All language subtitles for Trials of Life 09of12 Friends and Rivals 720p BluRay x264 DTS GOTEi MVGroup

Eagles lead lonely lives.

This one, flying over
the gaunt mountains of northern Scotland,

may spend days
without seeing another of its own kind.

In spring, when a pair are raising
one or, at the most, two chicks,

young rabbits and birds are not difficult to find.

But now, late in the year, food is scarce,

and there's barely enough
on this bleak hillside to support a pair.

The chicks had to leave
to find hillsides of their own.

So an eagle doesn't have to deal
with the problems that face

and can even dominate
the lives of more sociable animals.

Unlike the lonely eagle,
many animals live in groups.

But that inevitably causes problems.

How do you get on with your friends and,

more particularly, your rivals,
without continual squabbles?

There's another big bird in these Scottish skies,
bigger even than the golden eagle.

It comes here in the autumn
and then it forms large flocks.

Hooper swans, coming in to land
after a 1,000-mile journey from Iceland.

There the winter will be dark and bitterly cold,

and the birds have flown down
to spend the winter here

in the milder conditions of Scotland.

Suitable stretches of water, secluded, with
plenty of vegetation around to eat, are few,

and this loch will soon be crowded.

Some of the arrivals
are young birds travelling by themselves

who have yet to find a mate.

The next few months will be their opportunity
to form partnerships that will last a lifetime.

Most are families, pairs with their
six-month-old cygnets hatched in Iceland.

They will stay together until the next spring.

They proclaim their arrival
with a clear challenge to those already here.

They, too, intend to claim a place on the lake.

The male fights most of the necessary battles.

But his mate always backs him up,

and the pair celebrates a successful skirmish
with an ecstatic triumph ceremony.

There's a clear pattern to these encounters.

Pairs consistently win against singletons.

But the most dominant and successful of all
are the families: mother, father and cygnets.

This is a particularly powerful one.
It has four young.

Singletons or even pairs
who come too close are quickly seen off.

The cygnets enthusiastically join
in the triumph ceremonies.

As long as they stay close to their parents,
they will be treated with respect by other birds.

But if they stray, they will be shown no mercy.

The parents will fight others
on behalf of their young.

The cygnets will stay with their parents
until the spring

when they'll be strong enough
to fight their own battles.

In the meantime, other members of the flock

come to recognise and respect
the most powerful families

and avoid confrontations where they can.

An apparent peace breaks out on the lake.

0ther swans give the family a wide berth.

The cygnets can now swim and feed
without arguments.

But not all seniorities are settled
in such a straightforward way,

particularly within groups.

Chickens, when allowed to range
freely in a farmyard, as these are,

form themselves into small, tightly organised

and remarkably stable groups.

Usually there's a cockerel
and then a number of hens around him,

and maybe one or two
other cockerels on the sidelines.

0ne of the first studies ever made

to find out how animals organise
themselves in groups

was done with a group of chickens like this.

If there are ten or less in the group,
then every bird knows every other individually.

They move in a flock,
scratching around for whatever they can get,

apparently harmoniously.

But if I give them something they really like,
then they reveal their true competitive nature.

Watch this.

This pale hen is particularly aggressive.

If she doesn't get to the food first,

she'll peck those who do so
until they give way to her.

This dark hen behaves in the same way

and pecks everyone
except the fierce pale hen, whom she avoids.

The result of these skirmishes is a peck order,

a line of seniority
in which each bird knows its place.

Should the lowliest hen at the bottom
of the peck order find a coveted morsel first,

she'll be chased and harried
by all the others until she gives it up.

Clearly, all hens are not equal.

Dominant ones hand out the punishment,
junior ones get henpecked.

But for most of the time, the relationships
between them seem very friendly,

and the flock leads a quiet and productive life.

It's the same with the cockerels.
They, too, avoid confrontation.

But every now and again, the senior cockerel
has to remind the junior who is boss,

just in case they get it into their heads
that they want to steal his crown.

(C0CKEREL CR0WS)

Such peck orders occur in the wild as well.

A group of caciques
has established a colony high in a tree

overlooking the Manu River in Peru.

The males established who was senior to whom
early in the breeding season

with a series of disputes that none has forgotten.

And those now determine
who will get the pick of any food around

and, more importantly, who will consort
with a female when she's ready to mate.

The males compete for the right to display
beside the clustered nests

which were built and are occupied
by individual females alone.

A subordinate male
will always give way to a dominant one,

just as chickens do in a farmyard.

It's a waste of energy to go on fighting
the same battles when the outcome is the same.

The juniors snatch a mating if they can,

but they may not succeed
unless they move up in the rankings.

So why do caciques put up with the tensions
of social living, rather than going it alone?

The reason becomes clear
when the colony is threatened.

A toucan, an avid eater of eggs and chicks.

A single cacique is unlikely to deter a toucan.

But all the members of the colony together,
with their differences forgotten,

can mount a highly effective defence.

This nest is empty.

But this one isn't.

A capuchin monkey,
another most determined raider.

So even subordinates in this community have
a better chance of producing surviving chicks

than if they were to nest in isolation
with no effective defence against raiders.

Lions, too, live in groups.

The lionesses form the core of the pride.
There may be a dozen or so,

all of them closely related,
mothers and daughters, sisters and aunts.

And it's the lionesses
that do most of the hunting.

The two or three males,
often brothers, fought as a team

to drive off their predecessors
and join the pride.

They will fight again
if newcomers try to displace them.

But, most of the time, they have a peaceful life.

Living in groups, for the lions,
brings several advantages.

For one thing, they can tackle large,
powerful prey, such as buffalo.

These huge animals
are three times the weight of a lion.

A single hunter would be very unlikely
to tackle a healthy adult buffalo.

It simply wouldn't have the weight
and strength to bring one down,

and it might well get injured in the attempt.

But a pride, working together, has a chance.

A preliminary chase serves to get the measure
of the quarry and to isolate an individual.

If one seems weaker than the rest,
it will become the target.

The lions attack.

Despite the numbers pinning it down,
the buffalo is still dangerous.

It's finally killed and the feasting begins.

What about seniority and rank in this group?
There's little squabbling or fighting.

This kill has produced
such a huge quantity of meat

that there is more than enough for everyone.

So those who haven't got a place
at the carcass amiably await their turn.

And that is just as well.

Such lethally armed hunters
as these brothers and sisters

could easily kill one another
if a dispute became violent.

0nly in very hard times,
when the pride is extremely hungry,

will issues of priority be settled by fighting.

Lions, cooperating in prides,

dominate the harsh and ruthless world
of the African plains.

And the secret of that success
is their cooperation.

When they work together,
no other hunters can match them.

This cooperation extends
into other parts of their lives as well.

The lionesses nurture their cubs as a team,

taking turns to guard them and even,
on occasion, suckling one another's infants.

Baboons live in even bigger groups,
up to 150 or so.

This gives their young,
who are defenceless for several years,

the protection that comes from such numbers.

This troop in Kenya is waking up,

having spent the night in the relative safety
of its regular sleeping cliff.

Within a baboon troop, there's a fine balance
between friendship and rivalry.

Like lions, their societies consist largely
of closely related mothers and their young,

and it's the adult females
who largely control affairs.

The powerful males are all outsiders

who only gained acceptance to the troop
by making friends with one or more females.

Grooming is one way
that they established such bonds.

Taking charge of a female's baby is another.

A ferocious male can treat an infant
with great tenderness,

which is the more remarkable when
you consider he may not even be the father.

In baboon society, a social favour like this
will be remembered by the mother

and may improve the male's friendship with her

and the likelihood of him fathering her next baby.

Males consolidate such relationships
by encouraging females

to join them for a careful grooming.

Encounters with rival males,
however, must be handled carefully.

Lip smacking here is a gesture of appeasement.

Males pull other strange faces to act
as clear come-on signals to passing females.

Meetings can serve several functions.

Seniorities and friendships are reaffirmed.

Babies begin to learn the complex language
of smells, gestures

and the importance of social relationships.

By caring for an infant, a male demonstrates
his commitment to its mother.

And the babies, playing together,
learn about making friends,

as they must if they're to achieve
a good social position later in life.

This babysitter misses the chance
of making friends with a passing female

because he's surrounded by jealous males.

If he had abandoned the baby,
there might have been a squabble.

As long as he holds onto it,
he will be left alone by his rivals.

But he has plenty of other opportunities.

Being a good father figure makes a male
a great favourite with the females.

A young female passes the time of day,

but she's not sexually receptive and he's busy.

In this complex society,
social tensions can easily lead to conflict.

When a female is threatened
and pursued by one male,

she'll seek out another who is
a regular ally and cling to him for support.

With a friend to help her, she's now safe,

and, between them, some hard staring
is enough to see off the aggressor.

For baboons, it's not how big you are
but who you know that counts.

Arguments and squabbles
between adult animals

striving to maintain their position
within their community are common enough.

But acts of assistance, in which one
adult animal goes to the aid of another

that's got itself into difficulties,
these are much rarer.

But this sort of behaviour does seem
to occur regularly in one species of animal,

a colony of which is living in this hollow tree.

It's not an animal
that might immediately come to mind

as an example of a caring, unselfish creature,
but that, apparently, is what it is.

0n this pile of droppings
there are flecks of congealed blood,

a characteristic sign of vampire bats.

And the colony itself is roosting above me.

These bats, all females,
habitually roost as a group.

If they move elsewhere, they will stick together
and hang in the same arrangement.

Most are related, although by no means all.

But every bat knows
her regular companions well.

At night, they fly off to look for blood.

A donkey is a favourite target.

0ne lands on its shoulder and shaves
a slice of skin without the donkey even noticing.

Another goes for its ear.

The bat's saliva contains an ingredient
that prevents blood from clotting,

and it flows freely from the wound they make.

A third bat tries a different point of attack.

(D0NKEY BRAYS)

The bat on the ground still hasn't got a hold,

but it's very hungry
and it makes one last attempt.

But, no, she won't feed tonight.

0n returning to the roost,
she hangs up beside an old friend.

She turns to her neighbour and licks
her face repeatedly, begging for food.

If she goes hungry
for more than a day or two, she will die.

But her friend regurgitates
enough life-giving blood

to keep her going until the following day.

0n another night, the situation may be reversed,

and the bat that is receiving now
will repay the gift if it's needed.

But cheats, bats that refuse to give
to a neighbour who once helped them,

will quickly be detected and, in consequence,
may never be helped again.

So, for a vampire, it pays to help your neighbours,
whether they're related or not.

Look after them and they will look after you.

Such mutual assistance is much more common

among communities
whose members are closely related.

Dwarf mongooses live in groups of a dozen or so

in the tunnels of old overgrown termite hills,

and most of them
are the children of one breeding pair.

This is the old female. While she is alive,
no other female here will breed.

And this is her mate, the old male.

They feed almost entirely on insects

which they scratch out of the ground
and from rotten logs.

Every day the troop goes out to collect them.
It's a very time-consuming business.

A nice, big, crunchy beetle.

But digging like this has its perils.

With your head in a hole,
you can't see if an enemy approaches,

and with your rump in the air,
you're dangerously exposed.

So while some hunt, other members
of the colony are on guard duty.

These sentinels,
usually males, but sometimes females,

will get their turn to feed in due course.

The youngest babies are now coming out.

Their mother can't always be with them.
She has to spend much of her time feeding.

Junior members of the colony
take turns to babysit.

0ne or two of these babysitters
may replace the old breeders one day,

but, for now, the best
they can do is to serve the colony.

In doing so,
they may promote their own genetic line,

for the nurses are often
the older sisters of the babies

who carry as many of their genes
as their own young would.

A martial eagle, a most dangerous enemy.

The sentinels keep a close eye on it
to see if it's coming their way.

If it does, they will whistle an alarm signal.

(WHISTLING)

The nurses groom their charges,
play with them and catch insects for them.

Though they have never been pregnant,
they may even come into milk and suckle them.

By the middle of the day, it's very hot
and many of the group need a snooze.

And it's safe for them to drop off

because some members of the family
are still on guard.

So, by taking turns to help out
and waiting for a chance to breed,

the mongooses are able to survive
and continue their family line

where as pairs they would surely fail.

0ne mammal has taken this specialisation
within the community to an extreme.

Just how extreme hasn't been
appreciated until quite recently.

That's hardly surprising,
because the most anyone normally sees

of this amazing creature is no more than this.

It's a powerful and industrious digger
that spends its entire life underground.

A naked mole rat.

These creatures live
in highly inbred groups of 80 or more

and feed on the gigantic underground tubers
developed by some desert plants

as a way of storing food and water.

But they have no way
of knowing where these tubers are.

All they can do is dig away and hope
they will eventually bump into one.

So the colony is perpetually tunnelling.

Digging in this hard ground requires teamwork.

Some workers, at the front end of the tunnel,
gnaw into the baked earth.

A mole rat's lips close
behind the long, curved front teeth,

so that it doesn't get
any of the earth into its mouth.

0ther team members, behind,
kick the soil back along the tunnel

until it reaches one of the surface exits.

It's so unvaryingly hot here
that the mole rats need no fur.

Because they're hardly ever
in the light, eyes are of little use,

and they're virtually blind, so they run
backwards and forwards like tube trains.

Not all the mole rats dig.

A few, a little bigger than the tunnellers,
spend most of their time lazing about

in a large central chamber.

These are soldiers.

Some are male, some female. And they're
saving their energies for an emergency.

And here comes one.

A snake has found its way
down one of those exit holes.

The workers flee in front of it,
squeaking with alarm to rouse the soldiers.

With those formidable teeth,

the soldiers are capable
of stabbing the snake to death,

and they block the tunnel.

(SQUEAKING)

Reinforcements arrive.

The snake thinks better of it.

The mother of the colony, the queen,
is the only breeding female.

She gives birth to a dozen or so young at a time

and produces a new litter every 13 weeks.

And she may live for 12 or 13 years.

The father of the brood is one or other
of the two oldest soldiers.

But he's not as long-lived as the queen.

A year or two of sexual activity
seems to exhaust him and he dies.

His place will be taken
by another senior soldier.

All these babies will become tunnellers.

Some will later graduate to being soldiers,

but none of the females, while the queen lives,
will become sexually mature.

Why?

The colony has a communal latrine,
used by all, including the queen.

The workers, when they visit it, deliberately
anoint their naked skin with its contents.

This gives them the colony's odour,
so they are recognised and accepted by all.

But in doing that, they may commit
themselves to a life of sterility,

for the queen's urine contains a substance

that helps to suppress
the development of ovaries in others.

The supply of the fertility suppressant
will continue as long as the queen lives.

0nly when she dies will one
of the female soldiers mature sexually

and succeed to the throne.

The queen spends most of her life
in the chamber surrounded by her soldiers.

She doesn't dig. She doesn't fight.

She concentrates her physical strength
on producing within her belly

huge broods of babies.

So the ranks of the short-lived tunnellers

are maintained to continue
the digging that's essential

to find food for themselves,
their brothers and sisters and their queen.

These hard-working porters
are also members of a society,

but one which numbers
not a few dozen but several million.

Nor are they just gathering straightforward food.

They're taking part in a much more
complex agricultural system.

Leaf-cutting ants demolish plants
morning, noon and night.

Heavy rain and direct sunshine
are the only conditions that stop them.

Every one of these workers is a female.

They're all sisters,
working together in one of the most organised

and tightly knit communities of all.

They use their legs as callipers,

guiding their jaws
so that they cut a segment of a size

that is the most economical to cut
and most practical to carry.

But they can't eat these leaf segments.

Cellulose, the main constituent of leaves
apart from water, is very indigestible.

They have to take all these pieces back
to their underground nest for treatment.

The journey may be down
a tree trunk for 50 feet or more.

And once on the ground,
there may still be 100 yards to go.

0nce inside the entrance of the nest,

the leaves are carried down long corridors
deep below ground.

Here, in special chambers, they're taken over
by a slightly smaller caste of worker

who cut the leaves into smaller segments still.

These chambers are gardens
where the colony cultivates a special fungus.

The leaf segments are the raw material
on which the fungus will grow.

But, first, the segments must be processed.

It could be very damaging
if bacteria or spores of an alien fungus

got into the nest
and started to germinate like a weed.

So the workers meticulously clean
the surface of each piece by licking it.

The edge of every segment is then chewed.

This yields some food
for the worker doing the job,

for leaf sap is digestible.

And it also prepares the leaf for the next stage.

The garden chambers vary in size
from an orange to a melon,

but they're all filled with a honeycomb
of grey, spongy material.

And now these smallest workers of all take over.

They're a mere two millimetres long,
the size of a grain of sand.

0nly these tiny dwarfs can enter
the minute spaces within the gardens.

They push the leaf fragments into the matrix

and then plant tufts of fungus
all over their pulped surface.

Within 24 hours, the green of the leaf
has almost completely disappeared

beneath a tissue of white threads.

A day or so later and the threads of fungus
begin to develop tiny knobs at their ends.

This, at last, is the crop
that the ants can eat.

Some of the workers consume it there and then.

Most is carried away to feed to developing grubs

and the other workers who laboured so hard
gathering the leaf segments in the first place.

0ne by one, these swollen ends of the threads
are torn from the tangled mass.

Sap, sucked from the edges of the leaves
during their processing,

is fed by a gardener to another worker
who has duties elsewhere in the colony.

Slowly, the swarms of workers
complete the harvest.

Now the fungus is spent.

Its remains and the mulch of leaves on which
it grew has to be cleared out of the garden.

The workers swarm all over
the grey honeycomb, breaking it up.

Every particle is carried up the corridors
and taken out of the nest.

Long processions of workers set off for the exits.

Here, out in the open, by the side of the nest,
they have their refuse tip.

So one cycle of fungus cultivation is completed.

And the scale of their operations is enormous.

They can strip an entire tree
of its leaves in a single night.

Their pathways extend
for 100 yards in all directions.

The nest is 20 feet across
and it goes down for as much as 18 feet.

Inside, there are a thousand or so chambers

where the ants have their gardens
and where they live.

And it's virtually impregnable.

Even the vibrations of my footsteps
are enough to bring out the defenders.

These soldiers are 300 times heavier
than the little dwarfs working in the gardens.

They bite any alien thing -
shoes, socks, anything.

As long as they only bite my clothing,
they're no problem.

If they got onto my flesh,
they would have me hopping about,

for they can slice a very painful slit in your skin.

They seldom let go. 0nce they've fastened
their jaws, they stay fastened,

even if the rest of their body gets torn off.

Soldiers are expendable.

Their task is to protect the one single individual
in the colony who is indispensable.

The queen,
mother of all the members of the colony.

She is as big as a newborn mouse.

0n her nuptial flight, she was impregnated
by three or four males.

The sperm they gave her then lasts her
for the rest of her long and productive life.

The workers continually groom and clean
every part of her great body.

Some attend her rear, waiting to collect
the eggs she produces in bursts.

She may lay a million a year.

Some are fertilised from her sperm store,
others are not. But they, too, will hatch.

0ne appears, a tiny white bead.

A worker waits for it to emerge completely,
feeling it delicately with its jaws.

It picks it off
and takes it away to the nursery chambers.

The grubs that develop from fertilised eggs

mostly become members
of the exclusively female workforce.

The way they are fed by the workers

determines which
of the six different castes they will be.

Unfertilised eggs develop into males,

who fly out of the nest to mate with young
winged queens and establish new colonies.

0nce these ants start on adult life,

they will not be able to change roles,
as mole rats or dwarf mongooses can.

Their destiny is fixed.

The first ants, back in the evolutionary past,

almost certainly operated as single individuals,

as many species of their wasp
and bee relatives still do today.

0ver millions of years,
they came to live in communities

of increasing size and complexity.

Now that process has come full circle.

By producing individuals specialised
to do particular jobs in their society,

five million insects have become effectively one.

But what a superbly efficient one.

It's not the monkeys or the rodents or, indeed,
the human beings who dominate the forest.

It's the tiny ant that, by multiplying itself,

has turned itself into a super-organism,

a complex, highly disciplined society.