

[strong waterfall sound]

Below the fall, the increase in water

has turned the gentle flow
into a whirlpool.

[intense music]

The torrent has flushed him
miles back downstream...

but he still has a chance
to become a father,

if he can manage to climb once again

to his nursery pool.

He hasn't done anything like this

since he was a young fish,

and it shows.

[music]

He's a lot bulkier than
when he was younger.

Climbing 300 meters again

won't be easy in his current condition.

Juveniles with boundless
energy dart past him.

[music]

Other adults try...

and fail.

He pushes on,

but the closer he gets to his pool,

the stronger the current.

[strong waterfall]

[music]

With one final push...

he makes it.

[soft music]

But the pool is unrecognizable.

The storm has scattered

all his carefully selected pebbles...

...so he starts work
to create another nursery.

[music]

If he is to become a parent, however,

he will need stability.

When freshwater is not stable,

parents must quickly adapt

to ensure a future for their young.

[chirping]

[David] Thailand.

These still waters should
offer a secure foundation

for the family of a lily trotter.

Long toes spread his weight
across the lily pads

as he searches for insects
amongst the greenery.

But he also has a special
and urgent job.

[curious music]

He's building a floating nest.

[music]

A messy pile of pond weeds
will have to do.

He must hurry back to his egg.

[music]

He misguidedly built his first nest

in the busiest part of the lake.

Boats come so close that
his egg risks being crushed.

[music]

He has decided to move
to a quieter neighborhood.

[music]

Building a new nest was easy.

[music]

Moving an egg without hands
is significantly harder.

[music]

Other lily trotters carry
their eggs with their beaks.

[music]

This one has adopted a different method,

[music]

one that takes a lot longer.

[music]

At last.

[music]

Now he must settle his egg
into this perfect new home

in his perfect new neighborhood.

But in trying to avoid one threat...

he hasn't noticed another.

Caterpillars have invaded
the lake almost overnight.

[mood music]

They don't have any predators here.

[music]

His precious chick has
hatched into devastation.

[music]

The insects that live amongst
the lilies are harder to find,

let alone catch...

[music]

and the caterpillars
are completely inedible.

[music]

His chick needs food.

Once again,

he will have to find somewhere better.

[music]

Lily trotters aren't built for this.

[music]

But walking is their only option.

The chick can't yet fly.

[music]

These are the last remaining
lilies in the lake.

[music]

It's not perfect,

but there are plenty
of insects for his chick.

[music]

Here, it can thrive.

[music]

Lily trotters are not the only parents

who must settle for less than perfect

in our changing world.

[howling wind]

[David] In East Africa,
as the climate heats,

rainfall is becoming less predictable.

This elephant matriarch
has kept her family alive

throughout two years of drought.

She's leading them to the last
flowing water she knows of,

the Ewaso Ng'iro River.

[soft music]

This is the only place for miles around

which still has any water
or food for grazing animals.

[music]

Until rain and good grazing
return elsewhere,

this is an oasis for the whole family.

[music]

[elephants trumpeting]

They haven't drunk for days.

This is a chance for a mother

to demonstrate good trunk technique.

Her calf certainly needs the tutorial.

Step one, get water into your trunk.

[suction sounds]

Step two,

get water from your trunk to your mouth.

[soft music]

Sometimes it's easier
to take a more direct route.

[music]

These days spent in the cool, calm river

are much needed relief
for the whole elephant family.

[elephants trumpeting]

[music]

[grunts]

[music]

But the elephants are not
the only travelers

seeking refuge.

[music]

[trumpets and grunts]

The elephant matriarch decides
that it's not safe enough

for trunk lessons to continue.

Wild elephants and human beings

usually avoid one another

each is too dangerous to the other.

In this drought, however,
they have no choice

but to share the river and the grass

until rain returns.

[music]

Weeks pass.

Herders and elephants
crisscross the river

in search of any grazing that remains.

So many mouths to feed
takes a toll on the land,

stripping it bare.

At last, the elephant matriarch

senses something familiar
on the horizon.

[howling wind]

Rain is falling on the distant mountains

that feed the river.

[grunts]

This should be a good sign.

But the hotter the air,
the more moisture it stores.

[thunders]

So when, after a long, hot drought,

rain finally comes,

there is much more of it.

The distant deluge runs off
the parched earth

and becomes a flash flood.

[water flowing aggressively]

[mooing]

The herds have been caught out

split apart by the sudden flood.

[mooing]

The herders have no choice but to cross

and keep their livestock together.

The elephant family
has also been caught out,

trapped on the wrong side of the river.

[music]

To follow the rain to fresh grazing,

the matriarch must find a way to cross

while keeping the youngest safe.

[water flowing aggressively]

She tests the current with her trunk,

assessing whether or not

the youngest can manage the crossing.

[grunts]

The flow seems gentle enough
on this side.

[tense music]

But the current runs swifter
near the opposite bank.

[music]

[grunts]

As the current gets faster,

the adults use their bodies
to shield the calves.

[music]

As the family enters
the swiftest part of the river

a calf loses its footing.

[baby elephant grunts]

So far, the matriarch has
kept her family together...

but now she has a decision to make

press on towards fresh grazing

or turn back to keep her calves safe.

[elephant grunts]

[elephant grunts]

She has decided.

The risks of crossing have

become greater than the pangs of hunger.

[music]

The matriarch has protected
her youngest from this flood.

But as the world gets hotter,

droughts and floods are
becoming more intense...

destabilizing life
for parents everywhere.