Predators (2000) s01e04 Episode Script

A predator attacks.
Its prey defends.
Each makes life and death decisions.
Who will succeed? Who will fail? The outcome depends on strategy and the skill to survive.
A predator, totally focused on her objective.
The result, far from certain.
Success or failure? The only two outcomes for the lioness.
Many factors will influence the next few minutes.
Here she approaches from behind.
But this is exactly the place the zebra has most defense.
The lioness is kicked off as she leaps on to the zebra's hind quarters The advantage lost.
The lioness realizes that there is no option but to abandon the chase.
But there could have been a different outcome.
In exactly the same situation, a simply change of tactic makes all the difference.
This time, the lioness attacks from the side, making it harder for the zebra to kick her off balance.
She locks onto the shoulder, a vulnerable place, away from teeth and hooves.
And uses her weight and power to wrestle the victim to the ground.
Finding the right strategy is a complex task.
There are many factors to consider.
Is the prey too dangerous to attack? Is there enough cover to get close? When is the right time to charge? It's never simple, prey are always alert and defensive.
With so many variables, the lioness, like all predators will tend to take the easiest option or what seems to be the easiest option Picking on the young and more vulnerable is a good strategy.
If the lioness is lucky the herd will abandon the buffalo calf But even this ploy can back fire.
In a dramatic reversal fortune for the predator, the mother chooses to protect her young Now it's the lioness who could get hurt It could easily have been fatal.
Failure is a large part of a predator's life that is really an uneasy contest.
A simply misjudgment could loose a predator a meal or even its life.
A bed of mussels on the seashore.
An unlikely setting perhaps for one of the most awesome battles between predator and prey.
But believe it or not, a mussel is as dangerous to its predator as a buffalo to a lioness.
The predator is a dog whelk, a slow but determined killer.
It's a carnivorous snail that patrols the edge of the mussel bed, searching for a victim.
The battle between a mussel and a dog whelk has different options and different outcomes.
A mussel is far from being a powerless creature.
Their frilly mantles are full of sensors which pick up on danger approaching.
They can see changes in light and shade.
They even smell the whelk.
As it gets closer, they become agitated and their hearts race.
But they can't run away.
They're tied down with very strong threads called 'byssus' that make out what is commonly called the beard.
So the whelk doesn't need to hurry.
It spends three hours selecting the right sized victim.
About 25 millimeters is a good manageable size.
But the success of the whelk's strategy depends upon this The mussel's multipurpose foot is a glue dispenser and thread extruder, all in one.
When it finds a good spot, glands in the base pump out different substances.
First glue, then threads.
These threads are amazing they act like guy ropes anchoring the shell to any wet slippery surface.
They're the envy of science, no manmade glue has come close.
They are so effective at anchoring in rough water that huge beds form thousands of individuals bond together making them sitting targets for whelks But the whelk must attack in exactly the right place.
If it finds a suitable meal on the edge of the colony then there is nothing the victim can do.
It climbs aboard, well away from the foot and gets to work.
The whelk is a driller killer.
It scrapes the shell away with small hard teeth helped by a chemical softener the mussel's heart starts to beat faster and faster.
It takes a laborious two days to break through.
It then secrets digestive juices which slowly dissolve the mussel's body For a further two days, the whelk eats the mussel alive.
In the last few hours, the mussel has a series of heart attacks and dies.
The dog whelk moves away.
All that's left behind is a small hole.
But there is another scenario.
If the whelk goes into the middle of the colony, it loses its room to maneuver.
Then the mussel's foot takes on in a more sinister purpose Threads that can defeat a storm can easily tether a snail.
The whelk is trapped.
It can't escape.
It can't feed.
It will starve to death in the midst of its prey.
The enemy disabled the mussels can safely put away their weapons.
For many whelks, their hunting ground becomes their graveyard.
In the Arctic, where the sea is frozen The strategies of predator and prey are driven by sound.
A ringed seal listens intensely.
Its life depends on it.
Wind, creaking ice, waves, blowing snow the seal can distinguish them all.
Down here, it is safe, but the seal is a mammal and needs to breathe every ten minutes And its choice every ten minutes is to select a breathing hole which is safe.
Noises from above help it find its way to breaks in the ice.
The sounds underwater are best detected using these not ears, but whiskers.
At the base, are tiny crystals that pick up on vibrations in the water, just like our finger tips they need to be warm to work.
A thermal camera shows how hot a seal's face is compared to the rest of its body.
Warm blood is diverted to the face, even though the rest of the skin can be near freezing.
Even in these conditions, a seal's whiskers are ten times more sensitive than a cat's.
Underwater, sounds are useful for navigation.
But what the seal really needs to listen out for is this A polar bear pads silently over the ice, searching for a meal.
At low temperatures ice transmit sound very well.
Each step crushes the ice crystals, sound waves shoot through to the water below.
As long as the bear keeps moving, the seal knows where it is and can keep away.
The problem starts when the bear stops.
Is it standing right next to a breathing hole? The seal has no way of knowing.
A ringed seal can have as many as 12 holes in use at any one time.
But which is the dangerous one? The bear's best strategy is simply to choose a hole and be prepared for what could be a very long wait.
But it is worth the wait.
The fat from one seal will keep it going for a week.
Before it surfaces, a last check for danger because once it begins the ascent, it is committed.
It's too buoyant to change direction at the last minute.
Fortunately for the seal the bear chose the wrong hole.
But every week or so, it will strike lucky.
A change of season can transform a predator's choices and its tactics In the mountains of Queensland, Australia, lives another ambush specialist.
For most of the year, the python works alone.
It stalks its victims tracking them with smell, sight and heat sensing.
It will get by on one meal every few weeks.
The target won't know what hit it.
But once a year, a much more attractive option appears A cave fills up with a bounty that local snakes find it hard to resist A hundred thousand little bent-wing bats, all females and their babies roosting here until the young are independent.
Hanging on the roof, they are out of reach, so the snakes need a new technique Arriving at night, they jam their coils intt the rocks at the cave door.
Up to 15 snakes can be draped down the cliff, and they can be three meters long.
Then they stretch out across the entrance like living fishing rods.
The bats have to fly out of the cave to feed.
The cave entrance is narrow and the snakes, long.
The bats have to run the gauntlet of many waiting jaws.
The pythons have lightning reactions.
Each snake can catch up to 12 bats a night.
They eat enough in just one night to keep them going for months.
But only because they selected a different option and changed their strategy.
Strategy is the art of finding solutions to a problem.
Fish are very difficult to catch.
They have an astonishing range of skills to protect themselves.
They have excellent eyesight picking up the slightest variation in light and shade.
The tiniest vibrations in the water are detected by the lateral line.
A row of microscopic hairs that register changes in the pressure in the water.
Any disturbance triggers them to startle away.
They've got an acceleration that equal to naught to 90 miles per hour in 1/100 of a second.
Slow down nearly 200 times we can see the body flexing as the muscles propel it away from danger.
This is the fastest reflex of any animal.
But even these defenses have flaws.
On this one lake in Israel, three birds have evolved completely different ways of catching the same fish.
Three birds, three strategies, one prey.
First, the pied kingfisher, the largest bird in the world that can hover in still air.
At ten meters above the water surface, it knows it can't be seen by its prey To locate a fish, it has to keep its head perfectly still The tail is used to keep it stationary.
The wings beat at eight times a second.
This uses a lot of energy and the bird can't afford too many misses.
In half a second, it catches a fish, but it's far from easy.
To have any chance of success, it has to get the dive just right.
Once it's locked on to its prey, it begins a controlled descent.
At this point, it can still abort the attack if the fish has spotted it.
But once it's a couple of meters from the water, there is no turning back.
The fish must still be oblivious or it will have time to escape.
The next critical moment comes when the beak hits the water surface Here it's slowed down 200 times.
Although it's shaped like an arrow and hardly makes a ripple, the tip of the beak sends shockwaves through the water.
As the beak goes further in the waves travel further out, and are picked up by the sensitive hairs on the fish's body.
Now the kingfisher's success depends on how quickly the fish reacts Fish that escape react just 1/50 second faster than those that get caught.
The pied kingfishers win by beating the fish's reaction time.
But the second predator has a strategy which exploits another weakness in the fish's defenses.
The egret walks through the shallows deliberately scaring the fish with its feet.
Apparently not a good idea.
But it knows the fish tire quickly.
They can only swim at speed for a few centimeters at a time.
And they slow down just within range of the egret's long neck.
Using its razor-harp eyesight, it tracks the prey's escape but keeps its head poised in strike position.
At the instant of attack it flings the head forwards the beak hits the water at 70m/s.
specially shaped vertebrae and the s-shaped neck act as a pivot.
But despite the egret's specialized design and strategy, it only catches a fish 50% of the time.
Glare, waves, shimmer and distortion hide fish from topside hunters.
But the third predator sidesteps this problem.
Its strategy is to behave like a fish Cormorants specialize in underwater attack.
They are designed to move easily between air and water.
Their feet are webbed and set back on the body to help them swim and dive.
Special feathers let water in fast expelling air, so they can submerge quickly.
But a cormorant's greatest attribute is its eyes.
Above water, the pupil is small restricting the amount of light entering the eye.
A greater cormorant's eye shows how tiny the pupil is.
But a split-second after the head submerged, the pupil expands to let in more light and the lens change shape.
It sees clearly even in dark or cloudy water.
The chase is on.
Slowing their heart rate by half and reducing their need for oxygen by 90%.
Cormorants can stay underwater for minutes at a time.
They become target-seeking submarines The fish dart away but are soon exhausted.
The cormorant easily chases them down Their diving expertise allows the cormorants to go further out and chase larger fish where sometimes the rewards can be magnificent.
But a single predator pitting its strength and wits against a single prey isn't always the best strategy.
A lioness hunting alone, is successful only 30% of the time By joining forces, she can double her strike rate to 60% Outnumbered, it is more difficult for prey to use their skills and mobilize their defenses.
Many predators work together because a mass attack can tip the balance in their favor But prey also play the numbers game as we'll see in the next program.
A wolf pack wear down their prey Giant hornets on a raid Humpback whales coordinating their attack.
Army ants marauding through the rainforest.
But flocks of prey confuse predators And shoals can startle too.
Predators, uncovering the moments where life hangs in the balance.