The Trials of Life (1990) s01e08 Episode Script

When things are scarce in this harsh world, you may have to fight to get your fair share of them.
In this case, it's food, meat.
But you may have to fight, too, to get the best available mate that's around or territory which will support you and your family.
So the ability to fight is needed by animals of all kinds.
Even sea anemones fight on occasion.
This group, catching floating particles of food with their tentacles, is harmonious enough, for these individuals are all sisters, budded off one from the other and, therefore, genetically identical.
This, however, is a stranger.
The residents can detect chemically that these tentacles are no relations of theirs.
Someone else is clambering onto their stone, seeking their feeding space.
This is war.
The battle is difficult for us to recognise, for anemones work on a rather slower time-scale than ourselves, but speed things up and the fight becomes obvious.
The lashing tentacles are armed with stings.
The resident anemones have had enough and off they go.
Male strawberry frogs in the jungles of Costa Rica, when breeding time comes, fight over territory.
They wrestle.
(C0NSTANT CHIRPING CR0AKS) They call throughout the contest.
If one stops, it's a sign that he's given in.
If he continues to call, even if he's retreating, his opponent will continue to pursue him and take him on for another round.
These bouts may go on for as long as half an hour.
In fact, the result is pretty well a foregone conclusion.
Unless the intruder is very much bigger, the resident, the one who was here first, nearly always wins.
The loser will hop off to find an unoccupied square yard of forest floor, and no great damage has been done to either contestant.
But many animals can injure one another only too easily.
The hummingbird, like many other animals, feeds with a device that can also be used as a weapon.
Here in Trinidad, hummingbirds defend patches of flowers full of nectar on which they feed.
And an owner threatens an intruder by displaying brilliant colours.
But make no mistake, these ritualised threats are backed up with real force.
Watch what happens if an intruder appears in this defended patch and stays put, as this little stuffed hummingbird presumably will do.
First, the threats.
Spreading the tail and angling the brilliantly coloured reflective feathers on the throat and the head so that they catch the light.
Usually, this is quite enough to frighten off a rival.
But it's not working in this case.
So now he decides to use force.
And still his rival won't go.
Maybe it's not a rival.
Maybe it's a particularly stoical female eager to mate.
So he tries that.
But with such an unresponsive partner, it's difficult to find the right place to do so.
Another hummingbird sees what's going on and interrupts him.
So another intruder has to be seen off.
Then he returns to his first problem.
The needle-sharp beak, which he normally uses to thrust into a flower for nectar, he now wields like a murderous stiletto.
It's an impressive demonstration of what can happen if an opponent doesn't give up.
Egrets.
Their beaks really are designed for killing.
They're spears for stabbing.
These quarrels are over roosting places.
The birds have spent the day away feeding, but now they've returned to a tree where they can spend the night in the safety that comes from numbers.
But some perches are better than others.
No one wants the outside position where they are at greatest risk from predators.
So again they squabble and again a tool for feeding has become a weapon for aggression, but in the event, in spite of all the noise and commotion, few pecks actually land.
These, too, could give a nasty nip.
The biting jaws of a rove beetle.
It uses them to snatch flies.
But the smell of the object that attracts those flies, monkey dung, also attracts rivals.
And then those jaws have a different use.
Before coming to blows, the beetles also threaten one another.
Not with colour like hummingbirds, but by an aggressive smell which they discharge from their abdomen.
And once again, threat is all that was necessary.
Better to not risk injury from those powerful jaws if that can be avoided.
There will be some more dung somewhere.
This tiny pool in a tree stump in Panama is the nursery of another powerfully armed insect, a damselfly larva.
Its weapons are jaws that shoot out from beneath the head.
Its threats - distinctively patterned, leaf-shaped gills on the end of its abdomen.
Its opponent - any other damselfly larva that comes near.
There's not enough food in this part of the pool for two.
If they come to blows, the loser will be killed and eaten.
But there's enough room here for them to separate, and both survive.
The Midas cichlid of Central America is not, in truth, well armed at all.
It feeds by picking off bits and pieces here and there and it has no teeth to speak of.
But its mouth can give it a hold for a trial of strength.
As with frogs, if the pair are equally matched, and these are, it will be the territory owner who wins.
Pincers - obviously useful for both feeding and fighting, but the pistol shrimp has one much larger than the other and it uses it in a particularly damaging way.
The moveable side claw cracks down on the palm with such force that the noise can stun a passing fish or an opponent.
(L0UD SNAP) The shock knocks him senseless.
But one crustacean, however, is even more powerfully armed.
The mantis shrimp lives in burrows.
This female is guarding eggs and won't abandon them or her hole without a fight.
0utside, a male looking for a home.
Both animals can deliver a blow with their forelegs that can crack the shell of their prey or an opponent.
If they're going to argue, they must be very careful.
She threatens him by displaying the bold pattern on her forelegs.
But he's not intimidated.
He badly needs a hole to shelter from predators.
He shields himself with his tail, which has specially thick armour.
That foreleg, enlarged at its end into a fearsome club, is the weapon that does the damage.
He's won.
She's lost her eggs and her home.
Considering the force of the blows they've exchanged, she's lucky not to have lost her life as well.
But male and female must meet sometime, even among mantis shrimps, if they're to breed.
0nce again, it's the female who is in possession of a burrow.
And she is not going to surrender it willingly to anyone else.
He has to convince her that he has something else in mind.
She blocks the entrance with her armoured tail.
He tickles it, reassuring her about his intentions.
Wafting his scent into the hole also helps to convince her.
A quick coupling, and it's all over.
That, in mantis shrimp terms, was comparatively easy.
This male, on the same mission, is rather more apprehensive.
She is, after all, bigger than he is, and she could crack him open with a single punch.
Understandably, he shields himself from such a disaster.
But faint hearts never did win fair ladies.
She has no use for him.
She's not receiving visitors today.
If food-gathering weapons are lethal, their use is usually prohibited in fights between rivals.
These wasps have extremely powerful stings.
They lay their eggs in burrows in the ground and stock them with caterpillars which will serve as food for their developing young.
Having found one, a female wasp paralyses it with her sting.
But caterpillars are in short supply and others have seen it.
Yet no matter how vigorous the dispute, the wasps do not use their stings on one another.
It's not worth risking death for one small caterpillar.
The winner carries off her prize.
A quick check belowand she's lost it.
If rattlesnakes used their food-collecting weapons in their fights, they might kill one another, for they have one of the most lethal of all venoms.
Yet they, too, have their rivalries.
Males meeting in the autumn, at the start of the breeding season, have arguments to settle.
But their fights have rules.
The aim, it seems, is not to bite your opponent, but to slam him to the ground.
Wolves, too, could kill one another just as they can kill a deer.
But most of their disputes are settled by a complex series of gestures.
Initial threats are made by lifting the lips to expose the weapons they could use: their teeth.
Even when tempers flare, there is still restraint.
Jaws may grip throats and heads, but they don't bite.
Disputes among wolves, as among most dogs and cats, are largely a matter of threatening snarls.
It's hardly surprising that meat eaters, which have, by their very nature, to be ferocious and aggressive, should also be a bit quarrelsome on occasion.
But you might think that, by contrast, grass eaters, like these zebras, would be peaceable, gentle creatures.
But, actually, the male stallion zebra, on occasions, has to fight his own kind.
Look at this lot.
These are young males.
They're just sparring, practising for the crucial duels they'll have to fight as adults.
Then their fights will determine their success as breeders.
Now they're largely a matter of high spirits.
Since zebras don't kill other animals for food, they don't have death-dealing stings and fangs.
Their only weapons are their hooves and their relatively short, blunt teeth.
So, paradoxically, their fights can be very vigorous and involve a great deal of barging and nipping.
An adult breeding stallion fights in a much more determined way.
He is constantly having to chase off other males who are seeking to mate with his mares.
His short teeth can't give him a proper grip on an opponent's flank.
The only place he can deliver a decent bite is on the neck or the legs.
And the best way to protect your legs if things get rough is to sit on them.
A retreating loser can still deliver a powerful kick in the face, so the chase isn't continued for long.
And, in any case, the victor won't want to go too far from his mares in case another stallion gallops in while he's away.
Giraffes have no teeth at all in the front of the upper jaw, so they could hardly give a devastating bite even if they wanted to.
Instead, they fight with their necks.
Even here there is restraint.
A giraffe's kick can disembowel a lion.
But rival giraffes never kick one another.
They just use their heads like sledgehammers.
Gorillas may look ferocious, but they're usually peaceable creatures.
They, too, are entirely vegetarian and their teeth are hardly bigger than is necessary to rip bamboo apart.
The babies spend most of their time not quarrelling, but playing amiably with one another.
That, however, is a threat, a warning to a nearby group that this feeding ground is occupied.
A frightening charge is usually enough to make any intruder retreat without the need for assault and battery.
The young animals continue to play, even when they are almost fully grown.
But when you are as big and as strong as this, even minor disagreements can become a bit rough and things may get out of hand.
(L0UD SHRIEKS) And that's a sure sign of real fright.
So best to back off showing your teeth in an attempt to retain what's left of your pride and status.
Langurs, like gorillas, are also strict vegetarians, though you might not think so looking at these faces.
After all, you don't need huge canine teeth to masticate leaves or munch fruit.
These, however, are all males.
The females are much smaller animals and have no such fearsome fangs.
The enlarged teeth and greater body size of the males are clear indications that these animals are fighters and that they fight over females.
Even so, their formidable teeth are used much more for making noisy, grinding threats than delivering bites.
Langurs are not the only quarrelsome vegetarians to have developed their bodies in this way.
Hippos gather their vegetation with their leathery lips and then grind it to pulp with huge molars at the back of the mouth.
The tusk-like teeth in the front of the mouth, which this baby has yet to develop and which its mother already possesses, are used almost entirely in arguments between one another.
The bulls have even more spectacular tusks.
They yawn not because they're tired, but to display these weapons.
And if rivals don't take proper notice, they'll use them.
There's really little point in risking injury if the result of a fight is predictable, so assessing the strength of your rival brings benefit all round.
These Malaysian flies, roosting on hanging rootlets, have developed a very precise way of doing that to within a fraction of a millimetre.
Their eyes are at the end of stalks that stick out sideways from their heads.
They threaten with their forelegs.
But the crucial factor that decides whether they will fight is the distance apart of their eyes.
Rival males square up head to head.
A bigger eye span indicates a bigger body and, therefore, greater strength.
If a fly discovers that it's outgunned, it will back away.
These, however, have established that they are equally matched.
Now there will have to be a joust to get a settlement.
(HIGH-PITCHED CHIRPING) Field crickets make their judgments largely by sound.
They call by rubbing their wing cases together.
After arguing so loudly and so long, the briefest contact is enough to settle things.
Size of claw is the criterion used by these little mud crabs.
They quarrel over the ownership of a burrow.
And when one is convinced that its rival is bigger, then that's that.
The biggest weapons of all are developed by males who battle not over burrows, nor over food, but directly over females, as these bull elephants are doing.
If success in such battles brings the ability to mate with many females, to the exclusion of all other males who are less well-armed, then male weapons, over many generations, will become enormous, and the battles in which they are used violent in the extreme.
Exactly the same process that turned elephants' teeth into tusks has created the armaments of the stag beetle.
Their mandibles are so large that they can no longer be used for feeding, only for fighting.
Beetle fighting technique doesn't just involve charging or pushing.
Instead, each tries to prise his opponent from his footholds and hurl him aside.
The Hercules beetle is one of the biggest of all insects.
It, too, aims to lift and throw, but its weapons are rather different.
Instead of enlarging its mandibles, this beetle has grown a huge, forward-pointing horn on the back of its neck.
This engages with another curving upwards from the front of the head which is moveable, so the two can be used as pincers.
Few animals, in proportion to their body size, have more specialised and spectacular weapons than these five-inch monsters.
That looks like the decisive throw.
But no! Flies, too, develop grappling irons on their heads.
These are antler flies from Australia.
The rules of their fights demand that one tries to make the other topple.
A female approaches.
She has no horns.
A rival male tries to intervene, but is chased off.
Having won, he takes his reward and guards the female while she lays the eggs that he has fertilised.
A male ibex is on watch in the deserts of the Middle East.
It's the beginning of the breeding season.
Groups of females are scouring the mountainside, searching for a few leaves to eat.
The males, however, are seeking out one another.
Who is going to rule in these mountains? First, a cautious assessment.
This, impressive though it seems, is still merely a measurement of each other's strength.
If one is less strong, there is still time for discretion to be the better part of valour.
But if both decide they have a chance of winning, then battle begins.
This is a dangerous country in which to fight.
Sometimes a losing animal is killed by being forced over a cliff.
A contestant may be so badly injured, he never recovers.
But when the arms race between males has equipped rivals with weapons of this size, that is the risk you must take if you are to perpetuate your genes.
This is the biggest of all these kinds of weapons.
It's the antler of an Alaskan bull moose.
Together with its partner, it can have a spread of seven feet and weigh seventy pounds.
It's so heavy and cumbersome that after the battles are over, the bull moose sheds them.
It's such an impressive demonstration of strength that its mere appearance can deter a young bull.
If it comes to a fight, these forward-pointing spikes are used to blind an opponent or rip a wound in its flank, this broad palm to parry thrusts from an enemy and these spikes here to act as grappling irons, so that when the horns become interlocked, the contest becomes one of sheer physical strength.
During these battles, the antlers are often damaged, as this one has been there and there, but that doesn't matter because next year new antlers are grown bigger than ever.
This dominant bull has claimed half a dozen cows.
A young, ambitious male approaches the harem.
The resident bull keeps an eye on him.
A short charge - a warning.
It's enough to see him off for now, but the young stranger is persistent and continues to harass the females, attempting to isolate one.
The lord of the harem thrashes the bushes, drawing attention to his huge antlers, warning the young bull not to mess with him or his females.
This magnificent bull has got a radio collar on him, so we know a lot about him.
The collar was put on just over three years ago and already, at that time, he was king of this part of the mountains with a group of about half a dozen females.
He's kept that group with him for the past three years and been mating with them and this is his fourth season.
Bulls stand little chance of becoming dominant until they're about eight and they seldom live for more than 12 or 13 years, so this almost certainly is his last year as king.
If he wants to mate with those cows again this year, he's going to have to fight for them.
The battle is over, but at great cost to both sides.
The loser's antlers are badly damaged.
The following day, the king himself has collapsed.
Within a few hours, he will be dead.
His victories live on in the multitude of foals he fathered during his reign and his sons may develop antlers as big or even bigger than his precisely because he was their father.
But even when the genetic arms race leads to such an escalation of weaponry, most disputes may still be settled without violence.
Gazelles also have formidable armaments.
A stab from their horns could be lethal.
Yet the mood among the bucks is very different from among the moose.
Actual battles are relatively infrequent.
Rival Grant's gazelles assess one another's strengths with such care and reserve that a casual eye might not even recognise that this graceful gavotte has anything to do with conflict.
They turn and nod.
They resume their parallel walk.
This elegant ritualised parade is enough to convince most of the bucks in most of their disputes which of them is the victor.
No conflict could be more restrained.
But even among those animals who roar and snarl and brandish their weapons, most confrontations are settled with a similar lack of violence.
Risking injury is the final resort.
Restraint generally pays.