As their lives unfold, many creatures gather in unimaginable numbers.
And yet meeting in communal places to breed creates a huge
problem for the jealous passions
aroused by sex always threatens to tear communities apart.
So how do animals cope with sex and violence to enable them to reap the
benefits of living in extended families.
This pinnacle of granite hosts a huge gathering of gannets.
These seabirds can't nest on the sea so they're forced to
congregate on remote islands where they're safe from
terrestrial egg thieves like foxes
ln gannets, it's possible to observe how the
energy unleashed by sex can be extremely disruptive.
Every bird needs to be a fighter to defend the small
nesting territory, and woe betide any one of them which
lands in the wrong place.
A gannet's sole friend is it's mating partner.
For this is a colony of hostile strangers, forced to interact.
When tempers fly, no quarter is given.
Occasionally birds are mortally wounded.
And yet in this seabird city there are rules,
lmmediate neighbours recognize an armed truce,
After breeding the gannets disperse,
but in some animals the sexes co-habit all the year round.
A situation fraught with even more tension.
Dawn in the highlands of Ethiopia
Gelada baboons emerge from their sleeping ledges
to embark on another busy day.
Although intensely gregarious these ground dwelling creatures
live with an undercurrent of fear and intimidation.
Foremost among those that spread terror are the dominant males
The males use force to get what all males want,
as many females as possible.
For them, aggression pays,
and turns them into Machiavellian despots with pressing sexual drives.
ln his prime a male Gelada can gather round him a harem of six or seven wives.
Sex causes a great deal of tension because each male
lives alongside hot tempered tyrants
who constantly threaten to abduct his females.
This male is still so wound up that he mates to dissipate his stress.
ln many primates, copulation is not merely for reproduction.
Female geladas can't live with a high level of aggression,
they want to be left in peace to rear their offspring.
So they've got ways of preventing their despotic
male from behaving too badly.
lnviting him to groom them and grooming him calms tense situations.
Picking through each others fur also
reinforces social bonds, or friendships.
But if the male starts to bully one
of his wives they all gang up and retaliate.
and the tyrant doesn't always get his own way.
Yet paradoxically the females need fierce guardians
to protect them from being sexually harassed by unattached males.
There's no shortage of them
Gangs of frustrated young bachelors lurk around the edges of the troop.
Sexually mature, they each yearn for their own
family of females and frequently make trouble for everyone.
lt's a universal social problem,
how to control the aggressive tendencies of young males.
Their rampaging causes chaos and challenges
the authority of the harem-holding males.
Such meetings can only lead to a simian showdown.
This male puts on an act of bravado, but he's greatly outnumbered.
But their victory is short lived. The furious male scatters the gang.
One day this tyrant will meet his high noon
and lose his females, but not today.
He broadcasts his triumphant
win to the rest of the troop from the top of a tree.
These, too, are dangerous thugs.
When provoked, male lions act with great savagery,
but they're kept in check by a surfeit of sex.
The family, or pride, revolves around the number of related lionesses
who help each other rear the cubs.
They depend upon a coalition of warrior males,
usually brothers and unrelated to them
to repel other prides from their hunting ground.
The guardians are regularly challenged by younger males like these,
looking for lionesses of their own.
As time passes, the threats become more serious.
At the prospect of a battle,
the females and cubs make themselves scarce.
The residents are defiant,
so a demonstration of male power is inevitable.
After their brutal mauling the overthrown brothers withdraw.
After several years in charge they've had their day
Now the interests of the new males and those of the lionesses differ.
Without their fathers to protect them, the cubs are in peril.
They're systematically hunted down and dispatched.
The lionesses have no defence against the males superior strength.
For the mother a year's parental effort is wasted.
But for the males the loss of a cub is in their interest.
lt causes the bereft lionesses quickly to come into season.
However the lionesses need a strong coalition
of males for their future protection
so they must prevent them fighting over sex.
They do this by being sexually insatiable.
As each lioness comes into heat,
she demands to be mated every 20 minutes.
Over three days, a lioness can copulate three hundred
times, when one male has had enough she allows
the other to take over, keeping them both happy.
Three months later, the lionesses start producing new batches of cubs.
But these little creatures now have nothing
to fear from their awesome guardian.
The mothers have cleverly confused the issue of paternity.
As both brothers mated,
both males must work together to protect the family,
until one day, they too will be deposed.
But if females really want the upper hand
they must beat males at their own game.
Such is the case with spotted hyenas.
Fighting for a share of
carcasses is what has shaped the hyenas body.
ln these feeding scrummages, being big and brawny is what counts.
lt's especially true of female hyenas with cubs to suckle.
Hyena clans are dominated by a breeding matriarch.
Souped up on testosterone,
female hyenas behave like aggressive super-males.
They even possess an erectile structure similar to a penis,
which is shown off in a display of rank when hyenas meet.
For the clan leader the survival
of her pups depends on her irascible nature.
She nurtures her family for nearly two years.
So she needs to fight for food to fuel her milk supply.
Male hyenas are wimps,
they are completely subordinate to he butch females
who force them to the bottom of the clans pecking order.
Here even an infant female manages to hassle her much
older brother, who cowers with his tail between his legs.
The matriarch's over-riding influence
on the clan is revealed inside her den.
Amazingly she can somehow choose the sex of her offspring.
When food is abundant, she gives birth to fierce daughters,
who would enhance the size and power of her pack.
But during unfavourable times, she produces sons,
who leave the territory and perhaps spread
her genes into neighbouring clans
Many animals live in groups
so they can defend and maintain something important to them all.
ln social insects their lives revolve around the nest.
Termites, bees, ants and wasps appear
to be willing slaves to a common cause but they're not.
This pile of sticks on the Brazilian pampas houses huge insects.
These are workers of the primitive dinosaur ant,
a finger length giant, which lives in communities of 80 or so.
They are all identical females and equal in status.
All except one.
She's different in one crucial respect.
On her honeymoon, she was mated by a male and stores his sperm.
She's the only ant in the nest who can lay fertilised eggs,
which hatch into yet more female workers.
She's become a kind of queen by bullying tactics.
She also rules her family by chemical power.
Maintaining her control by secreting a substance from the tip of
her abdomen which her workers crave.
The queen - on the right -
applies it to other ants' antennae, and it's powerful stuff.
Her subjects even cower before her like a dog before it's mistress.
Under the influence of the secretion, the females obediently become slaves,
maintaining the nest, foraging and butchering prey.
While the queen leads a life of comparative leisure,
eating and laying eggs, her sexually suppressed daughters,
toil away tending her brood.
A raft of ever ravenous grubs receive
constant attention from their elder sisters.
Eventually these helpless grubs pupate
and hatch as female ants to be pressed into service by their mother.
Although this family of dinosaur ants looks like
a smoothly running operation,
there is an underlying struggle for power.
Every worker can potentially breed.
And occasionally one tries to.
Here a rebellious female attempts a coup d'etat and
tries to enlist the loyalty of some of her sisters,
by producing her own queen substance.
But the workers recognize her as an impostor and pin
her down perhaps for two or three days to be
beaten up or re-anointed with the true queen's secretion.
So long as the dominant female can maintain control
it benefits her to have as many slaves as possible.
But there's a limit to how many subjects
a queen can physically suppress.
A genetic battle is waged by queen honey bees.
Up to 60,000 female workers help to maintain a honey bees nest.
The queen - the one in the centre spends all her time laying eggs,
one every few minutes.
Like dinosaur ants, she too employs chemical secretions
to control her enormous family.
They're licked from her body.
The queen breeds a huge family of sisters.
Due to a peculiarity of genetics,
the workers are much more closely related to each other,
then they would be even to their own offspring.
So the workers help their mother rear more sisters,
rather than breed themselves.
The nest is a vast factory hatching two
thousand new workers a day, ready to gather nectar and pollen,
during the brief flowering season.
lt seems bees have a utopian way of life.
But back on the combs, the queen has a problem.
lt's not just nectar that the workers deposit in the cells,
Some like this one, lay their own eggs.
An act of rebellion.
Being unfertilized they would produce male bees, drones,
and compete with the queens own sons.
A situation not to be tolerated.
Curiously these sneaky breeders get no help from their sisters.
And they don't because the queen
has already counter attacked during her aerial honeymoon.
Smelling irresistible she was pursued by numerous drones.
Needing sufficient sperm for years of egg production
she mated with up to 30 of them.
The daughters she subsequently created are therefore not as
closely related to each other as was once thought.
Derived from different fathers, many workers are only half sisters.
And not disposed to help each other.
While still protecting eggs smelling of their mother,
workers search out and eat their half sisters eggs.
So by being promiscuous, the queen has created her own police force.
She wins this genetic battle and keeps control.
But in another group of animals, there's not even a chance of rebellion.
Spurred into activity by rain, teams of naked mole rats extend
their network of tunnels into the softening earth
under the African Savannah.
ln a matter of days, they'll dig over two miles
of passageways and create tons of spoil
Back in the central nest chamber, the single reproductive female,
the queen, bloated with babies resides on a mattress of oppressed males.
She's a hefty tyrant who suppresses the sexual
drive of her smaller daughters, by constantly chivvying them.
She even starts to bully her brood by trampling on her new born babies.
The queen acts from selfishness to survive she needs organised labourers,
because for most of the year, the ground is like concrete.
Then when it is briefly softened
by the rains her slaves must work against
the clock to find sufficient roots and tubers for the rest of the year.
Mole rats are forced to work together by their mother.
But not so in this family of banded mongooses in which team work benefits all
Some willingly forego producing their own offspring.
Whereas all of the adults could breed only a few do so.
Out of a family of twenty, perhaps only four females are sexually active.
These mongooses would not survive in the
African Bush unless they had a highly co-operative lifestyle.
For them, there's safety in numbers.
Some individuals which have abstained from sex
have even developed special roles in the extended family.
While the rest are hunting, some males remain in the den.
The youngsters, although inquisitive,
have yet to become wise to the dangers
of the bush, so they are often protected by a babysitter.
A few non-breeding females even wet nurse their sisters babies.
Such individuals are happy to help
because they are breeding indirectly.
Their nieces and nephews carry some of their own genes
The advantages of family life are plain to see
A marshall eagle.
A warning by one of the baby sitters causes the troop to return to the nest.
Surprisingly, quarrels over sex are rare,
and how mongooses manage to keep the peace is a mystery.
But in a highly gregarious ape, it's not
Bonobos are related to chimpanzees,
and have evolved in isolation in the forests
of the Congo where they live in tight family groups.
Noticeable is the placid atmosphere that reigns among them.
The individuals stick together as they forage around the forest.
Even an explosive argument
boils down to the aggrieved thrashing
a branch rather than resorting to violence.
But most significant of all sex and sexual
play has been adopted as a way of appeasing each other.
After an argument males make genital contact,
the bonobos' way of shaking hands.
Sex and genitalia, the very currency of power between
the sexes are continually on show and become social
assets rather than demonstrations of dominance.
Young and old alike freely engage in brief bursts of sexual behaviour.
ln this context it's ritualized but none will lead to conception.
When females are ready to conceive, their male bonobos
compete genitally with each other,
but for most of the time social stresses are gently dissipated.
This use of sexual behaviour by these erotic apes is exceptional.
ln most species sex brings
males and females into sharp conflict often with wasteful consequences.
So why do animals bother with sex at all?
An intriguing question that's explored in the next episode.