This is Shetland in spring.
Around these cliffs live pirates that have turned hunters.
Every year, sea-birds return here to breed.
On the clifftops, where there's turf, puffins dig their nest holes.
Sitting beside them, they're relatively safe,
for if danger threatens, they can duck inside their hole.
It's when they're in the air that they're really vulnerable.
Here the greater black-backed gull is on patrol.
It's a huge bird, substantially bigger then the lesser black-back.
It has a wingspan of over five feet
and the manoeuvrability of a fighter aircraft.
The puffins, whose wings and feet also serve in swimming and diving,
are much less agile in the air.
Flying in flocks reduces an individual's risk,
but that's not always possible.
With the puffin almost swallowed, the gull has at last got a meal.
Or has it?
The murdering robber has been robbed.
There are other animals that spend most of their lives at sea
and come to the land each year to breed: seals and sea lions.
These are South American sea lions off the coast of Patagonia.
They can't give birth while swimming like whales and dolphins do.
Instead they have to come ashore,
and here, in dense groups, moving awkwardly between land and sea,
they're a great temptation to any hunter that can reach them.
Their nursery beach seems secure.
The landward side has steep cliffs.
On the other side the beach is protected by the sea.
But the sea itself can harbour enemies.
A killer whale, thirty feet long, eight tons in weight.
Every year the same group of a dozen of them assemble off the sea lion nursery to hunt.
For sea lions to venture into deep water here is very dangerous.
It's much safer to stay in the shallows if they can.
In some places, channels enable the whales to get close to the beach.
Those are the danger spots.
To get off the beach, the killer has to thrash its body.
No other whale deliberately beaches itself like this
or has perfected this method of getting back to the sea.
As long as they stay up the beach, you might think they'd be safe,
but the hungry whales are very daring.
This savage beating may be to separate hide from flesh.
But often the successful hunter takes its victim out to sea
without even killing it.
And there, it plays with its catch as if it were exalting in triumph.
To get all the food it needs,
a killer whale must catch at least three sea lion pups a day.
And every day in the breeding season,
this group of skilled, highly intelligent hunters do just that.
Slugs, you might think, are hardly a challenge to a hunter,
but few things want to hunt them.
This, however, is one: the thirst snake.
Its hunting technique is simplicity itself.
The slug's slime, which makes it so unappetising to most predators,
provides the trail which the thirst snake follows.
But swallowing such a slimy mouthful is not easy.
The snake manages it by dislocating its lower jaw
and twisting it forward so it snags the slug with its teeth.
Then a yawn puts the lower jaw back into its position.
Not all the hunted give in so easily.
Many have ways of deterring hunters that try to make a meal of them.
An American opossum may think this frog will make an easy mouthful.
It's quite wrong.
First, the frog inflates its lungs
so it looks as big and formidable as possible.
Then it lets off a most surprising alarm.
(LOUD WAILING SCREECH)
The whole performance is more than enough to put off the opossum.
The tomato frog has a rather more damaging defence.
When threatened, it exudes a milky poison from glands in its skin
that would make any aggressor very sick indeed.
A potent and near perfect deterrent, you might think.
The problem of having poison as a defence is, if you're not careful,
by the time you've convinced your attacker you're not worth eating,
it has either mauled you or killed you.
So many animals that have poison
advertise the fact before it's necessary to use it.
Look, for example, at this little creature.
It's a spotted skunk.
Like the bigger striped skunk that also lives in the southern USA,
its tail glands can squirt a jet of liquid with a smell so appalling
that it can make you sick, so you should treat it with caution.
Now I'm going to press my luck a bit...
It doesn't want to waste its ammunition unnecessarily,
so it gives fair warning.
As eloquent a display of gymnastics as you could imagine
with which to back up its warning spots and stripes.
How better could you call attention to the spray gun beneath your tail?
I'm not going to get any closer, because I'll get sprayed.
And I don't want to risk that!
Salamanders also put on gymnastic displays to declare they have chemical weapons.
In their case, it's in their skin.
Having jerked convulsively into an extraordinary contortion,
they stay there, transfixed.
Its warning colours are on its belly,
so when danger threatens it throws itself on its back.
This one has its poison in a line of sacs along its flanks,
released by the drastic method of sticking its ribs through its skin,
tearing them open.
But instead of drawing attention to yourself,
you can get protection by doing the opposite, by concealing yourself.
A stick? No, an insect.
This is its head with the front legs stretched up beside it.
You really only have a chance of recognising it when it walks.
A band of moss, perhaps?
No, another insect.
But lying so flat against the twig that it seems almost a part of it.
Only its antenna, lifted above the twig,
and a slight adjustment of its position gives the game away.
This insect mimics living leaves even down to tiny details.
Green flanges sprout from its legs.
Few of those hunted among leaves can have a better concealment.
But two can play at that game.
What could look more innocent than this orchid,
blooming in the half-light of the Malaysian rainforest?
Its white flowers are bright and proclaim the sweetness of its nectar,
attracting a lot of insects.
But even in such a lovely thing as this danger can lurk.
Sitting on it, exactly matching the colour and texture of the petals
is a mantis.
It's facing left, with its abdomen up on the right,
and it's waiting motionless for the butterfly.
Sometimes mimicry is used not to conceal but to deceive and confuse.
The eyespots of this caterpillar give it an almost snake-like appearance.
These tentacles that give off a nasty smell heighten that resemblance.
But could this really be an imitation of a snake's forked tongue?
Could the caterpillar be mistaken for a snake
when it's only a couple of inches long?
We don't know and can only guess.
And this is an even greater mystery.
It's a frog, and one that like most frogs is hunted by snakes.
The centres of the eyespots carry poison glands,
but they could hardly have deterred the snake.
It can't see them from the front.
So how does having a face on its bottom protect the frog?
No one knows.
But there's one animal against which none of these techniques works.
One hunter which is invariably successful.
This one.
Beneath this log is an immense ball of ants.
Its surface is a lacy veil,
formed by individuals clinging to one another's legs.
There are about three quarters of a million of them.
They are army ants, and this is their bivouac.
In the morning, a raiding force of workers escorted by bigger soldiers
leaves the bivouac.
They're almost blind, but they follow a scent trail laid down by scouts who are foraging ahead.
Few things are safe from them.
Not even a giant spider.
The sting of a scorpion is useless against such tiny aggressors.
They're too small to hit and too numerous.
A wasps' nest is a major prize.
The adult wasps, even though they have powerful stings, can't repel them,
and they watch helplessly as their colony is pillaged.
The fat grubs are hauled from their cells,
butchered and carried off.
Bigger victims are cut up for easier transport,
and carried to the queen and the workers waiting in the bivouac.
A caterpillar's camouflage didn't save it.
In some places, the soldiers form living bridges across which the porters run.
After two weeks in camp,
the numerous eggs the queen has been laying are hatching.
The grubs need feeding and the entire army once more starts to march.
The workers carry the baby grubs.
Soldiers, huge jaws agape,
guard the sides of the route.
The army marches across new hunting grounds,
making temporary camps each night,
until, after about two weeks, it bivouacs and repeats the whole cycle.
Army ants, like most predators, are highly specialised hunters.
Only a few animals are able to mix hunting with other ways of gathering food.
One of them lives here, in the forests of West Africa.
Chimpanzees.
(WHISPERING) You don't normally think of them as hunters.
More as gentle vegetarians,
munching fruit and picking leaves.
But if you follow them in their true home,
these forests in West Africa,
you discover that they are hunters.
What's more, they hunt in teams,
and have a more complex strategy than any other hunting animal,
except...
except, of course...
..man.
And one of the hunters,
the experienced male,
is sitting right there.
This is the time they hunt: the wet season.
Their regular prey are monkeys, but they're very selective.
A diana monkey, a big species,
and one they seldom tackle.
A spot-nosed monkey.
Red colobus.
They're better jumpers than chimps and can go onto thinner branches.
In theory a chimp can't catch them.
The only way is to work as a team,
and there are six experienced males in this group of sixty
who regularly do so.
This is one of them.
From his purposeful walk, it's clear the search for prey has started.
The other members of the team are not far away.
They've been following the monkeys for twenty minutes,
looking for an opportunity.
The technique they'll almost certainly use
is that one of them will be driving the colobus ahead of them.
Then there'll be others up on either side, the blockers,
who make no attempt to catch them.
Then there are chasers, who try to grab the monkey.
Finally, there's one male who will go ahead and ambush it,
so bringing the whole trap closed.
The monkeys are now getting alarmed.
A driver's going up to drive them towards an area where they're more easily trapped.
That's one of the blockers that's quietly come ahead of the colobus.
He's halfway up the tree now.
He's deliberately making himself conspicuous.
It looks like they're all in position.
The drivers and blockers have gone up,
and the one who'll make the ambush and close the ring has gone up, too.
The colobus will be very lucky if they escape now.
(DIN OF SCREECHING)
They've got one!
The hunters are tearing it apart.
Everyone, the hunters in the trees and the spectators,
are screaming with excitement.
Now the kill is brought down,
so that the females and others can share it.
And there's the reward for that long chase,
the divided body of a colobus monkey.
These bloodstained faces...
..may well horrify us,
but we might also see in them
the face of our long-distant hunting ancestors.
And if we are appalled by that mob violence and bloodlust,
we might also see in that, too, perhaps,
the origins of the teamwork that have, in the end,
brought human beings many of their greatest triumphs.
Rajasthan, central India.
It's the middle of the morning, the day is warming up,
and the animal community is in a relaxed mood.
The samba deer are cooling themselves in the lake,
looking for a bit of greenery to nibble
and tolerantly taking the egrets for a ride.
The egrets are finding a little to eat -
an insect, perhaps, picked out of the deer's coat.
Nature isn't always red in tooth and claw.
Different kinds of animals often get on well with one another.
In the trees, langur monkeys are finishing their morning meal of leaves.
They're fussy, untidy feeders, and drop a lot of the leaves,
either by accident or because they don't fancy those particular ones.
And that suits the spotted deer.
In the dry season, the ground is parched
and greenery worth eating very scarce.
Even a small fragment of vegetation fallen from above is worth having.
And the deer follow the monkeys,
picking up leaves that by themselves they couldn't reach.
The monkeys benefit from the presence of the deer.
They sometimes come down to the ground,
and there they're vulnerable.
The deer have a keener sense of smell than the monkeys,
and may detect dangers the monkeys can't see.
And if they do, they will stamp a warning.
This association is little more than a passing convenience.
Other animal relationships are more permanent.
This species of goby, for example, that inhabits coral reefs,
nearly always lives with a shrimp.
The two regularly live together, sharing the same hole.
But the goby plays no part in making it. It's dug entirely by the shrimp.
The shrimp in fact seems to be a compulsive excavator,
never content with its home,
always carrying out improvements and digging extensions.
And the goby doesn't help.
In fact, if anything, it gets in the way.
But it's an essential companion for the shrimp,
for this species of shrimp is virtually blind.
The goby, on the other hand, has excellent eyesight
and is always on the alert.
The shrimp, as it works, keeps in touch - literally -
by continually flicking its long antenna over the fish
to make sure it's still there.
If the goby is out of the burrow,
the shrimp knows that it's safe to carry on working.
The goby is always on the lookout for something to eat
and may have to make little excursions to get it.
A tiny, edible morsel that floated by.
Even while it's feeding, the shrimp's antenna is still in touch with it.
Danger...and when the watchman retreats to safety,
so does the shrimp.
The goby, having fed, seems content to remain in the hole.
Why expose yourself to danger unnecessarily?
But the shrimp is keen to work and appears to be hustling the goby,
as though to persuade it to go out again.
The shrimp collects its food from a patch of alga
that grows beside the burrow entrance.
It knows just where that is, so it can nip across quickly for food
with the minimum of risk.
All is well, as long as the shrimp keeps in touch with the goby.
If it ventures away, then there can be trouble.
That was an anemone it blundered into, and it beats a retreat.
For a moment it seems lost.
Then the goby comes over, and contact is re-established.
The partners are together again, and all is well.
So two very different animals operate a partnership.
The blind landlord provides the accommodation,
and the tenant provides a guidance service.
A hermit crab.
And a small octopus.
Hermit crabs are its favourite food.
The crab relies for protection on a discarded shell,
in which it's tucked its rear end.
In the centre of those writhing arms, it has a powerful beak,
with which it can drag the crab from its shell.
And that's the end of the crab, shell or no shell!
But this species of hermit crab recruits a bodyguard.
Anemones have stings in their tentacles -
stings that are strong enough to repel an octopus.
Since the crab wanders about a great deal, its bodyguard, to be any good,
has to travel with it.
It's not easy to unstick an anemone from a rock,
but the crab knows the trick.
You have to tickle it around the edge of its bottom!
You can tell the anemone isn't alarmed by this procedure,
because it hasn't closed up and is still waving its tentacles.
That makes three guardian anemones on the crab's shell.
But is that enough to give it protection?
The octopus is not sure.
No, it's not worth it.
So the crab has its bodyguards,
and its bodyguards, for wages, will get bits and pieces that float by
when the crab chews up its meals.
It's not always easy to decide in these partnerships
which is exploiting which.
The balance of advantage is often delicate.
Take, for example, these ants in Australia.
They are extremely ferocious and will normally rip apart any caterpillar.
But see how they're treating this one.
The caterpillar has on its back a number of nipples
which apparently fascinate the ants.
One near its back end, when stimulated by an ant,
produces a drop of liquid, honeydew, which the ant drinks.
As the caterpillar grazes on leaves, the ants keep continuous guard,
threatening anything that comes near, so that even birds don't attack it.
The caterpillar must make sure
the ants don't forget what kind of caterpillar it is.
If they think it's any other kind, they'll eat it.
So the caterpillar occasionally makes a characteristic buzzing vibration.
Not only that, but on either side of the nipple there are two others.
From these sprout little tentacles,
which release a pheromone, a kind of perfume,
that keeps the ants happy and unaggressive.
The tree ants build nests as big as footballs
from the growing leaves of the tree.
First, a team bridges two leaves and pulls them together.
Others carry grubs that produce a sticky silk.
By passing the grubs back and forth,
they weave a fabric that holds the two leaves in place.
They're making a shelter for their precious caterpillar.
When it's complete, they guide the caterpillar into it.
Once in its shed, it'll be safe for the night.
The ants look after it like farmers looking after a dairy cow.
At this stage in the history of their relationship,
neither ants nor caterpillar seems to have the advantage.
But this same species of ferocious stinging ant
is also partners with a different species of caterpillar,
and there the result seems very different.
This one has a glossy, horny shield on its back,
and it, entirely of its own accord, marches right into the ants' nest.
It is in no way deterred by the ants' threatening postures
and sprays of formic acid.
No matter what the ants do, they can't stop it.
Deeper and deeper it goes, through the corridors of sewn leaves,
into the heart of the nest.
With the intruder within the nursery, the workers become totally confused.
Some try to carry off the grubs to safety elsewhere.
But they can't do it quickly enough.
The caterpillar snatches a grub, pulls it under the shield,
and then, secure beneath its armour, slowly eats it.
After several weeks, the caterpillars have eaten all they need
to grow to their full size.
Deep in the heart of the nest,
they're ready to shed their armour and turn into butterflies.
But how can a butterfly get through the ant soldiers?
Now, surely, they'll have a chance for revenge.
Slowly, the insect hauls itself out of its horny armour.
But it's a strange sort of butterfly that emerges.
It's covered in scales so slippery
the ants can't get a proper grip on them.
Those that do manage to bite get their jaws covered in fluff
that they clearly find intensely irritating.
So, at last, the murderous lodger goes free.
Ants and caterpillars, like crabs and anemones,
are about the same size.
If the lodger is very much smaller than its landlord,
then it tends to live not so much with it as on it.
Those monkeys over there, for example.
They've got a number of tiny passengers.
Like most mammals with hairy coats, they've got fleas.
And when fleas bite and start sucking blood, they itch.
It's not only mammals that have lodgers in their fur.
As night falls in North America, a moth visits a milkweed flower.
Dipping its long thread-like tongue into the heart of the blossoms,
it sips the nectar.
This moth is infested with mites.
Its ear, a tiny hole in the side of its head,
has become the home of a whole colony of them.
The milkweed is a staging post for the mites,
and a new colonist awaits on the flower itself.
While the moth drinks, the mite crawls up its tongue.
Once on the moth's head, it knows just which direction to take
through the jungle of fur to reach the ear.