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You can run, but you can╒t hide from the swarm.
We╒re counting down the top 10 most extreme swarms in the animal kingdom
and comparing them to a human caste of thousands.
Discover that size really does matter, when swarming is taken to The Most
Extreme.
Earth is the planet of extremes, extreme places╔ and extreme animals.
But some animals are more extreme than others.
Join us as we count down to find the most unusual and the most
extraordinary on The Most Extreme.
Our first contender in the countdown of extreme swarms can be found a
little close to home.
Just one mouse in the house can cause all kinds
of trouble.
In the wild, mice can also cause trouble that╒s because it doesn╒t take
long for one mouse to become a swarm.
The mouse is number 10 in the countdown because it breeds fast.
One female can have up to 16 babies in a single litter.
And she can become pregnant again the very next day.
All it takes to make millions of mice is a little nice weather and abundant
food.
So it╒s no wonder that mice just love the wheat belt of Australia.
In 1994, a single swarm of mice in South Australia caused over $65
million worth of destruction.
No wonder Australians hate these meeces to pieces.
Perhaps they could take a lesson from a small town in Germany that once
found an unusual way to get rid of rampaging rodents.
You can pipe the rats away.
I can, I have a very special tool for rats.
Show me at once.
Very well.
According to legend, a pied piper once used music to rid a town of rodents.
Unfortunately after a pay dispute, he took all the children as well, in a
story that could be more than just a fairytale.
Historical records from the German town of Hamelin, suggest that on June
26, 1284 a young piper really did appear in town.
Some speculate that the piper was hired to find settlers for new
colonies in Eastern Europe or perhaps he was recruiting for a crusade or a
battle.
Whatever the reason over 130 of Hamelin╒s young people left town that
day, never to be seen again.
He left behind only a blind child and a lame teenager.
A modern day pied piper could make a fortune in Australia getting rid of
swarms of mice.
Unlike the next contender in the countdown which is so popular, it can
attract swarms of humans.
All kinds of games are played on the beaches of California, including the
game of love.
While some come to soak up the sun and seek out a mate, these beaches are
also home to number nine in the countdown.
For at night, these beaches attract a different crowd.
These people are here to see an ***, but it╒s all in the name of science.
They are led by professor of biology at Pepperdine University, Karen
Martin.
Oh, oh, look, look over there. Did you see that one?
No, where are you pointing?
It╒s just came up with a wave and just went skimming back down, so that╒s the
first one.
That was one of the scouts.
Since we got to look her.
Well, let╒s let 'em get started, because we don╒t want to scare them
away.
These people are here to see a small fish called a grunion.
If anybody was coming to Southern California, I would hope they would
come at a time when there is a grunion run.
It╒s something you can see nowhere else in the world.
It╒s like no other fish in the world, that╒s an incredible sight to see an
animal that╒s fully aquatic, they are fully out of the water doing something
that╒s vital to the survival of the species.
The grunion is number nine in the countdown, because hundreds of
thousands of these incredible fish come ashore to mate.
First the females come ashore, digging in to lay their eggs.
Then it╒s the males turn as they fertilize the eggs in the sand.
Here the eggs can develop far from the mouths of hungry predators, until they
hatch two weeks later, when the next high tide washes over them.
I never have any shortage of people coming out to watch grunion with me.
People love to come and watch the grunion under the full moon.
People hold hands and walk up and down the beach, it╒s very romantic.
But not even the most hormonally charged undergrad can compete with the
grunion.
One female can lay more than 3,000 eggs on her trip to the beach and she
can spawn up to six times each season.
No wonder crowds flock to see a fish that really digs beaches.
It seems that for graduates and grunions, making out on the beach is a
spring rite that will never be wrong.
The next contender in our countdown of super swarm seeks safety in numbers.
Running in at number eight is the caribou.
In the frozen wastes of the Arctic, these large deer stick together in
large numbers for a very good reason.
Wolves know all too well, that caribou in a herd are hard to hunt.
There are always hundreds of eyes on the lookout.
So it╒s no wonder that caribou swarm all over the countryside.
In Alaska there are twice as many caribou as people and it╒s estimated
that the largest herds contain over half a million deer.
And this is a mob on the move.
There are so many hungry mouths in the herd that some caribou can travel
5,000 kilometers each year in search of new grazing grounds.
But some caribou need a helping hand.
In Scandanavia domesticated caribou are called reindeer and have been
linked to the fortunes of the Sami people for generations.
Jonna Utsi makes his living as a reindeer herder.
Each spring Jonna and his team escort their herd of reindeer 200 kilometers
from the arid interior to the coast, to fatten on lush summer grazing.
Unfortunately a recent snowstorm has covered the grass and a lunch of
lichen isn't enough fuel for the long trek through deep snowdrifts.
So some reindeer have to hitch a ride.
So far we have seen crowds of caribou, gallons of grunions and rascally
rodents.
But coming up is a close encounter with a ten-legged terror.
That's next on The Most Extreme.
In an increasingly crowded world, it can be hard to find a place to get
away from it all.
So that╒s why number seven in our countdown of super swarms has taken
privacy to the extreme.
This contender has gone to ground, deep underground.
Caves are perfect real estate.
They're safe haven because it can be hard for both predators and intrepid
explorers to force their way in.
Caves are quiet.
Caves are at constant temperature.
And caves can be close to water, but caves are also dark, very dark.
But that╒s no problem for the animal that╒s squeaking into number seven in
the countdown╔ is a bat.
The Bracken Caves in Central Texas shelter the world's largest bat
colony.
Twenty million Mexican free-tailed bats swarm all over the ceiling.
But there are some problems with living in such an extreme crowd.
Just trying to find your baby would be enough to make any mother a little
batty.
The other problem with living in a cave is the lack of sanitation.
So when bats go up stuff comes down.
This is a pile of bat droppings.
It's as tall as the Statue of Liberty some 90 meters high.
It becomes a mountainous meal for swarms of cockroaches.
And humans wanting a close encounter of the "***" kind.
In autumn, the bats leave the Bracken caves for Mexico and the cleaners move
in.
Huge vacuum pumps suck the bat droppings to the surface, where it's
bagged and sold as garden fertilizer.
But there are other crowds that also make a big mess.
Today, thanks to modern sanitation, most of us don't have to worry about
where our waste goes, but it's still a big problem.
It's estimated that if you collected all the human excrement produced in
one day and put it in the enormous Louisiana Superdome in New Orleans, it
would fill it to the height of a four story building.
The collected droppings of 20 million bats also creates a staggering stench,
which might explain why every night this crowd likes to get out for a
breath of fresh air.
This is one swarm that values its privacy, unlike our next contender, a
home invader that really gets under your feet.
Tropical islands are some of the least crowded places on the planet.
Unless you're on Christmas Island in the Indian Ocean home of number six in
the countdown╔ the red crab.
These crustaceans are all over the island like a rash.
Some 500 people share Christmas Island with about 120 million red crabs.
Fortunately, for most of the year the crabs live inside the forest.
But once a year, at the first sign of the wet season, the entire adult crab
population marches to the sea.
It's an epic 8 kilometer journey out of the rainforest, through villages,
across busy roads, and down cliffs to the beach.
The crabs that survive the week long trip, dip themselves in the water to
replenish their body fluids.
And then it's time to mate.
The red crab is number six in the countdown because an estimated 60
million sex crazed crustaceans swarm across the beach.
Then each female releases over 100,000 eggs into the water.
But crabs aren't the only ones living in extremely crowded real estate.
In England, the city of London is home to over seven million people.
This may seem crowded, but if the area of the city was divided into tennis
courts there would be one person per court.
But if you travel to Hong Kong, the living conditions are really crowded.
While the population is similar to London, the amount of available land
is so small that each tennis court would have to hold 25 people.
Red crabs certainly don't suffer from demophobia.
Even their babies stick together when they return to shore after a month at
sea.
Then they start their own march up into the forest, as part of a swarm so
special that it forms its own living red carpet.
Living in a swarm this big would be enough to make anyone a little crabby.
The story of the next contender in our countdown of extreme swarms begins
millions of years ago, in the islands of Palau south of Japan.
When a submerged reef rose from the sea, it created the landlocked
saltwater lakes that became home for the most unusual swarms in the
countdown.
Welcome to Jellyfish Lake.
Each day millions of jellyfish drift slowly from one side of the lake to
the other.
Safe inside their private pool, these extreme jellies have become
vegetarian.
They feed thanks to millions of microscopic algae growing inside their
bodies.
The algae collect sunlight and photosynthesize, creating an excess of
sugars and proteins which feed the jellyfish.
In return, they form a swarm of synchronized sun-worshippers.
Every day the jellyfish mass together to swim from one side of the lake to
the other, keeping out of the shadows.
However jellyfish aren't the only animals to have a mob mentality.
We like to think of ourselves as individuals, but there's some evidence
that when you put humans in a mob, a different psychology takes over.
We've all seen flocks of birds and schools of fish moving as one.
But next time you're in a crowd, watch how humans also move in synchrony.
One study has shown that crowds of people can move, jump and clap with
extraordinary precision.
Slow motion analysis has revealed that the hand clapping of one crowd was
accurate to less than 1/64th of a second.
Such is the power of mob psychology.
The synchronized behavior of the jellyfish is spectacularly impressive,
given that these simple animals don't even have a brain.
But then it doesn't take much thought to form a swarm.
Jellyfish are mostly drifters, congregating thanks to the power of
wind and current.
But our next contender has to survive an endurance ordeal that would cripple
any Olympic athlete.
The fourth contender in the countdown of extreme swarms hangs out in the
mountains of Central Mexico.
This is no ordinary forest.
And these are no ordinary trees.
Instead of leaves, they have butterflies, lots of butterflies.
There can be 20,000 on a branch and 220 million in a swarm.
And that's why number four in the countdown is the monarch butterfly.
This swarm has assembled in Mexico to escape the cold northern winter.
But the butterflies can't stay here, because they need to lay their eggs on
a plant called milkweed which only grows up north.
So come spring, it's time for millions of monarchs to move.
The monarch butterfly may look fragile, but it's no lightweight.
Entomologists have tagged individual butterflies and found that they can
travel at average speeds of up to 130 kilometers an hour and fly nearly one
kilometer high.
This is how over five generations, monarchs can fly as far north as
Canada.
But then in autumn, it's once again time to head south for the winter.
Monarch butterflies really are the ultimate endurance athletes.
Some individual butterflies can travel 5,000 kilometers.
That works out to be a journey of about 150 million body lengths.
If we tried running the equivalent distance, we'd have to travel around
the earth, 11 times.
Millions of monarchs may give human athletes a run for their money, but
they're no match for the billions of bugs coming up in the countdown.
So far we've seen a sky of butterflies and a sea of jellyfish.
But if you thought a swarm of crazy crabs was bad, coming up is a plague
of truly biblical proportions.
That's next on The Most Extreme.
We may be witnessing the beginning of an era that'll mean the complete
annihilation of man.
Annihilation?
The Beginning of the End.
Hopping in to number three in the countdown is the locust.
Movie directors didn't need to enlarge locusts to turn them into a
destructive force.
For what these grasshoppers lack in size, they make up with sheer weight
of numbers.
The locust is number three in the countdown, because a single swarm can
contain 40 billion insects.
These vast hordes threaten over 20% of the earth's surface.
More than 65 countries are at risk of invasion from an army that really
marches on its stomach.
A single swarm can eat 80,000 tons of crops a day literally stripping the
countryside bare.
But some countries have been invaded by other destructive swarms.
Back in the 13th Century one writer in a doomed city compared the approaching
army to a swarm of locusts.
It was the Mongol horde of Genghis Khan.
His name meant "Universal Ruler" and he went on to create the largest
continuous land empire in history.
He began by uniting the tribes of Mongolia.
Then he swarmed across the continent.
With each town he captured, his army grew until it was a quarter of a
million strong.
At its height, the Mongol Empire stretched from Hungary to Korea, and
from Siberia to Tibet.
Imagine the size of the empire if Genghis Khan could have traveled like
a locust.
For when these grasshoppers grow up they get wings.
Locusts can fly for 17 hours without stopping, traveling up to 5,000
kilometers to find food.
But even this plague would be completely overwhelmed by the next
contender in the countdown.
The cold stormy seas around Antarctica covers 20 million square kilometers.
It's a huge home for a huge swarm of tiny creatures.
Coming in at number two in the countdown are krill.
These miniature shrimps thrive on microscopic plants blooming in the
nutrient rich waters of the Southern Ocean.
They never get any bigger than your little finger, but if they stay out of
trouble, they can live for up to seven years.
And the best way to keep out of trouble is to stick together in a
swarm.
Swarms of krill are big, very big.
One swarm was estimated to cover more than 450 square kilometers and was
thought to contain 2 million tons of krill.
That's about the same weight as the entire human population of Canada.
Unfortunately for krill, they have another name.
They're sometimes called "Red Whale Feed" because a whale can eat an
African elephant sized portion of krill each day.
But back on dry land, there's another population that's rapidly forming a
swarm of krill like proportions.
There was a time when the human population grew only slowly.
Birth rates and death rates were about the same, keeping the population
stable.
But recently things have changed and the human swarm started growing fast.
To see just how quickly the human population has exploded, you need to
journey back in time.
For thousands of years humans were having lots of children, but losing
many of them before they turned five.
So by the year 1500, there were probably about 460 million people on
the planet.
Then along came the Industrial Revolution and the advancement of
science and technology.
The death rate started falling and our population started growing.
Our swarm has already become 12 times bigger than at the year 1500, and it's
predicted that by the turn of the next century we'll be a swarm 11 billion
strong.
While it looks like humans are taking over the earth, at least the sea
belongs to the krill.
It's been estimated that there are 100,000 krill for every single human
on the planet.
But even this enormous gathering is no match for the most extreme swarm in
the countdown.
We've seen the nine contenders.
They're the best of the best.
Only one animal is a more extreme swarming machine.
It's number one and it's coming up next on The Most Extreme.
Be warned. The most extreme swarm in the countdown is a lot closer than you
think.
A horde of billions have conquered Europe.
But it could already be too late to stop the empire from invading your
home.
Fighting its way into number one in the countdown is the Argentine ant.
These tiny terrors are becoming the most common household pest in the
world.
They can't sting but they can bite.
Their simple battle plan is to keep attacking until they overwhelm the
opposition.
But the ants also have a secret weapon.
Unlike other ants, colonies don't compete with each other, they
cooperate.
By working together, they're forming a super swarm to conquer the world.
Early last century, the first wave of invaders left their home in Argentina
by stowing away on ships bound for Europe.
The army of ants wiped out native species as they advanced.
Now there are billions of Argentine ants in millions of nests and they're
all genetically related.
That's why these ants are number one in the countdown.
Their empire stretches 6,000 kilometers all the way from Italy to
Spain.
It's the biggest super-colony in history.
The closest thing to a human super colony occurs once every 144 years in
India.
The Maha Kumbh Mela is the most sacred of all Hindu pilgrimages.
That's why in 2001, an estimated 70 million people visited Allahabad on
the Ganges River during the six week festival.
It was a time to cleanse the soul and wash away sins in the purifying waters
of the river.
This could be the largest human gathering in history, and could be
seen from a satellite orbiting over 600 kilometers above the earth.
At the end of the festival, the worshippers returned to their homes.
But the invasion of the Argentine ants will never end.
This swarm is sweeping the globe, even to remote islands in the Pacific.
They've even managed to invade a school playground in Auckland, New
Zealand, home of professional entomologist, Ruud Kleinpaste.
The thing that makes these Argentine ants so extreme is the fact that they
all recognize each other.
They're so closely related.
If I were to take this ant on an aeroplane with me and drop it off in a
playground somewhere in France lets say, chances are that the French ants
would say "Bonjour sister, nice to see you, welcome to France.
Why don't you join our big great European swarm?
Goes to show, these ants that cooperate with each other, they've got
other things to worry about.
They don't need to fight each other, they can concentrate on other things,
such as how to take over the world.
Perhaps we could learn a lesson from these tiny invaders.
Imagine how much nicer the world would be if the human swarm started to
cooperate like the Argentine ant.
For when it comes to swarming, there can be no doubt that the Argentine ant
really is The Most Extreme.