In the last 6,000 years
the surface of our planet has undergone a sudden change.
A new habitat has appeared,
entirely designed and constructed by one species for its own purpose.
This man-made landscape may seem alien to animal life
but for the bold, this is a world of surprising opportunity.
Jodhpur, India.
A gang of bachelor male langurs
has come to challenge the resident alpha male.
This alpha rules over a valuable urban territory.
But maintaining dominance here is a constant struggle.
The bachelors have united to try and overthrow him.
If they win, one of the challengers
will take over the alpha's troop of females,
and may kill his infants.
There are 15 males in this bachelor group.
The alpha must evict every single one of them from his territory.
He has chased half the bachelors away,
but a splinter group has looped back and is harassing his females.
Once again, he has to battle.
Finally, he manages to expel them all.
He returns home victorious,
but with a serious wound on his right leg.
It's a hard life for him in the city.
Keeping the intruders away is a daily challenge.
But it's worth it.
For these urban territories
are probably the best langur territories in the world.
They're filled with rich feeding grounds.
Here in the temple gardens,
the langurs have, over centuries, developed a surprising relationship.
One that guarantees them a constantly replenished source of food.
The people here associate langurs with the Hindu God, Lord Hanuman,
and revere them.
They're given all the food they can eat.
And this high-energy diet has led to a baby
Female langurs in this city
give birth to twice as many young as their forest counterparts.
This mother is so well fed that her rich milk
can support something rarely seen in the wild.
Twins.
And all these babies can create troops
that are far larger than those found in the forests nearby.
With less time spent looking for food, there is more time for play.
The rewards of living in a city can be huge.
The challenge is to find your niche.
But how to create a home in a world that wasn't designed for wildlife?
It's far brighter, louder and busier than anywhere in the natural world.
The continuous traffic creates barriers to animal movement.
And in this decade, the urban environment
Is predicted to grow by nearly 30%.
What's more, to come here,
animals have to compete with the world's top predator.
People makes the rules here.
Four billion human beings now live in the urban environment.
It's here that animals have to contend with the greatest change
that is happening to the face our planet.
So why would any animal want to come here?
New York City.
This densely built-up landscape Is as unnatural as anywhere on Earth.
And yet, this wild peregrine falcon looks out onto an ideal habitat.
Strange as it may seem, this vastly-altered landscape
replicates the conditions in which peregrines evolved.
The towering buildings have a multitude of ledges
on which falcons can nest,
and the high perches that they need to catch the wind.
New York City has the highest density
of nesting peregrines anywhere on the planet.
Winds striking the sides of the skyscrapers
are deflected upwards and can help the birds gain height.
And the great areas of concrete roasting in the sun create thermals,
so that, with very little effort, the birds can soar over the city.
And so many peregrines can live here,
because down at street level there is a lot of potential prey.
Diving from height, the falcons can reach speeds
of over 300 kilometres an hour.
But their prey stay down low and close to the buildings.
Too risky.
The peregrine pulls out of his stoop.
But the effort is not wasted.
The falcons need to flush their prey into the open.
And Manhattan is surrounded by water.
Out here the odds change.
And in the peregrine's favour.
With abundant prey here all year round,
it has taken only 40 years
for these falcons to establish themselves here.
And now, among skyscrapers, they're more successful
than their cousins living in the wilderness.
Mumbai, in India, is home to over 20 million people.
And there are predators here
that, though rarely seen, are rightly feared.
Carnivores,
lured by the prospect of plentiful unsuspecting prey
are on the prowl.
A leopard.
Every night, under the cover of darkness they come out to hunt.
These are big animals,
and they're looking for large prey to satisfy their hunger.
To catch more than a glimpse of them and reveal their hunting behaviour,
you need night-vision cameras.
Leopards have attacked almost 200 people here
in the last 25 years.
But humans are not their usual prey.
These leopards are on the hunt for something else.
Pigs.
These leopards prefer to hunt the domestic animals
that people have brought to the city in considerable numbers.
The pigs keep their family close.
The ceaseless noise of the city plays to their advantage.
It conceals their approach.
And the leopards are using this cover to hunt all over the city.
This is a thriving population.
In fact, the highest concentration of leopards in the world
is right here.
It's not only the abundance of food that attracts wild animals to cities.
They're usually several degrees warmer than the surrounding countryside.
And here in Rome, in December,
one animal is taking full advantage of this extra heat.
And it's leaving it's mark.
In a single winter's day,
ten tonnes of its droppings rain down on the city.
Starlings.
In the evening, they come back to the warmth of the city
after feeding in the neighbouring countryside.
They must return to their roosting trees.
But the first to do so are at the highest risk
of being caught by birds of prey.
So, they wait for others to arrive.
There's safety in numbers.
As daylight fades, the sky fills with a staggering one million starlings.
And then follows one of nature's great spectaculars.
How, or indeed why, they perform these marvellous aerobatics,
we still do not fully understand.
Eventually, en masse, they brave the descent
and fill the branches of their favourite trees.
On these cold winter nights, the city's extra warmth
can mean the difference between life and death.
A city, of course, can provide
not only shelter and abundant food, but glamour.
These varied objects have been carefully chosen
by a bird for their brightness and their colour.
This great bowerbird has spent over a decade
building this collection of mostly man-made objects.
Out on a golf course in Townsville, Australia,
he's putting the final touches to his enormous bower,
that he hopes will impress a visiting female.
He spends two hours each day rearranging his prized objects.
"Perhaps that would look a little better over there.”
But it seems that something is missing.
Instead of going into town to collect new objects,
he's decided to raid his neighbour's bower.
"A clothes peg! Excellent!”
"And a shiny toy car.”
It's a risky game if you get caught.
The owner is back.
There is one bower where the risk is worth it.
A particular object has caught his eye.
He'll have to wait for the owner to leave.
This is his chance.
A real treasure.
A scarlet heart.
"Got it."
The stage is now set for female visitors.
His luck may be in.
The seduction can now begin.
He's showing off his best goods.
"Perhaps a little plastic piping?
"Or maybe a bit of coloured string?”
But his guest doesn't seem to be paying much attention.
"A fork?
"Madame?"
Nothing seems to be working.
Something is just not quite right here.
But he still has one trick up his sleeve.
The scarlet heart.
As a final thrill he expands the pink crest
on the back of his head.
The sign of his adulthood.
But he's made a mistake.
This is not a female
but a young male who hasn't yet developed that head crest.
And he's making off with the scarlet heart.
It's not easy finding sex in the city.
Raising a family in the city is not easy either.
It's spring time in Toronto,
and this mother raccoon has exchanged her native treetops for rooftops.
Since giving birth two months ago,
she's kept her offspring safe and warm inside a chimney.
Now, her young have outgrown their nursery.
This is her first major challenge as a mother.
The time has come to move to a new home.
She needs to get her youngster to ground level.
But instead of an easy climb down a tree,
she is faced with a vertical drop,
with little to cling onto.
Her baby's first glimpse of the urban world,
from a terrifying ten metres up.
This is the last of her litter to be brought down.
Its siblings are already
busy exploring the area.
And they have much to learn.
This one has fallen into a back alley and is trapped.
Mother comes to the rescue and demonstrates what must be done.
That's the way.
Raccoons are opportunists.
And they're eager to explore.
But they'll have to learn very quickly
how to get along in this strange new environment
so full of hazards.
Mother comes to the rescue once more.
Urban raccoons are now demonstrably better
at problem-solving than their country cousins.
When the feeding opportunities are this good,
the time spent working out how to get to it
is well worth it.
The complexity of urban life
favours the clever.
But to compete with humanity during daylight hours,
takes more than just intelligence.
It takes nerve.
One enterprising species of monkey
has moved into the city of Jaipur in India.
The Rhesus macaque.
But how to get a share of all this juicy fruit?
Every morning, the troop make the same journey
through the urban jungle, Just as human commuters do.
Sometimes, inevitably, there are traffic jams.
Once they get to the market, trouble begins.
Being both intelligent and brazen
Is the key to beating human beings on their home turf.
It's daylight robbery.
There are some animals that most would consider too dangerous
to tolerate in the city.
Spotted hyenas.
They're feared throughout their range.
In the outskirts of Hara in Ethiopia,
two clans are coming face to face to battle over a prized resource.
There are about 60 hyenas in each clan.
And they're well matched.
After three hours of posturing back and forth,
the losers retreat
and the victors head to claim their prize.
They have been fighting over access to the city.
Once inside the city walls, they head for one place.
And they know exactly how to get there.
The ancient meat market.
The scent of all these carcasses lies heavy in the air.
This tradition goes back over 400 years.
The human butchers put out the bones they don't need
and these hyenas deal with them.
They're the only animals that can.
No other here has such powerful bone-crushing jaws.
And this relationship between man and beast
has now been taken a step further.
Yousuf is calling the hyenas to his house.
He and his forefathers, going back five generations,
have been feeding the hyenas
by hand.
The inhabitants of this town believe that hyenas
provide another very important service.
Eating the bad spirits that haunt the streets.
These are wild and ferocious animals,
but once within these city walls,
they behave in a completely different way.
Throughout the rest of Africa, spotted hyenas are feared
because they kill livestock, sometimes even children.
They are perhaps the most vilified animal on our planet.
However, here in Harar,
their relationship with people is entirely peaceful.
They have won the trust of man.
Losing its fear of humans
has enabled one animal to spread into cities everywhere,
and in huge numbers.
Pigeons are by far the most successful urban bird.
Here, in Albi, in the south of France,
the pigeons come to the river to bathe.
They need to preen their flight feathers,
clean off the city dust,
and cool themselves down.
But death lies in wait.
A predator that has taken advantage
of the very thing that has led to the pigeon's success...
Their lack of fear.
As the pigeons bathe, oil from their plumage flows downstream,
and is detected.
A monstrous Wels catfish.
Introduced here just 40 years ago, they have proliferated.
Virtually exterminated the local fish stocks...
And they've now developed a taste for pigeon.
Their eyesight is poor,
so they use their barbels to sense the movements of their victims.
This is a radical new hunting strategy
for what is normally a bottom-dwelling fish.
After a thousand years of living in this city,
pigeons are now having to learn to avoid a fish.
Our cities are always changing.
Sometimes very swiftly.
And animals must cope with the changes,
or disappear.
One of the greatest changes in recent times
has come from a single invention made less than 140 years ago.
Electric light.
It has become more and more powerful,
filling our streets with light.
It's everywhere in the city.
It even goes underground.
The difference between day and night Is becoming less and less perceptible.
And that has a profound effect on the activities of wildlife.
In the wilderness, light triggers all kinds of behaviour.
On the night of the full moon,
hundreds of tiny hawksbill turtle hatchlings
emerge from the safety of their nest deep in the sand.
Their instinct is to reach the sea as quickly as possible.
And their guide is the light of the full moon reflected on the water.
But this young hatchling is confused.
It's going in the wrong direction.
Bright light is coming from the land.
And all these hatchlings are travelling up the beach towards it.
Predators are ready to take advantage.
Crabs now make their burrows directly beneath the beach lights
and wait for their prey to come to them.
Even if a hatchling escapes,
they're still in peril.
The lights become more and more bewildering.
80% of all hatchlings on this beach
are now disorientated by the lights of the town.
Roads bring many to their end.
Hundreds get trapped in storm drains every night.
Exhausted by the effort of travelling such a distance on land,
this hatchling's chances of surviving the night are slim.
This turtle is one of the countless species
that have been unable to adapt to the change
brought about by the urban environment.
Only a small number of animals
have managed to find ways of living alongside us.
And every ten years, an area the size of Britain
disappears under a jungle of concrete.
But it doesn't have to be like this.
Could it not be possible to build cities more in harmony with nature?
How, and whether we decide to invite the wildlife back, is up to us.
This tree is rising nearly 30 storeys.
It's one of almost 800 being planted to create a vertical forest in Milan.
This number of living trees would normally fill two hectares of woodland,
but here, they occupy one-tenth of that area.
Greening the walls and roofs of our buildings
could create a rich and extensive habitat
if we wanted it to do so.
There is one city where that idea is being applied on a major scale.
Singapore.
Two million trees have been planted here in the last 45 years.
This city is now richer in species than any other in the world.
And this practice extends to all parts of the city.
The waterways have been cleaned up,
and smooth-coated otters are coming back.
But perhaps the most spectacular example of city greening
Is this grove of super trees.
These 50-metre high metal structures are now full of life.
Creepers have been planted to grow over the outermost branches.
Is this a vision of our cities of the future?
The potential to see animals thriving within our cities
Is achievable across the globe.
More than half of us now live in an urban environment.
Whether we choose to create a home for others too
is up to us.