Underwater Universe (2011) s01e02 Episode Script
Predators of the Deep
Deadly underwater predators.
Hunters of the deep.
And he just shook me like a rag doll.
There is nothing a human can do to combat a 4,000 pound animal.
Since the dawn of life, they've ruled their universe.
If you were around for tens of millions of years, you would be good at what you did, too.
But the balance of power is shifting.
Classic killers are being pushed down the deep's most deadly list as others move up.
You don't really know how far away they are until they hit you.
Which will be the new number one, and why? Countdown to the deadliest predator in the underwater universe.
Underwater Universe 1x02 Predators of the Deep 3.
5 billion years ago, Earth's earliest life forms are born in the underwater universe single-celled organisms that evolve to produce energy through photosynthesis.
In return, they produce oxygen, sparking the evolution of life on Earth.
Over hundreds of millions of years, the deep becomes the breeding ground for the deadliest predators on Earth.
Predators in the ocean are historic and epic compared to what we have on land.
If you look at amazing creatures that live today, the ocean takes the cake.
Today's oceans are filled with predators that can kill a human being in a matter of seconds.
Five top the list.
Five animals that no thinking human should tangle with.
Which one is responsible for the greatest number of human fatalities in the last five years? Human beings have always been afraid of big scary things in the ocean.
Big scary things evolve in the ocean because a predator takes hold of a particular niche and is able to exploit it so well that it can grow huge.
And of course it exploits it by developing teeth.
Many of the top predators of the past use the power of their size and a bone-crunching bite to kill their prey.
The same is true today.
[Gasps.]
It's coming right toward us, Michael.
As far as an animal that I wouldn't want to swim with, Orca Whales are terrifying.
Number five in the countdown to the underwater predator deadliest to man is the Orca.
Also known as the killer whale.
12,000 pounds.
30 feet long.
These marine mammals are apex predators.
Hunted by no other animal.
They belong to a suborder of whales called "toothed whales.
" Fierce hunters, equipped with massive jaws and teeth that curve inward.
They can latch onto any prey.
From fish, to seals, to whales almost twice their size.
Killer whales are the most widely distributed large mammals in the world.
They live anywhere they want to.
They live in the arctic, the antarctic, the tropics; they live everywhere.
In Antarctica, they've devised a cunning way to rock seals off ice sheets.
To do it, they work in groups.
They have a complex family structure.
They communicate with one another when they're hunting, when they're diving.
Occasionally, whales have used their intelligence and sophisticated hunting techniques to take on humans.
[Indistinct chatter.]
In the coastal town of Falmouth, England, in the local maritime museum, three brothers examine the tiny dinghy that saved their lives.
Do you remember how that got rigged? It's a stark reminder of a brutal confrontation with a pod of killer whales.
In 1968, their father, Navy veteran Doughal Robertson, is a struggling farmer in rural England.
Douglas, the eldest son, is 14.
Twin brothers Sandy and Neil are nine.
We had no idea what sailing in a boat at sea was like.
And Doughal used to talk about it second nature.
And one day Neil said, "well, daddy's a sailor; Why don't we sail 'round the world?" And mother said, isn't that a marvelous idea? Well, no, she said, "that's a wonderful idea.
" A wonderful idea.
Whatever.
And that was it.
The seed of an idea is sown.
In 1970, their father sells the family farm and buys a sturdy 43 foot wooden sailboat called "the Lucette.
" A year and a half later, the Robertsons are 200 miles southwest of the Galapagos Islands, in the same area where back in 1820, a close relative of killer whales, a sperm whale, turns and charges a whaling ship called "The Essex".
An eyewitness calls it an act of revenge on the men who attacked the whales first.
The 238 ton ship is smashed in two and sinks, inspiring the great American novel "Moby Dick".
A century later in the very same waters, the Robertson family starts another day onboard "The Lucette".
12-year-old Sandy has the morning watch.
Off on the starboard bow, quite a long way, we saw whales.
And we didn't take any notice of it because we'd gotten quite used to them.
But these whales are anything but friendly.
The first indication I had was an almighty crash.
Bang.
Bang bang.
That's how the strikes came.
And they were so severe that they lifted, bloody lifted "The Lucette" out of the water by maybe a foot.
One 12,000 pound whale, traveling at 15 miles per hour has the impact of a wrecking ball.
My cup of tea left the boat up in the air like that and then came back down again.
And as I looked over the side, there was this huge killer whale.
I knew that was an attack, because the damage, it was just a big hole in the boat.
Dad was up to his knees in water.
And then he said, "abandon ship.
" And I said to him, "abandon ship to where?" We're in the middle of the Pacific Ocean.
The Robertsons watch their sailboat sink beneath the waves, and wait for the whales to strike again.
I remember the whale going round us at night.
The first night, the big whale swam round us, and he was huffing and puffing.
And we were scared to death.
Killer whales are known to circle their prey before an attack.
We thought, this is it.
The killer whales will now come back.
But instead, by morning, the whales disappear.
The question is, why did they attack "The Lucette" in the first place? Did they ram it in anger as the sperm whale in the Essex tragedy supposedly did? Or did they somehow mistake the boat for prey? The answer may lie in how killer whales hunt their victims.
Scientist Peter Tyack has been recording the subtle sounds of their sonar.
[Clicking.]
That click energy goes out of the whale, into the water, and reflects off everything around it.
The sonar of all toothed whales is highly focused.
It's like a flashlight beam of about six degrees.
So very narrow beam, and the animal scans around looking for prey until it gets one in the beam.
Killer whales have the keen sense of hearing characteristic of all mammals.
However, as a part of their adaptation to life underwater, it has evolved into a form of sonar called echolocation.
The animal processes those echoes.
And its brain tells it: That is a mullet, that is a seal.
And when they're hunting other whales that have the ability to hear their sonar, they modify it; creating what scientists call "stealth sonar.
" [Clicking.]
They make fainter clicks, they make fewer of them, and they don't make them as regular, so they're harder to hear.
With senses like this, it seems highly unlikely that a killer whale would mistake the sounds and shape of a sailboat for the sounds and shape of a whale.
The boat, which is an air-filled cavity in the water, would be a very good sonar target, but it would be really different from another living organism.
So I'm sure that a whale could discriminate a boat from, let's say, a Baleen Whale.
Historian Richard Ellis has come up with his own theory for the attack.
It might be the killer whale's idea of a big joke.
They catch seals, and then they flip 'em up in the air.
It's very difficult to figure out why they would do either sinking a boat and then swimming away, or playing with their prey when it's already dead.
Maybe it's fun to do that.
Whales do frequently play with objects, but I think the idea that killer whales would ram a ship in the sense of play just doesn't make sense to me.
The Robertsons agree.
The big whale's head was split open, and blood was in the water trailing behind it.
And I know that wild animals don't take chances.
They must have committed to the attack.
If it was a deliberate attack, the Robertsons insist they did not provoke it.
For victims and experts alike, the whales' motive remains a mystery.
However, the consequences are all too obvious.
For over a month, the Robertsons are at the mercy of the underwater universe; subsisting off rain water and the occasional fish.
I remember talking with Doughal one night and he said, "the school of survivors is harsh, because there are no failures.
" And that is very true.
Then, on the 38th day, they are spotted by a Japanese trawler and rescued.
They have survived the attack of one of the world's most powerful predators.
In the last five years, there have been five cases of killer whales attacking humans.
Almost exclusively by captive animals in aquariums.
And only one fatality.
It's a very different story with the next contender in the countdown to the underwater predator deadliest to man.
It's kind of like diving with a bunch of Velociraptors from Jurassic Park.
Though the killer whale is the most powerful hunter to roam the underwater universe, the next animal in the countdown to the underwater predator deadliest to man is one of the most aggressive.
Number four is the Humboldt Squid.
When I see the Humboldt Squid coming out of that curtain of darkness at me, I get the same feeling.
It's one of a tinge of fear, awe, and respect.
Humboldt Squid are like the Earth's resident alien species.
6 feet long, weighing over 100 pounds.
The Humboldt Squid's traditional hunting ground extends from the Chilean coast to Baja, California.
Mexican fisherman call it el diablo rojo-- the red devil.
We don't have a fossil record on these animals because they're soft, but we do have some evidence of giant squid in the past, and they're just as big and just as aggressive now as they were back in the prehistoric days.
Underwater researcher Scott Cassell is one of the few documenting the anatomy and hunting technique of this bizarre predator.
[Heart beating.]
They have three hearts and they pump blue blood through their veins.
They also have some of the largest gills of any squid species.
Scientists speculate that the combination of 3 hearts and large gills allows the Humboldt Squid to survive in low oxygen environments.
This means they can hunt throughout the deep, in places other predators can't go.
The squid will go from a 2,000 foot depth and come up, which is a thousand pounds of pressure difference per square inch and go through a 40 degree temperature change and not show any effect.
Once in a new hunting ground, they devour any prey they find.
They eat anything.
One Humboldt Squid will eat 21,000 pounds of fish in its lifetime.
Each.
Scott discovers early in his research that not only do they hunt prey indiscriminately; they attack with little provocation.
My worst attack with Humboldt Squid was my first.
1995.
Scott is diving on a routine research trip.
I rolled off into the water and I start looking at this squid.
And I was so happy.
This was like a life's work.
Finally I got to see a giant squid species.
At first, Scott is mesmerized by the animal.
They have eyes that are just as developed as human eyes.
So when they look at you, you feel very disarmed.
Because they're studying you.
But that is the only human thing about them.
Scott notices that the squid seems to be putting on a light show.
They change from red to white, with amazing patterns and speed.
Dark red is the first color to disappear in seawater.
So they just go into invisibility right in front of you.
Humboldt Squid rapidly change skin color through specialized cells.
Experts believe the strobing has a deadly purpose--it's how they communicate.
You see this strobing effect, you know that this one's distracting you while one in solid red is coming up to hit you from behind.
But at the time, Scott is unaware of what is happening around him.
And as I was filming it, I was so fascinated by the strobing effect, I focused all my energy on that one animal.
I was being surrounded by a whole bunch of his buddies.
In the corner of my eye, I saw a flicker.
[Grunting.]
I was hit in the face so hard, the camera slammed into my face and broke my nose.
Tentacles grab hold of his body.
The power of these arms is really shocking.
It's like being held by steel cable.
This is a soft, squishy squid.
But when they tighten up and they grab you, with all those 30,000 to 40,000 teeth inside their sucker discs, you can't pull free.
And they grabbed and dragged me down to over 50 feet, which caused me to rupture my right ear drum.
The squid release him as suddenly as they attack and swim away.
Scott makes his way back to the surface.
He has survived what could have easily been a fatal attack.
And since that time, I have cables so that they can't pull me down.
I have armor.
Even with a chain mail suit, they will bite through and they will break your wrist.
So that's why I wear these aluminum gauntlets now.
Scott's experience isn't unique.
Fisherman of the area have had their own encounters with el diablo rojo.
I have spoke to eyewitnesses that have seen Mexican fisherman being killed and eaten by the squid.
They were ravaged by the squid so badly their own families could not identify who was who.
Though there are only two alleged fatalities, there is no way of knowing how many attacks like this go unreported.
What we have is a mega predator that lives amongst us, and it's just a matter of time until more people get attacked.
Underwater predators like the killer whale and Humboldt Squid are capable of attacking humans, but they don't do it often.
The next contender is a notorious killer.
Number three in the countdown, the Great White Shark.
The largest predatory fish on Earth, reaching lengths of more than 20 feet and weighing up to 5,000 pounds.
The Great White Shark is found in coastal waters in all the major oceans.
Sharks have survived all the world's massive extinction events.
I mean, 65 million years ago, dinosaurs went extinct.
Sharks still hung around.
Of all the predators on the list, it's the one feared the most.
Peter Benchley wrote "Jaws" in 1974, and everybody in the world became scared of sharks.
People have always had an inherent fascination and also fear of sharks.
There are early records from even Aristotle talking about sharks perceived as being monsters in the ocean.
The Great White Shark's reputation is well deserved.
There is nothing a human can do to combat a 17 foot, 4,000 pound animal with teeth as sharp as steak knives that can swim at 35 to 40 miles an hour.
If the shark wants to eat you, it will.
It was a Great White that attacked the skin diver.
No one knows better than recreational diver Jack Rochette.
In 1964, Jack is 21 and an avid scuba diver.
On January 13th, he and his friends decide to charter a dive boat to a well-known spearfishing location.
I'd had close calls with the Great Whites before, and there'd been a couple of attacks, one the year before, and you know, I mean, the thing is, you were a fool if you went to the Farallons anymore.
And I'd already made a promise that I'd never go back.
But Jack is persuaded by his friends to make one last trip.
There was four of us that went together.
Three of them ran out of air, so they all went in.
I stayed down.
I was kind of chasing this big fish, you know.
Jack is now the only one left in the water--or so he thinks.
All of a sudden, boom.
I thought a mountain hit me.
A shark just grabbed me.
Fantastic force.
I mean, literally jumped out of the water with me in his mouth.
And he just shook me like a rag doll.
He had both legs in his jaws at one time.
There was blood in the water and all I could see is teeth.
Over the last decade, scientists like Dr.
Neil Hammerschlag have been trying to learn more about these elusive predators.
Though he studies all species of sharks, Great Whites hold a particular fascination.
Sharks have a great sense of smell.
For example, a Great White Shark, almost 20% of its brain is dedicated to smell alone.
A lot of these open ocean sharks are pretty much like the bloodhounds of the ocean.
Great Whites are a formidable foe.
Not just because of their sense of smell, but because of their extra senses.
Sharks have one of the most unique, highly developed senses.
In fact they have a couple that we don't even possess as humans.
Sense number six is the ability to detect movement.
Sharks are equipped with pressure sensors, a network of vessels that can detect vibrations in the water.
It also gives them an uncanny ability to detect approaching frontal pressure systems so they can avoid severe weather.
Sense number seven is called electroreception.
Sharks are equipped with a group of sensory organs in their heads that allows them to detect electric currents emanating from living organisms.
Sharks can detect five one billionths of a volt.
That would be like trying to establish an electrical current with a battery and electrodes 10,000 miles apart, and it working.
Sharks are five million times more sensitive to electrical impulses than any known creature in the animal kingdom.
All animals emit an electromagnetic field-- even humans.
I mean, there was blood in the water and I'm trying to get him off my legs, you know, I mean, that's all I could think about.
And then I quit fighting and when I quit fighting, he released me.
I came up to the surface.
I didn't know what happened.
I didn't know if I died and went to heaven.
I started looking around and there was a very big shark.
Holy crimy, this thing's huge! 27 miles off the San Francisco coast, a 21-year-old Jack Rochette is being attacked by a Great White Shark.
Number three in the countdown to the underwater predator deadliest to man.
It was thicker than I was tall.
25 feet, 3 or 4,000 pounds.
I mean, this is kind of almost unbelievable.
I mean, people just can't imagine.
All I want to do is get back to the boat, you know, I kept on trying to go towards the boat and every time I'd try to swim, my feet, you know, they weren't working right.
I wasn't going anywhere.
The shark is still circling him, baring its razor sharp teeth.
Their teeth have their own nerve supply and blood supply.
And they can actually almost splay them out like cats claws and you know, manipulate like fingertips on whatever it's touching.
Teeth perfectly designed to latch on to prey and kill.
I started getting really weak, and I'm going, oh, my God, I can't give up now.
I mean, the shark kept circling under me.
I was like four inches away from his eye and I thought, I'm gonna die.
And all of a sudden, man, that shark disappeared and I never saw him again.
Why did the Great White swim away and not finish off its victim? Experts have a theory.
I got it.
96% of the cases, the shark bites once and never is seen again.
If they thought you were their food, they would bite you pretty hard.
Sharks, in order to be successful, they make the first bite fatal.
The way sharks eat seals or fish is not the same way they bite people.
Great White Sharks attack because they're looking for food.
So what they really need in order to justify the energy expenditure of hauling a 2,000 pound body up through the water at 40 miles an hour, they need blubber.
They need a whale, they need a seal.
And when they bite a human, what is happening is an investigatory bite.
They do investigate things with their teeth.
Because we've seen sharks, we assume that sharks have seen us.
That's not necessarily true.
You might run into a 17 foot White Shark that has never seen a human.
Whether an exploratory bite or a deliberate attack, the injuries are devastating.
Jack is flown by Coast Guard helicopter to a hospital in San Francisco and rushed into surgery.
They said I lost like 7 pints of blood.
I was cut on both sides of the leg without cutting this artery.
There's an artery that runs on the inside of your leg, and they say if that's cut, you're not going to live.
It was a miracle that I survived.
Jack was lucky, but why he was singled out by the shark that attacked him, he will never know.
Why will a shark swim amongst a group of people today and do absolutely nothing and that same shark will swim through another group of people tomorrow and this time it bites somebody.
That's what we don't know.
We don't know the motivation.
The shark's vicious bite and unpredictability earns them the title of the deep's most feared killer.
But when it comes to human fatalities, they're not as deadly as we think.
Just to put it in perspective, last year there was only four fatal attacks reported globally.
Unfortunately for them they get a bad rap, because their fingertips happen to be their teeth.
But these statistics include all shark species.
The Great White is responsible for only three fatalities in the last five years.
It pales in comparison with the next predator in the countdown.
A vicious killer with an even more powerful bite.
This one seems to enjoy the taste of human flesh.
They're opportunistic feeders, and they don't discriminate whether you're a wallaby, a kangaroo, a pig, or indeed a human being.
They're just after something to eat.
Predator number two in the countdown is the saltwater Crocodile.
The largest living reptile on Earth, it can grow to more than 23 feet long, and weigh up to 2 tons.
Its range extends from India to Australia, where it has earned a reputation as a ruthless man-eater.
An 8-year-old girl has been snatched by a Crocodile Diana Kerr was sleeping in a tent with her young baby and husband When a saltwater croc dragged her away There was the screaming.
Saltwater Crocodiles have a reputation of being particularly fierce and particularly dangerous.
I've spent time in the United States and alligators are little puppy dogs compared to the saltwater Crocodile.
It almost grabbed the baby.
Park rangers to the scene There's no way you would go to the water's edge in northern Australia without being very careful about where you are.
Police don't hold much hope the little girl survived.
Saltwater Crocodiles possess acute hearing and vision as well as a bizarre set of receptors on their skin that enable them to sense subtle vibrations underwater.
When potential prey enters the water, the croc's pressure receptors pick up the vibrations.
Alerted to a potential meal, the croc begins a methodical study of its intended victim.
Crocodiles appear to follow routines.
They cue in to behaviors over days, if not weeks.
When the Crocodile is confident of its victims' routine, it is ready to make a move.
They glide through the water.
They don't cause a ripple.
Its victim doesn't stand a chance.
Number two on the countdown to the underwater predator deadliest to man Is the saltwater Crocodile.
After carefully studying its victim's routine, the giant reptile is ready to attack.
And as soon as the animal comes down to drink at the water's edge, it's ready there to launch itself out of the water using its tail as its main propulsive force.
If you look at the tail of a Crocodile, it's thick muscle.
And it generates huge momentum, huge force, and it can launch itself out of the water, grab the prey, and bring it back into the water.
There it will death roll it, take it under water, and most likely drown it.
Saltwater Crocodiles latch on to prey with a bone crunching bite ten times more powerful than a lion's.
Scientists have measured bite forces of round about 10,000 Newtons.
Now that's like putting a rock on top of you that weighs a ton.
I've been bitten by small Crocodiles about this size here.
One took me through the hand, and one of my students had to use a screwdriver to actually pry it off my hand.
The Australian Crocodile hunter, the late Steve Irwin, spent his last few years working with Craig Franklin along with a team of researchers from the Australia Zoo and the university of Queensland, to track saltwater Crocodiles.
They capture them in the wild, tag them, and track their migration patterns with satellite telemetry.
Preliminary results have been astounding--saltwater Crocodiles are efficient ocean swimmers.
We've tracked them swimming over 900 kilometers.
Crocodiles have figured out how to hop a ride on surface currents and roam the coasts of northern Australia, southeast Asia and India.
Silent, smart and patient, the saltwater Crocodile is one of the underwater universe's most successful stealth killers.
If I was down there, I would never turn my back on a Crocodile.
Ever.
Since much of the giant reptile's range is in remote areas, experts believe that many human fatalities go unreported.
The data that does exist estimates some 150 attacks and 50 deaths over the past five years.
But the massive saltwater Crocodile is not the ultimate predator on the countdown.
That distinction falls to a very different kind of killer-- one that is almost invisible.
Number one in the countdown to the underwater universe's deadliest predator, is the Box Jellyfish.
Up to 10 feet long and weighing in at only 4 pounds, they get their name from the cube-like shape of their bell.
The biggest and most lethal species of Box Jellyfish is found in the coastal waters of Australia and the Indo-Pacific.
It may look insignificant, but what it lacks in strength, it makes up for with the deadliest venom on earth.
They can kill a full-grown human being in less than three minutes.
Now there's no other snakes, spiders, scorpions, anything else on this planet that can do that.
Venom potencies are measured on a scale using a unit called LD50.
According to this scale, the venom of the Box Jellyfish is eight times more potent than a scorpion's.
50 times more potent than a rattlesnake, and 150 times more potent than the common bee sting.
Along the beaches of Australia, signs warn swimmers that they swim at their own risk.
But this predator isn't confined to the coastline.
People have always sort of assumed that like most jellyfish, Box Jellyfish float aimlessly in the water, at the mercy of currents.
But Box Jellyfish are distinctly different because they're active swimmers.
And they have image-forming eyes.
24 eyes give Box Jellyfish an extraordinary view of their prey.
They can actually put themselves where they want to in the water system.
Now for an animal that doesn't have a higher processing unit like a brain, this is really quite mind-blowing as to how they're managing to do this.
Queensland, Australia.
Calliope River.
The temperature hovers around 100 degree fahrenheit.
Factory employee Jeff Shardlow and his wife Ruth sit in the shade while their children, Rachel, age 10, and Sam, age 12, play at the river's edge.
Rachel tends to squeal a lot when she's excited.
So she's squealing with delight and splashing and you know, having a great time.
And I do remember Jeff actually said, "I wish Rachel wouldn't squeal so much, because you never quite know if she's in trouble or if she's having fun.
" [Girl screaming.]
As if on cue, Rachel's squeals of joy turn to screams of agony.
Something has grabbed hold of her legs.
Queensland, Australia.
The underwater predator deadliest to man has struck again.
Number one on the countdown, a venomous Box Jellyfish, has grabbed hold of 10-year-old Rachel Shardlow's legs and won't let go.
The best analogy I've heard for it is if you take say a large kitchen knife and you heat it up over a flame so it's red hot, and you drag the back of it across your skin.
Times that by about a factor of ten and hold onto it.
So the pain doesn't come and go, it stays at that level.
Then I saw her leg.
Something I've never, ever seen before.
And I hope I never do again.
It's a mass of tentacles; completely wrapped around one of her legs.
It takes one nine foot tentacle to cause a fatal injury, and Box Jellyfish can have up to 60.
So if you do the math, potentially a really large box jellyfish has enough stinging power to kill maybe sixty grown adults.
I immediately tried to pull those tentacles off with my fingers.
They just don't budge.
They're just stuck fast.
They have minute little stinging cells known as nematocysts.
And these stinging cells are probably only around 50 microns long; So a fraction of a millimeter.
But they can have as many as a million in say a square centimeter.
The pressure that these stinging cells is under is around 20,000 pounds per square inch or psi.
That's around the same pressure as what a 45-caliber bullet will fire at.
At that kind of same pressure.
They can actually go from being un-discharged to fully discharged in one 25 thousandths of a second.
It's one of the fastest cellular processes of any of the animals on earth.
Meanwhile, the commotion on the river bank has attracted the attention of a couple camping nearby.
And he said it's a Box Jellyfish.
And his wife has then run back and grabbed a bottle of vinegar.
They quickly splash Rachel's body with vinegar.
And it's amazing that as soon as the vinegar's on, they just let go.
The vinegar inhibits any more stinging cells from injecting venom, but it does nothing to stop the venom already coursing through Rachel's body.
By now she barely has a pulse.
The venom is really specific to targeting vertebrate hearts.
It shuts down the heart muscle.
[Siren.]
On the way to the hospital, Rachel is given an anti-venom and regains consciousness.
Minutes later the pain is so intense, doctors worry she will suffer a heart attack.
And then it was decided that they would put her in an induced coma and lower her body heat to stop brain damage.
Now, it's a waiting game.
Was the anti-venom administered in time? The doctors weren't reassuring at all.
They said that we can't give you any false hopes.
If I had met her at the hospital and seen the extent of her injuries, I would not have held out a lot of hope for her survival.
Two days later, Rachel comes out of the coma.
Somehow, she survives the worst Box Jellyfish sting in recorded history.
There were the baddest ones.
I also got stung here on my arm.
She survived more of these stings than anybody else has ever had on record.
And she's alive.
Where full grown men die from half the stings.
Though her physical scars are fading, her psychological scars will take longer to heal.
When asked if she would go back in the river, she is adamant.
No, never again.
Maybe like just putting my feet in but no higher than like my knees.
There are no accurate figures for Box Jellyfish fatalities because many attacks happen in remote areas.
However, existing data places this predator well above Killer Whales, Humboldt Squid, Great White Sharks and even above the saltwater Crocodile.
With up to 200 attacks and over 100 human fatalities in the last 5 years, the Box Jellyfish is number one on the countdown to the underwater predator deadliest to man.
But the planet we live on is in flux.
The countdown applies to the oceans we know today, but what about in years to come? Many experts believe the balance of power is shifting.
If we look at the modern ocean, the numbers of top predators like whales, sharks, are drastically reduced because of overfishing.
Get that punt going! Got it! [Indistinct chatter.]
Scientists are capturing and tagging sharks to track their migration and impact on the ocean's ecosystems.
What we've seen is as we remove these apex predators, they tend to change the abundance and behavior of the populations below them on the food chain.
So what happens is the next level down increases, and then it feeds on the next level down.
The whole balance turns topsy-turvy, and we don't know how this works out.
But we're gonna find out in a big, rapid hurry.
According to squid expert Scott Cassell, number four in the countdown, the Humboldt Squid, is taking advantage of this disruption in the food chain.
The Humboldt Squid population has exploded in historic proportions because its predators have been primarily wiped out.
There are hundreds of millions of these animals off the West Coast of the United States and they were never there 50 years ago.
Humboldt Squid now reach as far as Russia.
Across the Pacific, we have even found them in the Philippines.
I honestly believe it's only a matter of time until they enter into the Atlantic and the Caribbean.
And we're going to find Humboldt Squid and nothing else pretty soon.
It won't be long before there is a new top predator roaming the dark recesses of the planet's oceans, ready and willing to strike.
Hunters of the deep.
And he just shook me like a rag doll.
There is nothing a human can do to combat a 4,000 pound animal.
Since the dawn of life, they've ruled their universe.
If you were around for tens of millions of years, you would be good at what you did, too.
But the balance of power is shifting.
Classic killers are being pushed down the deep's most deadly list as others move up.
You don't really know how far away they are until they hit you.
Which will be the new number one, and why? Countdown to the deadliest predator in the underwater universe.
Underwater Universe 1x02 Predators of the Deep 3.
5 billion years ago, Earth's earliest life forms are born in the underwater universe single-celled organisms that evolve to produce energy through photosynthesis.
In return, they produce oxygen, sparking the evolution of life on Earth.
Over hundreds of millions of years, the deep becomes the breeding ground for the deadliest predators on Earth.
Predators in the ocean are historic and epic compared to what we have on land.
If you look at amazing creatures that live today, the ocean takes the cake.
Today's oceans are filled with predators that can kill a human being in a matter of seconds.
Five top the list.
Five animals that no thinking human should tangle with.
Which one is responsible for the greatest number of human fatalities in the last five years? Human beings have always been afraid of big scary things in the ocean.
Big scary things evolve in the ocean because a predator takes hold of a particular niche and is able to exploit it so well that it can grow huge.
And of course it exploits it by developing teeth.
Many of the top predators of the past use the power of their size and a bone-crunching bite to kill their prey.
The same is true today.
[Gasps.]
It's coming right toward us, Michael.
As far as an animal that I wouldn't want to swim with, Orca Whales are terrifying.
Number five in the countdown to the underwater predator deadliest to man is the Orca.
Also known as the killer whale.
12,000 pounds.
30 feet long.
These marine mammals are apex predators.
Hunted by no other animal.
They belong to a suborder of whales called "toothed whales.
" Fierce hunters, equipped with massive jaws and teeth that curve inward.
They can latch onto any prey.
From fish, to seals, to whales almost twice their size.
Killer whales are the most widely distributed large mammals in the world.
They live anywhere they want to.
They live in the arctic, the antarctic, the tropics; they live everywhere.
In Antarctica, they've devised a cunning way to rock seals off ice sheets.
To do it, they work in groups.
They have a complex family structure.
They communicate with one another when they're hunting, when they're diving.
Occasionally, whales have used their intelligence and sophisticated hunting techniques to take on humans.
[Indistinct chatter.]
In the coastal town of Falmouth, England, in the local maritime museum, three brothers examine the tiny dinghy that saved their lives.
Do you remember how that got rigged? It's a stark reminder of a brutal confrontation with a pod of killer whales.
In 1968, their father, Navy veteran Doughal Robertson, is a struggling farmer in rural England.
Douglas, the eldest son, is 14.
Twin brothers Sandy and Neil are nine.
We had no idea what sailing in a boat at sea was like.
And Doughal used to talk about it second nature.
And one day Neil said, "well, daddy's a sailor; Why don't we sail 'round the world?" And mother said, isn't that a marvelous idea? Well, no, she said, "that's a wonderful idea.
" A wonderful idea.
Whatever.
And that was it.
The seed of an idea is sown.
In 1970, their father sells the family farm and buys a sturdy 43 foot wooden sailboat called "the Lucette.
" A year and a half later, the Robertsons are 200 miles southwest of the Galapagos Islands, in the same area where back in 1820, a close relative of killer whales, a sperm whale, turns and charges a whaling ship called "The Essex".
An eyewitness calls it an act of revenge on the men who attacked the whales first.
The 238 ton ship is smashed in two and sinks, inspiring the great American novel "Moby Dick".
A century later in the very same waters, the Robertson family starts another day onboard "The Lucette".
12-year-old Sandy has the morning watch.
Off on the starboard bow, quite a long way, we saw whales.
And we didn't take any notice of it because we'd gotten quite used to them.
But these whales are anything but friendly.
The first indication I had was an almighty crash.
Bang.
Bang bang.
That's how the strikes came.
And they were so severe that they lifted, bloody lifted "The Lucette" out of the water by maybe a foot.
One 12,000 pound whale, traveling at 15 miles per hour has the impact of a wrecking ball.
My cup of tea left the boat up in the air like that and then came back down again.
And as I looked over the side, there was this huge killer whale.
I knew that was an attack, because the damage, it was just a big hole in the boat.
Dad was up to his knees in water.
And then he said, "abandon ship.
" And I said to him, "abandon ship to where?" We're in the middle of the Pacific Ocean.
The Robertsons watch their sailboat sink beneath the waves, and wait for the whales to strike again.
I remember the whale going round us at night.
The first night, the big whale swam round us, and he was huffing and puffing.
And we were scared to death.
Killer whales are known to circle their prey before an attack.
We thought, this is it.
The killer whales will now come back.
But instead, by morning, the whales disappear.
The question is, why did they attack "The Lucette" in the first place? Did they ram it in anger as the sperm whale in the Essex tragedy supposedly did? Or did they somehow mistake the boat for prey? The answer may lie in how killer whales hunt their victims.
Scientist Peter Tyack has been recording the subtle sounds of their sonar.
[Clicking.]
That click energy goes out of the whale, into the water, and reflects off everything around it.
The sonar of all toothed whales is highly focused.
It's like a flashlight beam of about six degrees.
So very narrow beam, and the animal scans around looking for prey until it gets one in the beam.
Killer whales have the keen sense of hearing characteristic of all mammals.
However, as a part of their adaptation to life underwater, it has evolved into a form of sonar called echolocation.
The animal processes those echoes.
And its brain tells it: That is a mullet, that is a seal.
And when they're hunting other whales that have the ability to hear their sonar, they modify it; creating what scientists call "stealth sonar.
" [Clicking.]
They make fainter clicks, they make fewer of them, and they don't make them as regular, so they're harder to hear.
With senses like this, it seems highly unlikely that a killer whale would mistake the sounds and shape of a sailboat for the sounds and shape of a whale.
The boat, which is an air-filled cavity in the water, would be a very good sonar target, but it would be really different from another living organism.
So I'm sure that a whale could discriminate a boat from, let's say, a Baleen Whale.
Historian Richard Ellis has come up with his own theory for the attack.
It might be the killer whale's idea of a big joke.
They catch seals, and then they flip 'em up in the air.
It's very difficult to figure out why they would do either sinking a boat and then swimming away, or playing with their prey when it's already dead.
Maybe it's fun to do that.
Whales do frequently play with objects, but I think the idea that killer whales would ram a ship in the sense of play just doesn't make sense to me.
The Robertsons agree.
The big whale's head was split open, and blood was in the water trailing behind it.
And I know that wild animals don't take chances.
They must have committed to the attack.
If it was a deliberate attack, the Robertsons insist they did not provoke it.
For victims and experts alike, the whales' motive remains a mystery.
However, the consequences are all too obvious.
For over a month, the Robertsons are at the mercy of the underwater universe; subsisting off rain water and the occasional fish.
I remember talking with Doughal one night and he said, "the school of survivors is harsh, because there are no failures.
" And that is very true.
Then, on the 38th day, they are spotted by a Japanese trawler and rescued.
They have survived the attack of one of the world's most powerful predators.
In the last five years, there have been five cases of killer whales attacking humans.
Almost exclusively by captive animals in aquariums.
And only one fatality.
It's a very different story with the next contender in the countdown to the underwater predator deadliest to man.
It's kind of like diving with a bunch of Velociraptors from Jurassic Park.
Though the killer whale is the most powerful hunter to roam the underwater universe, the next animal in the countdown to the underwater predator deadliest to man is one of the most aggressive.
Number four is the Humboldt Squid.
When I see the Humboldt Squid coming out of that curtain of darkness at me, I get the same feeling.
It's one of a tinge of fear, awe, and respect.
Humboldt Squid are like the Earth's resident alien species.
6 feet long, weighing over 100 pounds.
The Humboldt Squid's traditional hunting ground extends from the Chilean coast to Baja, California.
Mexican fisherman call it el diablo rojo-- the red devil.
We don't have a fossil record on these animals because they're soft, but we do have some evidence of giant squid in the past, and they're just as big and just as aggressive now as they were back in the prehistoric days.
Underwater researcher Scott Cassell is one of the few documenting the anatomy and hunting technique of this bizarre predator.
[Heart beating.]
They have three hearts and they pump blue blood through their veins.
They also have some of the largest gills of any squid species.
Scientists speculate that the combination of 3 hearts and large gills allows the Humboldt Squid to survive in low oxygen environments.
This means they can hunt throughout the deep, in places other predators can't go.
The squid will go from a 2,000 foot depth and come up, which is a thousand pounds of pressure difference per square inch and go through a 40 degree temperature change and not show any effect.
Once in a new hunting ground, they devour any prey they find.
They eat anything.
One Humboldt Squid will eat 21,000 pounds of fish in its lifetime.
Each.
Scott discovers early in his research that not only do they hunt prey indiscriminately; they attack with little provocation.
My worst attack with Humboldt Squid was my first.
1995.
Scott is diving on a routine research trip.
I rolled off into the water and I start looking at this squid.
And I was so happy.
This was like a life's work.
Finally I got to see a giant squid species.
At first, Scott is mesmerized by the animal.
They have eyes that are just as developed as human eyes.
So when they look at you, you feel very disarmed.
Because they're studying you.
But that is the only human thing about them.
Scott notices that the squid seems to be putting on a light show.
They change from red to white, with amazing patterns and speed.
Dark red is the first color to disappear in seawater.
So they just go into invisibility right in front of you.
Humboldt Squid rapidly change skin color through specialized cells.
Experts believe the strobing has a deadly purpose--it's how they communicate.
You see this strobing effect, you know that this one's distracting you while one in solid red is coming up to hit you from behind.
But at the time, Scott is unaware of what is happening around him.
And as I was filming it, I was so fascinated by the strobing effect, I focused all my energy on that one animal.
I was being surrounded by a whole bunch of his buddies.
In the corner of my eye, I saw a flicker.
[Grunting.]
I was hit in the face so hard, the camera slammed into my face and broke my nose.
Tentacles grab hold of his body.
The power of these arms is really shocking.
It's like being held by steel cable.
This is a soft, squishy squid.
But when they tighten up and they grab you, with all those 30,000 to 40,000 teeth inside their sucker discs, you can't pull free.
And they grabbed and dragged me down to over 50 feet, which caused me to rupture my right ear drum.
The squid release him as suddenly as they attack and swim away.
Scott makes his way back to the surface.
He has survived what could have easily been a fatal attack.
And since that time, I have cables so that they can't pull me down.
I have armor.
Even with a chain mail suit, they will bite through and they will break your wrist.
So that's why I wear these aluminum gauntlets now.
Scott's experience isn't unique.
Fisherman of the area have had their own encounters with el diablo rojo.
I have spoke to eyewitnesses that have seen Mexican fisherman being killed and eaten by the squid.
They were ravaged by the squid so badly their own families could not identify who was who.
Though there are only two alleged fatalities, there is no way of knowing how many attacks like this go unreported.
What we have is a mega predator that lives amongst us, and it's just a matter of time until more people get attacked.
Underwater predators like the killer whale and Humboldt Squid are capable of attacking humans, but they don't do it often.
The next contender is a notorious killer.
Number three in the countdown, the Great White Shark.
The largest predatory fish on Earth, reaching lengths of more than 20 feet and weighing up to 5,000 pounds.
The Great White Shark is found in coastal waters in all the major oceans.
Sharks have survived all the world's massive extinction events.
I mean, 65 million years ago, dinosaurs went extinct.
Sharks still hung around.
Of all the predators on the list, it's the one feared the most.
Peter Benchley wrote "Jaws" in 1974, and everybody in the world became scared of sharks.
People have always had an inherent fascination and also fear of sharks.
There are early records from even Aristotle talking about sharks perceived as being monsters in the ocean.
The Great White Shark's reputation is well deserved.
There is nothing a human can do to combat a 17 foot, 4,000 pound animal with teeth as sharp as steak knives that can swim at 35 to 40 miles an hour.
If the shark wants to eat you, it will.
It was a Great White that attacked the skin diver.
No one knows better than recreational diver Jack Rochette.
In 1964, Jack is 21 and an avid scuba diver.
On January 13th, he and his friends decide to charter a dive boat to a well-known spearfishing location.
I'd had close calls with the Great Whites before, and there'd been a couple of attacks, one the year before, and you know, I mean, the thing is, you were a fool if you went to the Farallons anymore.
And I'd already made a promise that I'd never go back.
But Jack is persuaded by his friends to make one last trip.
There was four of us that went together.
Three of them ran out of air, so they all went in.
I stayed down.
I was kind of chasing this big fish, you know.
Jack is now the only one left in the water--or so he thinks.
All of a sudden, boom.
I thought a mountain hit me.
A shark just grabbed me.
Fantastic force.
I mean, literally jumped out of the water with me in his mouth.
And he just shook me like a rag doll.
He had both legs in his jaws at one time.
There was blood in the water and all I could see is teeth.
Over the last decade, scientists like Dr.
Neil Hammerschlag have been trying to learn more about these elusive predators.
Though he studies all species of sharks, Great Whites hold a particular fascination.
Sharks have a great sense of smell.
For example, a Great White Shark, almost 20% of its brain is dedicated to smell alone.
A lot of these open ocean sharks are pretty much like the bloodhounds of the ocean.
Great Whites are a formidable foe.
Not just because of their sense of smell, but because of their extra senses.
Sharks have one of the most unique, highly developed senses.
In fact they have a couple that we don't even possess as humans.
Sense number six is the ability to detect movement.
Sharks are equipped with pressure sensors, a network of vessels that can detect vibrations in the water.
It also gives them an uncanny ability to detect approaching frontal pressure systems so they can avoid severe weather.
Sense number seven is called electroreception.
Sharks are equipped with a group of sensory organs in their heads that allows them to detect electric currents emanating from living organisms.
Sharks can detect five one billionths of a volt.
That would be like trying to establish an electrical current with a battery and electrodes 10,000 miles apart, and it working.
Sharks are five million times more sensitive to electrical impulses than any known creature in the animal kingdom.
All animals emit an electromagnetic field-- even humans.
I mean, there was blood in the water and I'm trying to get him off my legs, you know, I mean, that's all I could think about.
And then I quit fighting and when I quit fighting, he released me.
I came up to the surface.
I didn't know what happened.
I didn't know if I died and went to heaven.
I started looking around and there was a very big shark.
Holy crimy, this thing's huge! 27 miles off the San Francisco coast, a 21-year-old Jack Rochette is being attacked by a Great White Shark.
Number three in the countdown to the underwater predator deadliest to man.
It was thicker than I was tall.
25 feet, 3 or 4,000 pounds.
I mean, this is kind of almost unbelievable.
I mean, people just can't imagine.
All I want to do is get back to the boat, you know, I kept on trying to go towards the boat and every time I'd try to swim, my feet, you know, they weren't working right.
I wasn't going anywhere.
The shark is still circling him, baring its razor sharp teeth.
Their teeth have their own nerve supply and blood supply.
And they can actually almost splay them out like cats claws and you know, manipulate like fingertips on whatever it's touching.
Teeth perfectly designed to latch on to prey and kill.
I started getting really weak, and I'm going, oh, my God, I can't give up now.
I mean, the shark kept circling under me.
I was like four inches away from his eye and I thought, I'm gonna die.
And all of a sudden, man, that shark disappeared and I never saw him again.
Why did the Great White swim away and not finish off its victim? Experts have a theory.
I got it.
96% of the cases, the shark bites once and never is seen again.
If they thought you were their food, they would bite you pretty hard.
Sharks, in order to be successful, they make the first bite fatal.
The way sharks eat seals or fish is not the same way they bite people.
Great White Sharks attack because they're looking for food.
So what they really need in order to justify the energy expenditure of hauling a 2,000 pound body up through the water at 40 miles an hour, they need blubber.
They need a whale, they need a seal.
And when they bite a human, what is happening is an investigatory bite.
They do investigate things with their teeth.
Because we've seen sharks, we assume that sharks have seen us.
That's not necessarily true.
You might run into a 17 foot White Shark that has never seen a human.
Whether an exploratory bite or a deliberate attack, the injuries are devastating.
Jack is flown by Coast Guard helicopter to a hospital in San Francisco and rushed into surgery.
They said I lost like 7 pints of blood.
I was cut on both sides of the leg without cutting this artery.
There's an artery that runs on the inside of your leg, and they say if that's cut, you're not going to live.
It was a miracle that I survived.
Jack was lucky, but why he was singled out by the shark that attacked him, he will never know.
Why will a shark swim amongst a group of people today and do absolutely nothing and that same shark will swim through another group of people tomorrow and this time it bites somebody.
That's what we don't know.
We don't know the motivation.
The shark's vicious bite and unpredictability earns them the title of the deep's most feared killer.
But when it comes to human fatalities, they're not as deadly as we think.
Just to put it in perspective, last year there was only four fatal attacks reported globally.
Unfortunately for them they get a bad rap, because their fingertips happen to be their teeth.
But these statistics include all shark species.
The Great White is responsible for only three fatalities in the last five years.
It pales in comparison with the next predator in the countdown.
A vicious killer with an even more powerful bite.
This one seems to enjoy the taste of human flesh.
They're opportunistic feeders, and they don't discriminate whether you're a wallaby, a kangaroo, a pig, or indeed a human being.
They're just after something to eat.
Predator number two in the countdown is the saltwater Crocodile.
The largest living reptile on Earth, it can grow to more than 23 feet long, and weigh up to 2 tons.
Its range extends from India to Australia, where it has earned a reputation as a ruthless man-eater.
An 8-year-old girl has been snatched by a Crocodile Diana Kerr was sleeping in a tent with her young baby and husband When a saltwater croc dragged her away There was the screaming.
Saltwater Crocodiles have a reputation of being particularly fierce and particularly dangerous.
I've spent time in the United States and alligators are little puppy dogs compared to the saltwater Crocodile.
It almost grabbed the baby.
Park rangers to the scene There's no way you would go to the water's edge in northern Australia without being very careful about where you are.
Police don't hold much hope the little girl survived.
Saltwater Crocodiles possess acute hearing and vision as well as a bizarre set of receptors on their skin that enable them to sense subtle vibrations underwater.
When potential prey enters the water, the croc's pressure receptors pick up the vibrations.
Alerted to a potential meal, the croc begins a methodical study of its intended victim.
Crocodiles appear to follow routines.
They cue in to behaviors over days, if not weeks.
When the Crocodile is confident of its victims' routine, it is ready to make a move.
They glide through the water.
They don't cause a ripple.
Its victim doesn't stand a chance.
Number two on the countdown to the underwater predator deadliest to man Is the saltwater Crocodile.
After carefully studying its victim's routine, the giant reptile is ready to attack.
And as soon as the animal comes down to drink at the water's edge, it's ready there to launch itself out of the water using its tail as its main propulsive force.
If you look at the tail of a Crocodile, it's thick muscle.
And it generates huge momentum, huge force, and it can launch itself out of the water, grab the prey, and bring it back into the water.
There it will death roll it, take it under water, and most likely drown it.
Saltwater Crocodiles latch on to prey with a bone crunching bite ten times more powerful than a lion's.
Scientists have measured bite forces of round about 10,000 Newtons.
Now that's like putting a rock on top of you that weighs a ton.
I've been bitten by small Crocodiles about this size here.
One took me through the hand, and one of my students had to use a screwdriver to actually pry it off my hand.
The Australian Crocodile hunter, the late Steve Irwin, spent his last few years working with Craig Franklin along with a team of researchers from the Australia Zoo and the university of Queensland, to track saltwater Crocodiles.
They capture them in the wild, tag them, and track their migration patterns with satellite telemetry.
Preliminary results have been astounding--saltwater Crocodiles are efficient ocean swimmers.
We've tracked them swimming over 900 kilometers.
Crocodiles have figured out how to hop a ride on surface currents and roam the coasts of northern Australia, southeast Asia and India.
Silent, smart and patient, the saltwater Crocodile is one of the underwater universe's most successful stealth killers.
If I was down there, I would never turn my back on a Crocodile.
Ever.
Since much of the giant reptile's range is in remote areas, experts believe that many human fatalities go unreported.
The data that does exist estimates some 150 attacks and 50 deaths over the past five years.
But the massive saltwater Crocodile is not the ultimate predator on the countdown.
That distinction falls to a very different kind of killer-- one that is almost invisible.
Number one in the countdown to the underwater universe's deadliest predator, is the Box Jellyfish.
Up to 10 feet long and weighing in at only 4 pounds, they get their name from the cube-like shape of their bell.
The biggest and most lethal species of Box Jellyfish is found in the coastal waters of Australia and the Indo-Pacific.
It may look insignificant, but what it lacks in strength, it makes up for with the deadliest venom on earth.
They can kill a full-grown human being in less than three minutes.
Now there's no other snakes, spiders, scorpions, anything else on this planet that can do that.
Venom potencies are measured on a scale using a unit called LD50.
According to this scale, the venom of the Box Jellyfish is eight times more potent than a scorpion's.
50 times more potent than a rattlesnake, and 150 times more potent than the common bee sting.
Along the beaches of Australia, signs warn swimmers that they swim at their own risk.
But this predator isn't confined to the coastline.
People have always sort of assumed that like most jellyfish, Box Jellyfish float aimlessly in the water, at the mercy of currents.
But Box Jellyfish are distinctly different because they're active swimmers.
And they have image-forming eyes.
24 eyes give Box Jellyfish an extraordinary view of their prey.
They can actually put themselves where they want to in the water system.
Now for an animal that doesn't have a higher processing unit like a brain, this is really quite mind-blowing as to how they're managing to do this.
Queensland, Australia.
Calliope River.
The temperature hovers around 100 degree fahrenheit.
Factory employee Jeff Shardlow and his wife Ruth sit in the shade while their children, Rachel, age 10, and Sam, age 12, play at the river's edge.
Rachel tends to squeal a lot when she's excited.
So she's squealing with delight and splashing and you know, having a great time.
And I do remember Jeff actually said, "I wish Rachel wouldn't squeal so much, because you never quite know if she's in trouble or if she's having fun.
" [Girl screaming.]
As if on cue, Rachel's squeals of joy turn to screams of agony.
Something has grabbed hold of her legs.
Queensland, Australia.
The underwater predator deadliest to man has struck again.
Number one on the countdown, a venomous Box Jellyfish, has grabbed hold of 10-year-old Rachel Shardlow's legs and won't let go.
The best analogy I've heard for it is if you take say a large kitchen knife and you heat it up over a flame so it's red hot, and you drag the back of it across your skin.
Times that by about a factor of ten and hold onto it.
So the pain doesn't come and go, it stays at that level.
Then I saw her leg.
Something I've never, ever seen before.
And I hope I never do again.
It's a mass of tentacles; completely wrapped around one of her legs.
It takes one nine foot tentacle to cause a fatal injury, and Box Jellyfish can have up to 60.
So if you do the math, potentially a really large box jellyfish has enough stinging power to kill maybe sixty grown adults.
I immediately tried to pull those tentacles off with my fingers.
They just don't budge.
They're just stuck fast.
They have minute little stinging cells known as nematocysts.
And these stinging cells are probably only around 50 microns long; So a fraction of a millimeter.
But they can have as many as a million in say a square centimeter.
The pressure that these stinging cells is under is around 20,000 pounds per square inch or psi.
That's around the same pressure as what a 45-caliber bullet will fire at.
At that kind of same pressure.
They can actually go from being un-discharged to fully discharged in one 25 thousandths of a second.
It's one of the fastest cellular processes of any of the animals on earth.
Meanwhile, the commotion on the river bank has attracted the attention of a couple camping nearby.
And he said it's a Box Jellyfish.
And his wife has then run back and grabbed a bottle of vinegar.
They quickly splash Rachel's body with vinegar.
And it's amazing that as soon as the vinegar's on, they just let go.
The vinegar inhibits any more stinging cells from injecting venom, but it does nothing to stop the venom already coursing through Rachel's body.
By now she barely has a pulse.
The venom is really specific to targeting vertebrate hearts.
It shuts down the heart muscle.
[Siren.]
On the way to the hospital, Rachel is given an anti-venom and regains consciousness.
Minutes later the pain is so intense, doctors worry she will suffer a heart attack.
And then it was decided that they would put her in an induced coma and lower her body heat to stop brain damage.
Now, it's a waiting game.
Was the anti-venom administered in time? The doctors weren't reassuring at all.
They said that we can't give you any false hopes.
If I had met her at the hospital and seen the extent of her injuries, I would not have held out a lot of hope for her survival.
Two days later, Rachel comes out of the coma.
Somehow, she survives the worst Box Jellyfish sting in recorded history.
There were the baddest ones.
I also got stung here on my arm.
She survived more of these stings than anybody else has ever had on record.
And she's alive.
Where full grown men die from half the stings.
Though her physical scars are fading, her psychological scars will take longer to heal.
When asked if she would go back in the river, she is adamant.
No, never again.
Maybe like just putting my feet in but no higher than like my knees.
There are no accurate figures for Box Jellyfish fatalities because many attacks happen in remote areas.
However, existing data places this predator well above Killer Whales, Humboldt Squid, Great White Sharks and even above the saltwater Crocodile.
With up to 200 attacks and over 100 human fatalities in the last 5 years, the Box Jellyfish is number one on the countdown to the underwater predator deadliest to man.
But the planet we live on is in flux.
The countdown applies to the oceans we know today, but what about in years to come? Many experts believe the balance of power is shifting.
If we look at the modern ocean, the numbers of top predators like whales, sharks, are drastically reduced because of overfishing.
Get that punt going! Got it! [Indistinct chatter.]
Scientists are capturing and tagging sharks to track their migration and impact on the ocean's ecosystems.
What we've seen is as we remove these apex predators, they tend to change the abundance and behavior of the populations below them on the food chain.
So what happens is the next level down increases, and then it feeds on the next level down.
The whole balance turns topsy-turvy, and we don't know how this works out.
But we're gonna find out in a big, rapid hurry.
According to squid expert Scott Cassell, number four in the countdown, the Humboldt Squid, is taking advantage of this disruption in the food chain.
The Humboldt Squid population has exploded in historic proportions because its predators have been primarily wiped out.
There are hundreds of millions of these animals off the West Coast of the United States and they were never there 50 years ago.
Humboldt Squid now reach as far as Russia.
Across the Pacific, we have even found them in the Philippines.
I honestly believe it's only a matter of time until they enter into the Atlantic and the Caribbean.
And we're going to find Humboldt Squid and nothing else pretty soon.
It won't be long before there is a new top predator roaming the dark recesses of the planet's oceans, ready and willing to strike.