Episode 1 Nature's Weirdest Events

We live in the age of information.

Events are transmitted to the palms of our hand

24 hours a day.

Events which surprise us,

occasionally even frighten us.

We're going to bring you some of the most bizarre and mysterious

natural phenomena on the planet.

From the Dutch car that got completely cocooned in a silky web,

-to the day that Sydney turned crimson.

-This is unbelievable.

And from the swarms and plagues sweeping the world,

to the mystery surrounding 200 whales in Tasmania.

Using eyewitness accounts, news footage and experts and scientists,

we are going to try and explain what on Earth is going on.

Right then, for our first set of weird events,

we're going to witness first-hand what happens

when creatures behave in bizarre and surprising ways.

There's an explosive event which shocked the residents

of a quiet Hamburg suburb and a parasite that will have you gagging.

But we start in the city of Rotterdam in Holland.

When, in 2009...

this happened.

It was like something out of a Grimms' fairy tale. Look at it.

The poor owner of this red Honda had something much worse

than a parking ticket stuck on his car.

And it didn't stop there.

Everything was entangled in this mysterious web.

A closer inspection revealed millions of the silk-spinning

offspring of a species of ermine moth.

So, what were so many caterpillars doing wriggling

over the surface of this thick web?

Well, Dr Ray Barnett is a moth expert from Bristol Museum.

Can he explain this extraordinary event?

The adult female, flying about at night, like most moths,

would find the right food plant

and then would lay a clump of about 50 eggs.

Tiny little caterpillars hatch out

and then they will start to move about and find some food.

And that's when they start to form webs.

The silk is made from proteins in the caterpillar's saliva.

It's both strong and sticky.

Normally, we see caterpillar silk being used to make a cocoon

for their transformation into an adult moth.

But in Rotterdam,

the ermine moth caterpillars had a totally different plan.

They spin this silk over the food that they're on

and hide underneath it.

And that just means that the birds, which are the main visual predators

of caterpillars, are unable to get at them easily.

And they're not the only creatures out to get them.

There's also a particularly resourceful parasitic wasp,

which lays its eggs on their skin.

Its larvae then feeds on the caterpillar.

It's in their interest cos they're nice and juicy and very attractive

for birds to eat, in particular, to protect themselves in that way.

The reason they chose this street in Rotterdam

is because it's lined with plenty of their favourite food.

The leaves of the Spindle tree.

But why was the web so enormous,

completely covering the trees from top to bottom?

What seems to happen when we get these really big aggregations

is that you've had several females lay eggs on the same plant.

And so, they're all joining together and making a, sort of, super web,

which can cover whole hedgerows if there's enough of them.

And, of course, as they get bigger they need more food

and so the web expands and increases.

Fair enough. But this still doesn't explain why they coated the car.

As they gradually exhausted the food supply, so, they continued to

look for more by spinning more web and expanding out and, perhaps,

leaving the tree that they were feeding on to try and locate more.

If you imagine yourself as a poor, little, defenceless caterpillar,

you can't just run across the road because the birds will eat you.

So, you have to keep your protection with you.

You have to keep spinning the web and moving underneath that web.

So, they're moving off the tree, they don't know where they're going,

but they're looking to try and find some more food plants.

And, consequently, they've ended up covering all the bits and pieces

around the tree, which happened to include, in this case, a car.

So, quite a remarkable incident. But I don't think they were fooled.

They didn't think this was something to eat.

They're just on their way to try and find more to eat.

So, the reason for this incredible car-cooning caterpillar event

was a bumper year for ermine moth, triggering a desperate race

for caterpillar food and a very sticky situation for the car owner.

What an astonishing spectacle!

It's almost a work of motoring and caterpillar art, I have to say.

Nevertheless, we are getting more reports of these things

and the time to look out for them is in May and June.

Especially, if you have Bird Cherry trees or Spindle trees

in your garden. If you do, don't park your car underneath them.

And we stay with unusual appetites for our next weird event,

which is truly amazing.

We're crossing the border from Holland to Germany

to the outskirts of Hamburg, where, in 2005,

a small pond became the focus of international shock and revulsion.

About a thousand dead toads were discovered lying around the edges.

Their bodies appearing to have exploded.

Eyewitnesses said they swelled up to about three and a half times

their normal size and then simply burst.

And they burst with such an explosive force,

that their entrails were blown over several square metres.

Nice(!)

The amphibians affected were European Common toads

and the carnage took place in April,

around the time when they were spawning.

Scientists initially thought that foreign racehorses

at a nearby track might have brought in a virus or an infection.

But when they tested the water and the toads,

they found absolutely nothing.

The location was dubbed the Pond of Death and then things escalated

as the deaths spread across the border to a nearby Danish lake.

What could possibly be causing these gruesome events?

Eventually, scientists came up with a theory

that implicated these types of birds

and placed them at the centre of this mystery.

You see, corvids, like this raven,

are amongst the most intelligent of birds.

If you want to know just how clever they are,

take a look at these extraordinary Japanese crows.

You see, they had some tough nuts to crack, walnuts to be precise.

They realised they needed some help.

So, they were dropping them

onto the road and using cars to crack them open.

Pretty brainy.

But retrieving them was dangerous.

So, these avian masterminds took it one stage further.

Just look at this.

They started deliberately dropping them onto pedestrian crossings

so they could collect the contents of the nuts

when the traffic stopped.

Come on, that is pretty clever.

But what have highly intelligent birds

got to do with exploding toads?

Well, when scientists examined the corpses of the toads,

they found a couple of interesting things.

Firstly, a tiny beak-shaped mark

just above where the toad's liver should be.

And then, when they looked inside,

they found that the liver was missing.

And what it appears that had happened

is that the local crows had learned to peck the liver out

through the body of the toad and thus avoid its toxic skin.

No-one knows how they learned where the liver was located,

but we do know that toad's skin is

so poisonous that many animals can have a fatal reaction to it.

But the liver is so nutritious, it's worth working out

how to extract it safely.

Now, when toads are attacked by predators, their natural response

is to swell up and make themselves as big as possible.

So, it looks as if they'd be impossible to swallow.

But, of course, with the liver missing

and without a diaphragm, those lungs just swelled and swelled

and swelled until, in the end, they simply exploded.

Clever birds, corvids.

So, the mystery of the exploding toads was finally solved

by smart detective work and it was the crows' refined taste

for toad liver that was to blame.

But if you thought those poor toads had it bad,

wait until you see what our next weird species gets up to.

For our final bizarre animal story, we're in the UK,

in Lewisham, south-east London.

A couple preparing a fish supper were horrified to find

this sinister-looking creature staring out of the fish's mouth.

Fishmonger, Donna Cawley, was also mortified when she found

one of these creepy-looking creatures in her fish.

I was absolutely shocked to see it cos I didn't know what it was.

It's just, it's not normal, really, is it? To go home

and find that in a fish's mouth.

They look like maggots to me.

Not very nice to look at all.

These animals are turning up in fish's mouths

all around the world and the reaction is always the same.

One of repulsion and loathing.

They look like an ordinary fish tongue.

It's segmented, looks almost like a beetle.

But if you look closely, it has little feet that move around

and the tongue looks like it's walking.

And the first time that we saw this, we were really freaked out.

So, what exactly are these things?

And why are they lurking in the fish's mouths?

Dr Tammy Horton is a marine biologist who has studied

these unsavoury members of the isopod family.

And their habits might make you gag.

All of these isopods have been called tongue-biters.

What happens is a larval isopod will infect

by crawling under the gill cavity and settle on the fish's tongue.

Now, it has very sharp claws that enable it to grip onto the skin

of the fish and to grip underneath the tongue and into the flesh.

It will stay there and grow by blood-feeding on the host.

So, it just chews away at the skin or part of the tongue

and starts to feed from the arteries of the fish.

I've seen parasitised fish with no tongue left.

So, the isopod itself becomes a replacement tongue for that fish.

The tongue is completely chewed away and eaten up.

You can see the seven pairs of legs,

each is armed with a strong dactyl, which is like a claw.

And it's these which the isopod uses to cling onto the fish's tongue.

They do cling onto your finger.

They grip on and you can hold them upside down

and they'll hold on with just one claw.

They're that sharp and that strong.

Although they cause quite a lot of horror, seeing something like this,

these are all members of the order Isopoda.

They're very wide-ranging, they live in seaweed,

they live on the seashore, they live in the deep oceans,

in trenches and also in your back garden.

You see, woodlice are probably the isopods we're most familiar with.

You can find them all over the world.

There are around 40 different species in the UK alone.

And when you look at them, the family resemblance

with the tongue-eating parasite is pretty obvious.

But these two also have a big brother.

The aptly named giant isopod,

a scavenger found at the bottom of our deepest oceans.

This animal can walk along the sea floor quite happily and quite fast.

Like the parasitic isopod, it has strong mouthparts

which can be used for crushing and tearing at flesh.

I wouldn't want to put my hands anywhere near this guy's mouth.

Impressive though this giant relative is,

it's the habits of the little tongue-biter called Cymothoa

that provokes the strongest reaction.

To me, to find one of these parasites inside a fish's mouth

is a moment of joy and elation because they're quite rare.

But for someone who is buying a fish in a fishmongers,

to find one of these is probably the complete opposite reaction.

It's one of horror and disgust.

Well, you might think, what a horrible thing,

but then, equally, you'd have to admit that

that tongue-biting parasite is a triumph of evolution.

All of the adaptations it's made to survive inside its host.

And when you think about it, it's easy to see where sci-fi writers get

inspiration when they want to come up with their next species of alien.

Each of these bizarre stories,

show the extremes creatures will go to just to find their next meal.

Whether you're cocooning a car in your hunt for leaves,

detonating toads by pecking out their livers,

or replacing your host's tongue as you drink its blood,

We might find them weird or repugnant,

but for the species concerned,

it's a perfectly natural solution to a problem. Top marks.

Now, if the little things in life can have so much impact,

wait till you see what happens when we move on to the really big stuff.

Our next couple of weird events are storms.

And I can guarantee you won't have seen anything like them before.

Coming up, we'll be finding out what made one of the world's

most iconic cities look like it was built on another planet.

But, before that, we travel to Switzerland

to the small town of Versoix.

This pretty Swiss quayside on Lake Geneva is popular with tourists

and, in the summer, it's an idyllic spot.

But on January 26th 2005,

the locals woke up to a surprise.

You see, overnight, their quayside had been transformed into a strange,

eerie and beautiful natural ice sculpture.

One local resident recorded what has to be

one of the most extraordinary dog walks they've ever taken.

Everything was coated in a thick glaze of ice,

up to ten centimetres deep.

Boat owners, well, they were left with a sinking feeling

as the weight of the ice had started to capsize their yachts.

And some car owners, anxious to retrieve their vehicles,

bravely tried to hack or melt them free.

So, what on Earth had happened to create this astonishing scene?

Well, the answer was actually simple.

You see, during the night, temperatures had reached minus ten,

not unusual in itself.

But, this combined with winds gusting across the lake

at 60 miles an hour, had produced something extraordinary.

The whipped-up waves and spray, hitting the quayside

on the south-western shore, simply froze on the spot.

And the results were nothing short of wondrous.

It was a good week before the ice thawed

and freed the entombed trees, benches and cars.

This was a true one-off event for the residents of Versoix.

A little bit of magic in the middle of winter,

something none of them would ever forget.

Incredible images. Haunting, like a vision from a Grimms' fairy tale.

But if those images chilled you, our second weird weather event

will have you gasping.

We're heading, now, to Australia,

to its largest and most famous city - Sydney.

On 23rd September 2009,

what happened to Sydney amazed the world

because it, literally, changed colour overnight.

That morning, everything was drenched in red.

It was almost like the colour of blood.

And I could see that it was throughout the city.

From his high-rise apartment,

Jonathan Berry had a ringside seat on these incredible events.

It was completely even. It was almost as if

I was on Mars.

It was very still, there was no wind and I couldn't taste it

and I couldn't touch it and I couldn't smell it. There was nothing.

Ten past six in the morning

and it's September 23rd 2009.

Sydney-siders grabbed their cameras and phones

and recorded the surreal scenes.

This is unbelievable.

Absolutely amazing.

6:30 in the morning. Look at this.

I woke up and I was, like, what is going on?

This is like the Apocalypse

or it's like Armageddon has actually hit Earth, you know.

It was just out of this world, it really was.

Nate Johnston documented a bizarre commute to work.

This is seven o'clock in the morning.

It was really eerie.

I catch the same ride, you know all the scenery and not being able

to see what's in front of you, yeah, it was almost a bit freaky.

7:20.

The fact that the visibility was reduced to about 15,

20 metres in front of you.

I couldn't even see the Harbour Bridge

until we were practically under it. It was really weird.

What had happened?

How did Sydney become like the surface of Mars overnight?

Well, the answer lay 2,500 kilometres away,

deep in the heart of Australia's outback.

Dust. Iron rich and deep red.

This is what had caused Sydney's extraordinary transformation.

Here, dust storms are just part of life,

but this event was, really, on a totally different scale.

Hardened Aussie, John White, has experienced

most of what the outback had to throw at him.

The dust storms that I normally come across are fairly short-lived

and you can see them coming.

There's normally a beautiful, blue sky and then you can see

the dust storm coming towards you.

It comes through, maybe a half hour or so, it's there.

And then, sometimes, you get a bit of rain and then it clears up.

While crossing a track, he had an accident at just the wrong time.

Shortly after, a storm, unlike anything he'd ever seen before,

overwhelmed his stricken vehicle.

The wind was absolutely atrocious.

The airborne sand, you couldn't stand up in it.

It was coming into your skin, even with my big beard,

you could feel it on your skin.

It was absolutely horrendous.

Atmospheric scientist, Craig Strong,

is an avid connoisseur of dust storms.

I reckon a good dust storm is one you can taste.

You know, so, you can taste it in your mouth,

you can roll it in your teeth.

And you can say, yeah that's about ten microns in size.

You know, that's a good dust storm for me.

Craig predicted its arrival.

He'd been watching events conspire over the weeks

and months leading to the storm.

We had floods in January, bringing sediment

into the inland parts of Australia.

We had droughts in the arid and the semi-arid areas of Australia,

putting the vegetation cover under stress.

And then, we had a really intense cold front move through,

which created very strong winds.

All the conditions were right

to produce an incredibly large dust storm.

16 million tonnes of frenzied dust

was now being whipped into the air.

At the height of the storm,

visibility where I was, round the track, was less than a metre.

And if I had have walked over the sand dune,

I can just about guarantee I would never have found my way back

to the truck.

At source area, the wind speeds were up around about,

they varied from 70 to 90 kilometres per hour.

It feels like sandpaper.

I had my beard pulled up over my nose

and eyes and just trying to protect my face when I was out in it.

Yeah. It was unbelievable.

This was the mother of all dust storms.

600 miles long and 300 miles wide.

A monstrous cloud the size of Spain rolling across Australia.

As it travelled across the country,

stunned Australians recorded the incredible spectacle.

'Absolutely amazing.'

-'It's not moving.

-I can't believe it's just coming across.

-'Yeah, I'm recording it.

-OK.'

-'Holy

-BLEEP.'

'It's going to get really dark soon, isn't it?'

What was amazing about the amount of dust we were seeing

was just how dense the dust was, you know.

The visibilities were roughly about one kilometre.

Now, to put that into context, you would have to go

to the source areas, normally,

to get that sort of level of dust concentration.

'It just got blacker.

'Oh, my gosh. I think we better go inside.

-'Yeah.

-Oh, that is horrible.'

When it reached Sydney, less than 24 hours later,

the intensity of the storm stunned everybody.

From country to city, people woke up this morning to an eerie, red haze,

the likes of which many had never seen before.

It was all due to a dust storm.

Everything is red. So, if you look around the streets, it's just red.

I mean, this isn't some sort of camera error.

I mean, that's what everything looks like.

Do you know the thing?

Radio stations keep playing music that's related to dust.

So, we have Dusty Springfield

and Slim Dusty all blaring over the radio this morning.

MUSIC: "I Just Don't Know What To Do With Myself" by Dusty Springfield

Dust storms are not unusual in Australia.

But this was by far the biggest since records had begun.

It had also travelled the furthest and caused the most disruption.

It was phenomenal, you know.

Being able to witness such a phenomenon, it's...

I don't think I will in my lifetime again, to be honest.

I've never seen anything like this at all.

I know that there are dust storms in South Australia and Western Australia

and in the centre, but that's a long, long way away from Sydney.

Being here when the dust storm rolled through was really...

it was quite a privilege, you know, it was really quite exciting.

We now realise that we're actually sitting on the edge

of a very large desert and we can, as city dwellers,

be impacted by these very large dust storms.

To realise that I was out in the start of that...

..it was amazing to think that, where I was, that storm went that far.

Yeah, it was absolutely phenomenal.

So, that dust had travelled 1,500 miles from Sydney.

But, you know what, our nearest desert, the Sahara,

is the same distance away.

Once in a while, an easterly wind will blow a sand storm out

into the Atlantic, where a westerly wind will pick it up

and blow the dust to the UK.

So, although we don't get storms of that magnitude,

even here in the UK, the Sahara Desert makes itself felt.

And we can see it. Dust all over our cars.

Now, one-off, weird weather episodes like these are awe-inspiring.

But a 2011 report on climate change predicts that there's going to be

an increase in what they're calling "unprecedented extreme weather".

So, as atmospheric conditions become more erratic, amazing events,

like those in Versoix and Sydney, may well become more frequent.

Now, the next weird events we're going to bring you

have unusual weather as their root cause with results that are,

for many, the stuff of nightmares.

It's plagues and swarms.

From the beetle invasion on a remote Colorado mountain

to a plague truly the size of Wales, creating havoc in its wake.

We're back in Australia with an animal hated by humans

the world over.

It's 1993 on a farm in southern Australia

and a desperate farmer is battling a mouse plague

of biblical proportions.

Oh, they're in my boots. Oh!

She's determined to save the pigs

she knows are besieged in the shed by hundreds of thousands of mice.

Oh, yuck. Oh.

Mice which are so desperate for food,

they're literally trying to eat her pigs alive.

That was 18 years ago

and set a world record for the worst mouse plague ever recorded.

But, unfortunately, for farmers all across southern Australia,

2011 is looking like it's going to be

another terrible year for mice.

New crops have been devoured across South Australia, Victoria

and Western Australia in the worst mouse plague in almost two decades.

Ian Cass from Loxton, South Australia...

..is on the front line of this latest plague.

He keeps 650 sheep on his farm.

Feeding that many animals keeps him busy enough.

The problem for Ian is that he's also, inadvertently,

feeding millions of tiny mouths.

Oh!

We've tried poisoning them.

We've tried all sorts to try and cut their numbers.

Over here, quick. Look in here.

Death by numbers in here.

Nothing works. We can't beat them. We've killed millions.

But we can't beat them. They're are a nightmare.

Oh, yuck.

And here are the stats.

A mouse eats up to a third of its body weight every day.

That's about eight grammes.

Not a lot, you might think, but when you multiply that

by the estimated half a million plus mice

which are living on Ian's farm, they could consume

one and a half metric tonnes of grain every 24 hours.

In this part of South Australia, they've been used to mouse plagues,

every six years or so.

But, recently, it's been more like every four.

Not surprisingly, they seem to tie in with years

when there's a bumper harvest.

But this is not the whole story. Greg Mutsy is a pest expert.

He's been studying Australia's mouse plagues

and is shocked at recent events.

It's been very severe

and the population densities in the paddocks have been terrifically high.

Perhaps, a thousand mice per hectare across vast areas.

There would be fewer than ten per hectare when things are normal.

Now, there's more than 100 times that number.

Mice have a fairly well-defined seasonal breeding pattern.

They start breeding when the crops mature in September, October.

They breed until the crops are harvested.

Then, they feed on whatever grain is spilled at harvest.

At that time, they run out of food, they stop breeding.

They usually have a population crash.

Greg thinks that part of the problem is that changes

in the way farmers grow and manage their crops now mean

there's more food left in the fields

during, what should be, the lean times.

So, why was 2011 such a bumper year for the mice?

This last season, we had a fantastic season.

We had above-average rainfall and exceptional, exceptional crops.

It was really good.

There was plenty to eat and this, combined with a mild winter,

meant perfect conditions to kick-start a plague.

They can breed at six weeks of age

and pump out a litter of about six every three weeks.

And, usually, very few of them survive.

But, during these mouse plagues, because of the abundance of food

and the fact that they outnumber the predators so vastly,

you get much higher juvenile survival.

And the rate of increase in the populations is dramatically higher.

-Oh.

-BLEEP.

Now, mouse plagues are strange enough in themselves,

but there is something particularly weird about them.

The strange things about house mice is that, although they've got

almost a global distribution now, the only places where they cause

these massive mouse plagues appear to be in Australia and in Western China.

So, let's get this straight.

There are house mice all over the world.

But what's extraordinary is that they're only plaguing

in two countries.

Why? Why would this be happening?

The reasons are still a mystery,

but, in Australia, it could be partly due to the fact

that house mice are an invasive species,

introduced by European settlers in the late 1700's.

Back home, they're a key component of a long-established ecosystem.

And they provide food for some of our most iconic hunters.

But, here in Australia, they have few natural predators

and little direct competition from the local wildlife.

So, when conditions are right, nothing can stop them.

Except, perhaps, man.

Mouse plagues have become a part of the landscape in Australia

and have been for a long, long time.

Well, there was a massive mouse plague in 1917.

Three and a half tonnes of mice

that were captured in one night around a single grain stack

in Western Victoria during that period.

These days, there isn't the manpower to kill them by hand

and Ian has to resort to poison.

Now, I'm never keen on killing animals but here, I have to admit,

there really isn't much choice.

I estimate, and it's only my estimation,

that we'd have to have killed well over a million out here already.

You're, sort of, starting to see

bodies starting to appear on the ground.

But there are some unpleasant side-effects.

How do you describe the smell of a million dead mice? It stinks.

The events of 2011 have equalled Australia's worst-ever mouse plague.

They're munching their way through

an estimated billion dollars of grain.

Horrific times, there, for those Australian farmers,

but I have to tell you, things are very different in the UK

when it comes to house mice like these.

You see, they've been so relentlessly persecuted by man

that they're no longer very common.

So, if you have a mouse in the house these days,

it's far more likely to be a wood mouse

that's come in from the garden.

You can tell them apart easily.

Wood mice have much larger eyes, larger ears, a longer tail

and they're perfectly white on their underside.

So, whilst they are plaguing in Australia, in UK homes,

house mice are in short supply.

For our next weird animal event, we feature a little creature

with an altogether more endearing public image.

The colourful, little ladybird.

Loved by gardeners because of their enormous appetite for aphids.

Their popularity is reflected in their collective name -

a loveliness of ladybirds!

But, in America in 2009,

visitors to the mountains of Colorado were confronted with this.

We came upon a tree that looks like it has red bark.

Only thing is, that ain't red bark.

It's certainly not.

And not so much a loveliness, more of a smothering scarlet-ness.

Tens of millions of these little, crimson beetles were crawling

all over the trees and plants.

Visitors and residents, alike, were confused

by the sheer scale of the ladybird invasion.

Oh, my God, they are everywhere.

They're going to start attacking us. This is unbelievable.

You can see them all over here, covering the trees, the rocks.

Looks like somebody's just taken a bucket of tomato juice

and splashed everything.

From the mountains of California to the Rockies of Colorado,

it's normal to see ladybirds gathering together in August

to mate and then to hibernate.

But this gathering was on an unprecedented scale.

So, what was going on?

Well, it turns out that 2009 was a red-letter year

for these colourful, little members of the beetle family.

A wet spring followed by a soggy summer,

meant a bumper year for aphids.

These tiny insects reproduce at an alarming rate.

And more of this ladybird food means more ladybirds, lots more ladybirds.

By 2009, in August, ladybird numbers had reached astonishing levels.

The resulting massive mating and hibernation gatherings

were truly a unique and wonderful spectacle.

But the next weird gathering of insects is not so benign.

In fact, it's one of the most destructive forces

in the invertebrate world.

We're back in Australia,

where, in 2010, the country was hit by a plague,

which was both uncontrollable and unstoppable.

Swarms of locusts are sweeping across rural areas

in the Australian state of New South Wales.

Up to one billion locusts in a swarm, moving over an area

twice the size of the UK, were sweeping across

parts of southern Australia and creating mayhem.

Ow, ow, ow, ow.

My friends and I, just, we saw this big, well, it was kind of

a brown cloud and we thought, like, it was going to rain or something.

But we stepped outside and, like,

we stuck our hands in it and there were just locusts.

At Irymple Primary School near the outback town of Mildura,

the kids were enjoying their playtime when the swarm hit.

There were millions.

100 million.

Billions.

Probably trillions.

Like, lots of them.

It just felt disgusting.

Mostly all the girls were just, "Aaaah."

But it wasn't just the kids whose playtime was being disrupted

by the millions of winged visitors.

Local sporting clubs are at their wits' end too

as the interlopers crowd their bowling greens and fairways.

From tennis courts to golfing greens,

anywhere with a bit of grass was fair game.

In Mildura,

the local football team were forced to take on two different opponents.

But, whilst the locusts were causing chaos in the town,

it was altogether more serious out among the farms.

Here, the locusts were not just an inconvenience,

they were a devastating force.

Professor Simpson is one of the world's leading experts on locusts

and knows all about their destructive power.

They eat, each day, about their own body weight in food.

And when you multiply that single locust by hundreds of millions

or billions, you can get the sort of devastation that we see.

But what's really weird about locusts is

that they all start life as a harmless, little grasshopper,

one who shuns company and prefers a solitary life.

It's true. They prefer to be on their own.

So, what could possibly change them

from shy singleton into a veracious, gregarious plague insect?

When conditions favour a large build-up in population,

for example, after rain, and then they get brought together by food

and their environment, they flip from being shy, solitary animals

into being actively aggregating, potentially swarm-forming creatures.

And we wanted to know why do they do that and how do they do that.

That's the key to being a locust,

rather than being a normal grasshopper.

The prof had a theory that it was something to do with being

in close contact with other locusts.

And so, they set about testing this theory in a rather unusual way.

So, we sat for many, many hours in hot rooms,

tickling locusts on different body parts with a paint brush.

And then, measuring their behavioural change as a result of that.

And we found that touch alone can cause a locust to switch,

very quickly, into the swarming form.

They found that the touching releases a hormone

similar to serotonin, which we associate with pleasure.

And it's this which triggers the change from grasshopper to locust.

But our locust are just wingless hoppers at the moment.

And they move across the country as a kind of marching, hopping army.

After five weeks, their wings are finally ready.

So, now, the locusts can take to the air

and are capable of covering vast distances.

And, for the farmers, this is the start of the real nightmare.

These airborne swarms have become unstoppable eating

and breeding machines.

And, frankly, nowhere is safe.

On the outskirts of Mildura, farmer Terry Bavidas

had everything to lose as the swarm approached his farm.

We'd had a very good start to the season.

My hay was about six inches high.

I came home about ten o'clock one morning for a cup of coffee.

And I walked outside and there was just this humongous plague

of locusts just outside and I didn't know where they'd come from.

And I knew straight away my crop was going to be decimated.

There was about five or six locusts hanging off each strand of hay.

By four o'clock that afternoon, they had decimated about 12 acres.

It's just not funny at all.

But Terry wasn't going to get mad, he was going to get even.

A friend of mine had found an exhaust fan out of a paint shop

and I've got it rotating at 290 kilometres an hour.

I had to pinch the kids' go-kart motor to do it.

Terry had created the Locust Muncher.

And it was payback time.

I was getting rids of hundreds, hundreds per second.

I couldn't tell you how many.

A friend of mine, Mickey, called me the Nutty Professor.

Every single person that went past laughed their head off.

So, hey, it works.

Terry's Mad Max solution might have helped to save some of his crops,

but the plague continued, moving relentlessly across the country,

gobbling up field after field of precious crops.

Meanwhile, back at Sydney University,

Professor Simpson had made a remarkable

discovery about what was driving their insatiable appetite.

The locusts were actually craving protein.

And the nearest source of protein,

within a locust swarm,

is the locust in front of you.

So, cannibalism drives mass migration in these swarms.

They're on a forced march, if you like,

to avoid being someone else's lunch,

but chasing the lunch in front of them.

The cannibalistic tendencies of these insects did little

to endear them to the residents of Mildura,

who were capturing their locust encounters on camera.

-Driving and it's hard to tell the road from the locusts.

-Yeah.

My mum hated that because she'd have to get a car wash,

like, once a week cos of those locusts.

The dogs liked them.

Cos when they splattered on the car they just licked them off.

Australia's 2010 locust plague lasted 12 long months.

It covered 190 thousand square miles.

And, apart from the inconvenience,

it was estimated that it cost farmers two billion dollars.

It's not surprising those locusts cover such vast distances.

What more motivation would you need than your nearest neighbour arriving

and then turning cannibal to eat you?

We'd all move on, wouldn't we?

The trigger for all of these plagues was an abundance of food.

The mice benefited from a record harvest.

For the ladybirds, it was a wet spring

that meant huge amounts of aphids.

And the locust benefited from a bumper start to the growing season.

When these tiny creatures mass together, they become greater

than the sum of their parts, often with dramatic results.

For our final weird events, we're heading down to the beach,

where we'll be seeing what happens when sea creatures end up

in the wrong place at the wrong time.

From the crabs that were found in their tens of thousands

on a UK beach,

to the baffling event involving 200 whales in Tasmania.

But we start in the UK,

where, in 2010, visitors to a West Country beach were greeted

with a scene of total devastation.

Starfish were lying dead in their thousands,

for no apparent reason.

These familiar sea creatures are not actually fish at all.

They're echinoderms, related to sea urchins.

So, they're unable to survive for long out of the water.

But what on Earth caused this many to wash up, dead, on a single beach?

The answer lay in an unfortunate combination of events.

You see, the starfish had just been mating.

Each female produces up to 65 million eggs in a season

and they prefer to do this in shallow water.

The starfish were weakened after breeding

and a nasty Atlantic storm simply washed them up onto the beach.

Battered and exhausted,

they were unable to make their way back into the sea.

So, they dried out and died.

The sad result was, actually, totally natural.

But, nevertheless, was upsetting for everyone who witnessed it.

Staying in the UK, just ten months later, on January 4th in 2011,

Thanet in Kent played host to another grisly scene.

This time, the bodies of 25,000 velvet swimming crabs

literally carpeted beach.

Now, there are over 5,000 different species of crab in the world.

They all use gills to breathe.

But some can live on land as well as in the sea.

But velvet swimmers are strictly underwater species.

And being on the beach is a death sentence.

So, why on Earth did thousands end up like fish out of water,

lying dead all over the beach?

Well, unlike the poor, old starfish,

the answer lay not below the water, but above it.

Britain was in the grip of an unusually cold winter

and the weather was having a chilling effect on the ocean too.

The crabs simply couldn't cope with the severe cold

and died of hypothermia.

Admittedly, not a pleasant end for them, but it was a lifeline

for the seabirds who were also suffering in the cold temperatures.

Fortunately, for both the starfish and the velvet swimming crabs,

numbers recovered very quickly

and there were no long-lasting effects on their species.

For our final weird event,

we're heading into uncharted waters with some much-loved creatures

whose lives hold so much fascination for us,

but also many mysteries too.

Whales are found in every ocean on the planet.

The size of their brains rivals that of primates.

These are complex creatures, which have evolved to navigate

our seas and make epic migrations.

So, why on Earth would such an animal do this?

'The Northern bottlenose whale remains some distance up river.

'The time for rescue teams to move in is getting ever closer.'

January 19th 2006 and all eyes were on London

as a Northern bottlenose whale turned up in the Thames.

Rescuers battling to save

the whale stranded in the Thames

say the next few hours will be critical to its survival.

This creature would normally be found in the depths

of the North Atlantic.

So, what was it doing in the middle of our capital city?

It's likely that this young adult had simply got lost

and was trying to reach Atlantic waters.

But heading west up the Thames wasn't going to get it anywhere.

Rescuers eventually stepped in and winched the distressed

and exhausted whale onto a barge.

We're now moving it out into the centre of the Thames.

CROWD CHEERS

The crowd, obviously, is going crazy because it's been a long,

long ordeal here for the poor creature.

But, despite their best efforts,

on the journey back down the Thames, the whale sadly died.

Now, an individual animal making a mistake is one thing,

but we are now heading to the Southern Ocean

and to the island of Tasmania where, in 2009,

a whole group of whales stranded on a quite horrifying scale.

Rescuers are, tonight, trying to save the survivors

from another mass whale stranding in Tasmania.

It was March 1st

and almost 200 whales were piled up along the Tasmanian beach.

These scenes on King Island were horrible.

Many already lay dead in what was

one of the largest mass strandings of whales ever recorded.

Volunteers flooded to the beach

to try whatever they could to keep the remaining animals alive.

So, what could possibly cause such creatures to commit,

what amounts to, mass suicide on the beach?

What we can say with some certainty is that there are 85 species

of Cetacean in the world, yet only ten of these regularly strand

in any numbers. This starts to tell scientists something about

why these events might happen.

In the UK, whale rescue is coordinated

by the British Divers Marine Life Rescue and run by Stephen Marsh.

One whale species that seems predisposed to stranding,

to mass stranding, is the pilot whale.

Pilot whales are called pilot whales because they follow their leader.

What happens is that they will follow one animal

wherever that animal goes.

If that animal has problems and goes up onto a beach,

the rest of the animals will try to go with it as well.

The fact that these are highly social animals helps explain

the large numbers, but it doesn't answer what on Earth causes them

to go on, what amounts to, a death wish.

That's where, frankly, it gets complicated.

There are many theories, but none that could explain every incident.

But one clue could come from the fact that unites

all of the species that mass strand.

They all use echolocation.

In Tasmania, at the Australian Antarctic Division,

Nick Gales is a marine mammal specialist,

who studies whales in the southern waters.

Effectively, if you like, you could have a group of animals

that are quite used to living offshore.

So, they're very, very skilled at living

beyond the continental shelf of the various continents.

They feed out there.

Occasionally, their prey will come in very shallow

and that brings them into the coast.

You get storms and it stirs up the water.

And while it looks very obvious to us,

standing on the beach, that there's a big beach there,

if you were to put yourself 50 metres offshore with a face mask on,

swimming around,

and not look above the water and get a clear picture,

it's very easy to get disorientated.

And, even though these whales have fantastic underwater sonar,

when it's very rough and there's a lot of sand in the water,

they're, effectively, semi-blinded.

Also, with these whales relying on echolocation to navigate,

the inevitable question is,

does human activity in our seas have a role to play

in causing them to come ashore?

Man has a habit of putting barriers in front of

a lot of sea creatures and one of those is acoustic pollution.

This can be caused by military activity, where they're out there

hunting submarines or using sonar at the same level

that whales and dolphins are going to be communicating at.

For them, it must be like sticking your head inside a loudspeaker.

We're muffling the sound

and we are creating something that's really going to frighten them.

But how much blame can be pinned on human activity is debatable,

because mass strandings have been reported for centuries,

long before we pumped noise into our oceans.

Whilst we don't understand all of the reasons they come ashore,

once they're here, it's a race against time

to get them back into the water.

Amongst the volunteers who help rescue whales in Tasmania

is Kris Carlyon.

There is a lot of death and that's quite hard to deal with.

But that one animal that you get back in the water

and released and successfully watch it swim away, it's pretty special.

But is returning them to the ocean actually the right thing to do?

Can they really survive after all of the trauma they've suffered?

Marine biologist, Rosemary Gales, heads the Tasmanian rescue team.

And she's done some pioneering work which gives the rescuers hope.

Over a year ago, we deployed some satellite transmitters

on some pilot whales that we released up in the northwest of Tasmania.

And we put five out and then, over the next month, we followed

those animals via satellite and also followed it up with an aerial survey.

So, we flew on them. Obviously, with the satellite links

we knew exactly where they were.

And it's one of the most exciting things ever

to have seen them all free-swimming in Bass Strait.

To actually know that they are OK and they did behave

like free-swimming whales was... It just vindicated all our efforts.

It's a fantastic result.

This groundbreaking study is fantastic news.

Scientists believe that if a whale can survive the first fortnight

after a stranding, then the chances of long-term survival are very good.

And with satellite tags deployed, we can start to learn more

about the movements and behaviour of these giants, out in the oceans.

And, perhaps, finally start to unravel some more of the mysteries

surrounding their lives.

Whether it's rough seas throwing up weakened starfish onto a beach,

sub-zero temperatures giving crabs a fatal case of hypothermia,

or the tragic stranding of 200 pilot whales,

when things go wrong in the sea, our beaches are often the places

where we get to unravel the mysteries and pick up the pieces.

What all of these stories prove is that nature's weirdest events

still have the power to shock us,

to stop us in our tracks and have us stare in awe.

And whilst many of these phenomena are explained,

many remain a mystery.

And there is one thing for certain and that is

that nature still has plenty of surprises just waiting to happen.

Next time on Nature's Weirdest Events...

Incredible holes open in the Earth's crust.

There's a frightening mystery in Arkansas...

What makes that happen? For them just to drop out of the sky like that.

..and a massive surge of sea foam

gives beachgoers a day they'll never forget.

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