All language subtitles for BBC.Life.In.The.Undergrowth.2005.Part1.DualAudio.DVDRip.XviD-EaGlE

An eye - from another world.

A smell-detector -
investigating the path ahead.

We don't often see a snail that way.

And that's because we've only recently
had the tiny lenses

and electronic cameras that we need to
explore this miniature world.

But when we meet
its inhabitants face to face,

we suddenly realize that
their behavior can be just as meaningful

to us as the behavior of many animals.
More our own size.

Look at this, for example.

It's an earwig.

Yes...

But it's also a female and a mother -

and, like so many mothers,
she's guarding her young.

These two ants are not quite sure
whether they like one another.

Stroking antennae is the equivalent
of a cautious chat over the garden fence.

When big animals go courting,

they show off-
and so do damselflies.

Courtship signals for a male wolf
spider are rather more frantic

because if his female doesn't
understand why he's approaching her,

she'll eat him.

This ant is a farmer -
and these aphids the cows which it milks

for a drink of Honey-dew every day.

Other ants are eternally on the march.

Powerfully armed soldiers guard
the flanks of their column as they travel,

protecting the workers
who are carrying their helpless Young.

When it comes to craftsmanship,

few can beat this wasp using mud
to construct an elegant jar

in which to store her eggs.

Mud is also used by termites.

They build tower blocks that,
in proportion to their size,

are taller than New York sky-scrapers.

These two worlds - ours and theirs -

influence one another to
an extraordinary degree.

If we and the rest of the back-boned
animals were to disappear overnight,

the rest of the world would get
on pretty well.

But if they were to disappear,
the land's ecosystems would collapse.

For the fact is,
they were the pioneers,

the first animals of any kind to
colonize the Lands of the earth.

To tell their story,

we must go back to a time when
the world was a very different place.

Some four hundred million years ago,

the lands of Planet Earth
were totally without life.

They were bare, naked rock,
roasted by sun during the day,

freezing cold at night and swept
by terrible storms.

But in the waters of the world,
conditions were much more stable.

Life had begun there some
two thousand million years earlier still.

For a long time it
remained microscopic.

But eventually larger animals appeared

- jellyfish, corals, starfish and snails,

and animals with segmented bodies.

All needed food.

Many would have eaten unguarded eggs,
given the chance.

And then,
around four hundred million years ago,

some enterprising creatures found it
safer to lay their eggs out of the sea,

up on a beach.

They still do.

Every spring,
on a few special nights along

the Atlantic coast of North America,

thousands of horseshoe crabs emerge
from the sea

And here, in the wet sand, they spawn.

They may only stay
for a few minutes or hours,

but animals like these may well
have been the first

of any kind to leave the sea
and venture on to land.

Although these creatures spend
virtually all their lives at sea,

they can survive surprisingly
well on land.

It's almost as
if they were pre-adapted.

They have shells -
external skeletons -

and that means that their legs
are rigid and jointed.

And at the back they have a series
of plates called book-lungs

which extract oxygen from sea water,
but can also do the same thing

if they're kept reasonably moist,
from the air.

So creatures like this can in fact,
spend about a week on land.

And it only requires
minimal modifications

to enable them to
live up there permanently.

It was difficult to abandon the sea
altogether until the land became green,

but eventually, it did.

Simple plants - algae and then mosses
and liverworts -

began to advance over the mud
and rock to clothe the earth.

And into these first green tangles
came animals looking for food.

Some had armor,

for that in the sea had protected them
from their enemies.

Now it would help them
conserve moisture.

They were the ancestors of
today's millipedes.

Small holes had developed along
the underside of their bodies

that led to internal tubes with which
they could absorb oxygen from the air.

Their rigid jointed legs, however,

were largely unchanged
and worked very well on land -

even without the support of water.

Battering-ram heads enabled them

to bulldoze their way
through the vegetation

to collect the rotting plants
on which they fed.

They grew big, increasing the number
of segments in their bodies.

Some had over three hundred -

each with two pairs of legs.

Some that didn't curl up

reinforced their armor
with plates along their backs.

Crustaceans like shrimps came too.

They were the ancestors of woodlice.

So today, there is a huge
and varied population of animals,

living on the land with bodies
that are little different

from those of their ancestors
who lived in the sea so long ago.

And they are extraordinarily
successful -

some are the most numerous
of all land-living species.

But we seldom see them.

This pin will give you
an idea of why.

They are tiny.

This minute little creature
is a springtail.

It's less than half a millimeter long -
the size of a full stop.

In one square meter of soil,
there maybe over ten thousand of them.

Drying out is a very real danger
for them

and some waterproof
themselves regularly with a droplet

of special grooming fluid.

You might even say they have
turned bathing into an art form.

They even have two inflatable tubes
that enable them

to get to those hard-to-reach laces.

To help them get around through
the leaf litter,

these springtails -
as their name suggests,

have a rather novel way of jumping.

They have a tiny two-pronged
lever beneath their abdomen.

One small flick from it can catapult
them six inches -

some fifteen centimeters - into the air.

It's the equivalent of a human being
jumping over the Eiffel Tower.

And if they happen to
land upside down - well,

they have a special way
of righting themselves.

They use their grooming-fluid dispenser
to stick onto the ground

so that they can pull themselves back
onto their feet.

So the foundations were laid for

the ecosystems that now flourish
on earth -

and on which we ourselves depend.

It has to be said, however,

that sometimes some of us regard
a few of these pioneers

more as our enemies than our friends.

Many of the mollusks
in the sea developed shells

to protect themselves from predators.

But on land, those shells served just

as well to keep the occupant nice
and moist.

So without any major
change to their anatomy,

mollusks were able to
creep up out of the water

and graze in the forests
of algae and mosses

that were then spreading over
the land.

And given the right conditions
they still do.

With rain and the coming of night,
a secret army comes out of hiding.

These are the conditions
they like best.

Dark - and - best of all - wet!

Gliding along a carpet
of slime works

just as well on land
as it does under water.

And a rasping tongue scrapes
algae off rocks wherever they are.

In times of drought,

snails may be unable to move around
for months on end,

so when conditions are right,
they eagerly set off to find food.

Their upper pair of tentacles carry
those eyes with which they look around.

The lower ones smell what's beneath.

They breathe by means of a small pouch
on the right hand side of their body,

just within the shell which,
because it's permanently moist,

is able to absorb oxygen.

This is what they're seeking -
a succulent green leaf.

No time to be lost.

Dawn will bring a change in conditions.

So they have to return
to their shelters

and clamp down their shells once more
so that they retain their moisture.

The ancient forests were colonized
by all kinds of plant-eaters long

before there were any frogs or lizards,
birds or insect-eating mammals.

But there were, nonetheless,

hunters prowling
through the vegetation.

This was one of the first.

Fossils very like
it have been found in rocks

that are five hundred
and forty million years old.

This is a velvet worm.

It too has scarcely changed
since it lived in the sea,

and today it's only found in wet,
humid forests.

It usually hunts at night,

but infra-red cameras
can reveal it in action.

Soft stumpy legs enable it to move
in total silence

and it finds its way
with long sensitive feelers.

It's a master of stealth.

This cricket has huge eyes,

but its very difficult to see
what's going on around it.

Although the velvet worm has fangs,
it will attack its prey,

when it finds it,
with a very special weapon.

Anxiously, the cricket probes around

in the darkness with its long antennae.

The velvet worm will only know
if it's found its prey

when it touches it.

So when it does,
it has to react immediately.

There!

And the cricket is trapped.

A slow motion camera shows
the remarkable way

in which the velvet worm attacks.

Two nozzles beneath its feelers
squirt twin streams of glue.

The more the cricket struggles,
the more it becomes entangled.

With the prey immobilized,

the velvet worm reclaims its glue
by eating it

and then it starts on the cricket.

There were other hunters too
in the ancient forests -

relatives of the horseshoe crabs
and they were even more formidable.

This is a whip-spider.

Like its ancestors,
it has a hard external skeleton.

Two of its limbs have been turned
into highly mobile sensitive feelers.

It uses them to probe around delicately
both in front and behind.

Any prey within a foot of it will be
immediately detected.

It's extremely territorial
and it has no hesitation

in attacking one of its own kind.

The width of its claws
is a good indicator of strength

and a smaller animal
will quickly back down.

But these two are equally matched
- and they will fight.

The loser retreats.

But even whip spiders were not

the most formidable hunters
in these forests.

There were others with an even
more venomous weaponry.

This centipede has powerful jaws,
poison fangs and is very, very fast.

It's a very good hunter,

but it's only half as long
as my little finger.

There are centipedes in the world,
however, that are as big as my fore-arm.

This is one of these alarming giants.

It's over thirteen inches -
35 centimeters -

long and with the muscular strength
of a small snake.

And the poison in its black-tipped
fangs is lethal.

It hunts in the dark,
bat-haunted caves of Venezuela.

Like the whip spider and the velvet worm,

it uses its antennae to feel
for its victims.

The beetles that swarm
on the rocky floor

of the cave are of no interest to it.

It's after bigger prey.

And it knows it can find
that by climbing.

Its many legs give it a secure hold
on the vertical rocks.

It's heading for the ceiling.

Now, in the darkness,
it can sense bats flying past it.

Holding on with its hind legs,
it reaches out into their flight path

and almost immediately it has one.

An injection of venom
from its fangs kills

the bat almost instantaneously.

It will take it an hour or so,
but it will eat all the bat's flesh.

So all these animals,
having left the sea,

solved the problems of moving around
and breathing air -

in their own differing ways.

But there was another difficulty.
Mating.

In the sea, animals need only release
their eggs and sperm

and the water mixed the two together.

On dry land, that couldn't happen -

even for the most moisture-loving
of creatures.

An individual slug carries both male
and female organs,

but even then, that was of no help.

Each had to both give and receive.

Somehow or other,
pairs of individuals had to get together.

And the ways they have evolved in
which to do so are quite extraordinary.

Indeed, some of them are almost
beyond imagining.

The leopard slug, you might think,
has the simplest of habits.

Maybe.
But not when it comes to mating.

When an individual
is looking for a partner,

it gives its trail of slime a special
taste that advertises the fact.

Another, if it feels the same way,

will detect the invitation
and start to follow.

The pursuer, to confirm
that it's there and ready to mate,

gives the pursued a nibble.

The leader heads upwards.
An overhang is what's needed.

The underside of a branch
will do very nicely.

The two start to circle one another more
and more closely until they entwine.

For an hour or so they continue
to wind themselves around one another.

Then suddenly the pair release
their hold on the branch

and start to slide downwards
on a rope of mucus.

Now in midair, they move to
the next stage in their pairing.

Each exerts its male organ
from just behind its head.

These grow longer and longer.

Then they too begin to entwine.

They fan out to form a translucent
flower-like globe.

And now at last, sperm passes
from one slug to the other.

The transfer is complete.
Each has been fertilized.

Finally, their strange balletic
relationship comes to an end

- with a bump.

A millipede, unlike a slug,
is either a male or a female.

In southern Africa,
where there are many different species,

both sexes spend the inter
in hibernation,

curled up in the leaf litter
or beneath the bark.

As the temperatures rise
with the coming of spring,

they all unwind themselves
and set off to look for a mate.

Finding one in the tangled
undergrowth is not easy.

But this male forest millipede knows

that he can increase his chances
if he heads upwards into the trees.

Leaving the safety of the undergrowth
may seem a risky thing to do,

but these millipedes secrete a poison
from pores in their armor

and their conspicuous red

and black colors warn predators
to leave them alone.

They emerge in thousands.

Surprisingly perhaps, a male,
when he does find a female,

is not met with a friendly greeting.
Quite the reverse. She coils up.

This is her way of sorting out
the men from the boys.

Only the strongest
and fittest male will have

the strength to force her coils apart.

To help him do so,
he has white suction pads

on the bottom of his feet
which give him a good grip.

Eventually,
she relaxes and he lifts her up

so that he can extend
two specially modified legs

with which he inseminates her.

Once inserted,
these legs swell so that the partners

become fastened together.

And that's important,

because it will take him a couple
of hours to transfer his sperm.

But there are lots of males around,

and before long, another one turns up.

The new arrival checks out the pair
with his antennae.

If they're not tightly bound together
he may have a chance of taking over.

He pushes between them,
levering them apart.

Gradually he manages
to unzip their legs.

The first male's white mating legs
are dragged out.

He's been defeated.

It will be the second,
stronger male who fertilizes her eggs.

So mating on land isn't as random
as it had been for so many in the sea.

Now it's selective.

But brute force isn't the only basis
on which to select.

A female springtail is bigger
than a male and she prefers a partner

who can give her
a sustained head-to-head push.

Other males are eager
to try their luck -

but butting her sides won't
get them anywhere.

She seems unimpressed
by any of them,

But one is determined
to stay as her dance partner.

She simply can't get rid of him.

He confidently signals victory
with a couple of fancy twirls.

Then he deposits a droplet
of sperm on to the leaf -

and she graciously takes it on board.

One group of colonists were
of particular importance,

for they changed the nature of the soil
and thus made it possible

for new kinds of plants
and animals to evolve.

They outweigh all other animals
in any given area of the forest.

A single hectare may be home
to eight million of them.

They spend nearly
all their time below ground.

Worms.
They eat their way through the earth,

extracting edible vegetable material
and making it suitable for plants.

And at night,

they come to the surface
and collect dead leaves.

They also take the opportunity
to call on their neighbors,

poking their heads
into next door burrows.

They're looking for partners.

Like slugs, they're hermaphrodite,

each individual both male and female.

They mate by lying
alongside one another.

Two narrow grooves
form between their two bodies.

These are the conduits that carries
sperm from one partner to the other.

Their bodies slowly pulse as sperm
travels along the space between them.

But the process is a long one
and it may be three hours

or so before they separate,
each carrying the other's sperm.

Like so many of the inhabitants
of the undergrowth,

earthworms can only live
in a Moist environment.

But they are found in soils
of every continent except Antarctica.

This small valley in southern
Australia is home to one of the rarest

and the most extraordinary
of all earthworms.

And I know they're around
because I can hear them.

Those gurgling noises,
believe it or not,

are being made by giant earthworms
Megascolides australis

as they squelch along
their water-filled burrows.

The vibrations of my footsteps are
enough to stir them into activity.

They never come to the surface.

But in places where
there's been a small landslip,

you can sometimes find their burrows.

They are over an inch in diameter.

And in them, if you're very lucky,
you may occasionally find one of these.

This is one of their egg cocoons -
and it's enormous.

If I hold it up against the light,

I can see the young worm inside,
wriggling.

It will take a year
for this to develop

and when the young one finally
does break free,

it's already twenty centimeters long.

Huge!

It will take a further
five years to reach full size -

and become this remarkable creature.

So the question is,
how long is a giant earthworm?

Well, it's not an easy question
to answer.

The fact of the matter is

they are rather delicate creatures
and they break.

If I were so unfeeling
as to try and stretch it,

well I guess it might stretch
to a couple of meters -

almost six feet long.

How long they live?

Well, some say up to twenty years,
but we really don't know.

And we certainly don't know
how they manage to mate deep underground

as they squelch their way through
their lonely tunnels.

The land may have been
a safe place for eggs

when horseshoe crabs first laid
theirs up on the beach,

but as new kinds of
animals appeared so it

became increasingly important
for animals to protect their eggs.

Most creatures just hid them,
but a few now actively defend them.

The builder of this circular mud wall,

in the Central American
rain forest is one.

During the day, he conceals himself.

But when night comes he emerges
to inspect his collection of eggs.

His body is smaller
than a grain of wheat.

He's a relative of the spiders -
a harvestman.

His eggs - up to a hundred of them -

are half buried in the floor of his nest

and he regularly inspects
each one of them.

If it has a fungus on it,
he carefully cleans it

before putting it back
into its moist bed.

He also continually repairs
and improves his nest,

for females will only call on those
who have well built and well-kept ones.

Some males, however,
follow a different policy.

They don't bother to build
a nest for themselves.

They try to take over an existing one.

A nest-holder has to leave sometimes,

to feed and that gives
an intruder his chance.

But the owner
is back almost immediately.

And they fight -

trying to bite one another
in the weakest point of their armor -

the joints of the legs.

The intruder retreats -
and the nest owner checks his eggs.

No damage done.

And then another, more welcome,
visitor arrives.

This is a female.

She is bigger than he is
and she's touring all the nests

in the neighborhood to choose
the one where her eggs

will be best cared for.

She seems to approve of the standard
of his house-keeping.

So now,
face-to-face through the tangle of legs,

she mates with him.

He has a rod with
which he injects his sperm.

He withdraws and she's been fertilized.

Half an hour later she lowers
her white tubular ovipositor,

feeling for a suitable place
for her egg.

She thrusts the egg
into the floor of the nest

and then covers it
with a thin blanket of mud.

She leaves.
He will now tend and guard the egg

with the rest of his collection
for the month that it will take to hatch.

His nest is clearly one of the best
in the neighborhood,

for throughout the night,
a succession of females call on him.

But not all have come to lay.

Life is not that simple.

This one starts, as usual,
with a routine inspection and then,

without more ado, she mates.

He waits for her to produce a new egg.

But nothing appears.

He constantly checks the nest floor
with his feelers -

but there are no signs of a new egg.

And then she grabs one
from his collection -

she wants to eat one.

She grabs again.

He bites her leg joints
and tries to pull her away.

She's had enough.
And he has rescued his egg.

He checks it over,

cleans it with great care
and then takes it away to rebury it.

A month after the eggs were laid,
his young begin to emerge.

The skins from which they hatched
provide them with their first meal.

He will now guard his young
for a couple of days

until they leave the nest.

Excellently adapted though harvestmen
are to a life on land,

they cannot survive for very long away
from this damp undergrowth.

In fact, most of the direct descendants
of those early colonists

that came from the sea,

are still trapped
in a world of moisture.

Those with no external skeletons
are always

in imminent danger
of death by drought.

Even those with exo-skeletons
are not safe,

for most have armor
that is not totally water-tight

and will eventually dry out

and die if they leave the dank shelter
of the undergrowth.

But beyond the reach of the forests,

in the center of continents
where little or no rain falls,

there is a very different territory -
empty and hostile.

Here there is little shelter
from the scorching sun.

Temperatures rise above seventy
degrees centigrade. -

and there may be no rain whatsoever
for years on end.

Deserts, like this one
in the south-west of the United States,

represented the ultimate challenge
for those ancient creatures,

whose ancestors first left the sea.

Here there's virtually no water at all.

And yet those early creatures,

the very first to walk on land,
reached even here.

And they're still around.

In order to survive
the ferocious heat of the day,

they take refuge
in little burrows like this,

which go quite a long way down
into the ground.

But I can use
this special optical probe

to see whether anyone is at home.

And there it is. It's a scorpion.

They won't come out for
the rest of the day, but at night,

when it gets cool scorpions all over
the desert will be emerging.

And then we have a very special way
of finding them.

In ultra-violet light,
scorpions are magically transformed.

They glow with fluorescence.

So with an ultra-violet torch,

you can get a better idea of just
how abundant scorpions actually are -

even in this arid wilderness.

That's because they have managed
to develop external

skeletons that are virtually watertight.

They also have powerful stings

and pincers so getting together
to mate could be dangerous.

A male looking for
a female must be careful.

She is powerful enough
to kill and eat him.

So he begins to dance.

Is she impressed?

Apparently so -
and his solo becomes a pas de deux.

But stings are still held high,
ready to strike.

She tries to sting him.

His response is to give her a dose
of her own medicine with a quick jab.

But it's so slight it merely
makes her a little drowsy.

At last, she seems more amenable.

He pulls her to a part
of the dance ground

that is smooth and level.

He has extruded a small packet of sperm
on a stalk glued to the ground.

He maneuvers her so that as she dances
she goes over the stalk -

and takes the sperm-packet up
into her body.

The nuptial dance is over.

Her fertilized eggs stay within
a special chamber

in her body for more than a year
while they slowly develop.

And then in her burrow deep underground,
she gives birth.

She has produced up
to fifty young ones.

They cling tightly to her back
for a few weeks after birth,

each sustained by a small blob
of yolk in its stomach.

And then at last
they're all ready to venture

into the open desert for themselves.

By colonizing this,
the most hostile of environments,

the first animals to walk

on land finally broke their link
with open water.

And they did that about
three hundred million years ago

at a time when the animals
with backbones -

including our own ancestors -
were still swimming in the seas.