Life

Our planet may be home

to 30 million different kinds of animals and plants.

Each individual locked in its own life-long fight for survival.

Everywhere you look, on land or in the ocean, there are extraordinary

examples of the lengths living things go to to stay alive.

This is the coast of Florida.

Here, strange scars on the sea bed

hint at one animal's remarkable strategy.

These are bottle nose dolphins,

one of the most intelligent animals on Earth.

Their prey is very elusive, fast-swimming fish.

But the dolphins have invented a completely new way of hunting.

By beating its tail down hard, this dolphin stirs up the shallow silt.

And by swimming in a tight circle

it creates a ring of mushrooming mud around a shoal of fish.

The contracting ring traps the fish just like a net.

Panicked, the fish jump to escape.

Right into the open mouths of the waiting dolphins.

Again and again, the lead dolphin creates a circle,

before they all line up with perfect timing.

These dolphins are the only ones known to have developed this hunting behaviour and it gives them an edge.

This sort of advantage may mean the difference between life and death

in the survival of the fittest.

This series reveals the most spectacular and extraordinary

strategies that animals and plants have developed to stay alive.

For every creature, every day is full of challenges,

all of which must be overcome, somehow, in order to survive.

Kenya, famous for its big cats.

The supreme hunters.

Cheetahs specialise in hunting at speed.

Though fast, they are fragile creatures,

built to sprint after small prey.

They don't have the strength or weight of a lion

to bring down larger animals.

This male is different.

He doesn't hunt alone. He's learnt that there is strength in numbers.

But here there are not just two, but three cheetahs.

A band of brothers.

They have changed their tactics and, by doing so,

have taken their prey by surprise.

They have learnt that working together

they can bring down large prey.

An ostrich.

A bird that towers over a cheetah and is more than twice as heavy.

It can't fly to escape danger, but it can lash out with a deadly kick.

A female, unaware as yet, of any danger.

Even with three of them this is still highly risky.

If one gets injured the other two couldn't hope to tackle such large prey.

On the other hand, if they get it right, the rewards

are huge.

The male has spotted one of the brothers, but only one.

It's not too worried.

Then suddenly there are three!

The female is slower to realise the danger

and the cheetahs switch targets.

It takes the combined effort and weight of all three brothers to bring down this powerful bird.

Even now the ostrich could land a fatal kick.

So far, the brothers are winning.

Ostriches have yet to find a way to foil such tactics.

Other animals have also evolved surprising tactics to outmanoeuvre

the enemy, not with brute strength but with extraordinary weapons.

Madagascar.

A strange world where nothing is quite as it seems.

To hunt here requires stealth and subterfuge.

And living within the trees is a master of ambush.

A preying mantis.

Well camouflaged and lightning quick,

these insects are highly efficient predators.

But even they are outgunned.

A chameleon.

Its camouflage is exceptional because it can change its skin colour to match its surroundings.

Its eyes move independently to spot prey.

It creeps towards to its victim, until just in range.

Then it unleashes a super weapon.

Its tongue shoots out at 15 metres per second.

And not only hits, but grasps its target.

But few hunters are always successful.

For them a hunt is just one meal.

For prey, the stakes are higher.

It's life... or death.

As Antarctica moves from spring into summer, the inlets and bays, once choked with ice, become free.

And animals move in to feed.

These are crab eater seals.

They don't actually eat crabs, but krill, small shrimps that swarm in their billions in these waters.

Resting on a large ice floe, these crab eaters are safe.

But as soon as they enter the water, they are on their guard,

for good reason.

Killer whales.

Here in Antarctica, many killer whales prey only on fish.

But these whales are different, they specialise in hunting seals.

This seal swimming to open water is unaware of the danger heading his way.

Until now.

He's in real trouble. There is no escape unless he can hide behind this small piece of floating ice.

But he's been spotted and surrounded.

Now agility is his only chance.

He dodges for his life, staying as close as he can to the iceberg.

He's tiring.

And the whales tighten the circle, going for the kill.

But hunters don't always get their own way.

In the end, the seal's determination and skill, using

the ice for protection, kept him just out of reach.

And the whales move on.

Recently it's been observed that killer whales

are much more successful when hunting other types of seal.

Crabeaters like this put up too much of a fight.

For creatures living in the open ocean there is nowhere to hide from predators.

But there is safety in numbers.

One fish, however, has evolved a different escape tactic.

To leave the water completely, take to the air and fly!

After a huge effort to get airborne, flying fish

can glide 200 metres or so, to escape the predators chasing them.

Not all animals are hunters, many are vegetarians.

But the battle between animals and plants can also be intense.

Boa Vista, central Brazil.

This valley is peppered with strangely pitted rocks.

These are not natural formations but the legacy of a long struggle between one animal and one plant.

Brown-tufted capuchins, highly intelligent monkeys.

They spend their nights in the safety of caves,

emerging each morning to find food.

Down in the valley is a particular favourite.

A nut palm.

The palms produce huge seeds, but they have very strong shells

that protect them against attack from hungry animals.

For the capuchins this is a war of attrition.

They check which seed is the ripest, and the battle commences.

The first job is to tear the tough fibrous husk from the nut.

He doesn't try to crack the nut straight away,

but drops it to the ground.

He's learnt that a nut should be given a week or so drying in the sun.

These are ones he prepared earlier.

He taps them to see if they're ready.

This huge flat rock is his anvil.

And this is a hammer.

It's made of a different and much harder rock than the anvil.

Now something extraordinary happens.

The capuchins' use of these stone tools requires an exceptional level

of intelligence, planning and dexterity.

The nut finally cracks and exposes a rich, oily kernel.

Youngsters watch and imitate the adults, just as human toddlers do.

If they are to become independent,

they must learn to crack their own nuts.

But the learning process is long, with many frustrations.

They learn early on that to do a job properly,

you need the right tool.

It can take eight years for a capuchin to master this art

and overcome the palm's formidable defences.

But some plants have turned the tables and feed on animals.

This is a highly sophisticated trap. The bait,

sugary nectar around the rim of the disc.

The triggers, fine hairs, two of which have to be touched within 20 seconds of each other.

The victim, a fly which finds the colour and nectar irresistible.

One.

Two.

When triggered, the trap snaps shut so fast that the fly is imprisoned.

The Venus flytrap now slowly digests its victim.

Life's challenges are more than just finding food.

In every animal's life there comes a time when its mind turns to breeding.

One creature's approach is mind-boggling.

Malaysia.

This strange insect has been lying dormant on the forest floor.

Once safe in the trees, these males hide among the leaves and begin an extraordinary transformation.

One that will make the difference between fathering offspring or not.

He begins by gulping in air bubbles, forcing them up into his head.

He then pumps the bubbles into the stalks supporting his eyes,

just like blowing up a balloon.

And this is what earns these creatures their name,

the stalk-eyed fly.

A few final adjustments to straighten out any remaining creases

and he's ready for action.

They may look unwieldy, but eyes on stalks improve not only his ability

to spot predators, but they are key when it comes to winning females.

In the evening both males and females gather and the males begin to size one another up, eyeball to eyeball.

Having the widest eye span puts you at the top of the pecking order.

The eye stalks are not weapons, they're measuring sticks,

used to gauge how big, and so how strong, a male is.

But there's trouble if two top males have exactly the same eye width.

Then the contest descends into a brawl.

Defeated.

The winner. He now has the right to mate with all the females nearby.

The rather gentlemanly way stalk-eyed flies settle their differences over females is not the only way.

Some animals are much more violent.

It's the dry season in Zambia.

The lagoons are either baked dry, or the mud is so thick animals get stuck, with fatal consequences.

This male hippo has been living in one small lagoon, but as it dries, it's turning into a death trap.

Understandably, the females that once shared it with him have all left.

Even if he wants to, he can't stay much longer.

He needs water to keep cool and females to mate with.

And this is where they all are.

Almost all the hippos in the area are in what is left of the Luangwa River,

because it's the last place where there's still deep water.

This bend is controlled by an all-powerful male.

Since the drought many more females have joined his herd.

They are happy to live cheek by jowl, but any male who comes here

in the hope of mating must first defeat the overlord.

The wandering male arrives and has a decision to make - submit or fight.

Victory for the overlord.

His domination of his channel in the river remains and with it mating rights with the females.

The loser is alive, but is an outcast.

He retreats to another part of the river where it's so shallow that no females will follow.

His chance to father offspring is over for now.