Episode 1 Nature's Weirdest Events

No matter how well we think we know our planet, the natural world still

has the ability to surprise us,

to shock us and maybe sometimes even

to scare us with its extraordinary events and bizarre behaviour.

And new technology means that nature's weirdest phenomena

are being caught ever more readily on camera.

So, we're going to bring you the strangest stories our world has to offer.

From the biblical swarm that took Lake Erie by storm...

That is really creepy.

..and the bears with a taste for the poolside...

There is a bear in my hot tub!

With the help of scientists, experts and eyewitnesses,

we're going to try and unravel exactly what on earth is going on.

First we're heading to America's Great lakes where some

very bizarre romantics are dying to find love, before it's too late.

The shores of Lake Erie on America's beautiful border with Canada

have always been a tranquil place of peace and quiet.

Until, early in the summer of 2010,

it became the setting for a swarm of phenomenal proportions.

This gas station is being attacked by...something.

And that lady won't even get out of her car.

It's like it's snowing.

A swarm of literally billions stretched over a mile inland

and for miles along the western shore.

Every surface, every inch of air was filled with winged insects.

That is really creepy.

Local resident Greg Stewart recalls the experience.

They were all over the wall of the city and I didn't know if I should even

get out of my car, it was that bad.

And as I got out, they started crunching under my feet.

Then, within days, they spontaneously started to die in their billions.

Seriously, a pile of bugs.

The drifts of dead bodies got so deep that the local authorities

had to use snow ploughs to unblock the roads.

And as they started to break down, they left another treat, too.

It smelled of motor oil and vomit.

So what were these insects, and what could have caused such an extraordinary plague?

Don Schloesser is an expert in the wildlife of Lake Erie

The big swarms are really the result of the life history pattern of the western Lake Erie mayflies.

They live in the mud for about two years and they grow and they moult.

About the middle of May, the first of June,

they all come out of the water at one time.

They mate, and then the females go back out into the water to lay the eggs.

And then the whole process starts all over again.

Mayfly spend about 99% of their lives

as aquatic larvae at the bottom of ponds and rivers.

They spend their time feeding and growing

until, in a cunning plan to avoid getting eaten,

they all emerge en masse to mate.

The first few are easy pickings.

But soon the sheer numbers overwhelm predators -

they simply can't make a dent in the overall population.

After about two days, there's a swarm,

a swirling swarm like a little funnel cloud that's formed by the mayflies.

And what happens is the females jump into that swarm, they are fertilized in the air.

Once they have mated, the male dies and the female heads out

over the water to release her fertilised eggs

before she too passes away.

The entire process takes just a matter of days.

Each year as the event comes to an abrupt end,

it's all hands on deck for the task of clearing up the dead.

But there is still a lot of questions surrounding their mass emergence.

When they come out is still a mystery to us.

We can't predict very well in that two- or three-week period

when they are actually going to be coming out.

Sometimes it is related to storm events,

sometimes it is related to rain events, but somehow

the mayflies all get a cue when they are down in the bottom of the lake.

But why are there so many in Lake Erie?

Lake Erie supplies the types of sediment that this critter likes to burrow into.

It used to have mayflies many years ago, then they went away for many years due to pollution.

Now they're back and they've come back with sort of a vengeance

in terms of the numbers and the abundances that we see come out of the water.

So this almighty insect orgy is all down

to a particularly perfect set of conditions.

The enormous size of the lake and its newly clean waters contribute to

a swarm so large that it can bring a whole city to a grinding halt.

Even though you might be able to choose your lover,

who you end up living next to is an entirely different matter.

Coming up next, we look at some stories where neighbourly understanding is essential.

We'll investigate the curious events that could lead you

to sharing your favourite spot in the garden.

But first, one incredible encounter that has led to a surprising

and beautiful Platonic relationship.

Churchill, on the shores of the Hudson Bay in the Canadian sub-arctic.

Each year, starving polar bears roam around town

waiting for the sea to freeze so they can hunt seals.

Dog breeder and Churchill resident

Brian Ladoon keeps 150 sled dogs on the shores of Hudson Bay.

Just a complete city of dogs.

Brian keeps his dogs on a spit of land jutting out into the sea.

It's isolated and the best place to keep Eskimo dogs on earth.

It's isolated and it's controllable, except for the other locals.

You see, one day in 1992, Brian watched helplessly as a starving

polar bear strolled onto his land

and headed straight for his dogs.

He knew all too well that bears

regularly kill and eat dogs when they come into contact.

When I first seen things playing out, I did have great concerns.

I was frightened, and I wasn't sure what to do.

He was unable to move a muscle as half a tonne of malnourished

mega-predator closed in on his faithful companions.

Then, as these photos show,

something truly unbelievable happened.

The pair began to play.

It is extraordinary to see them play together.

Actually you got a privileged position

when you are right in the front row seat and you're watching them

and they are only, like, metres away from you.

Amazingly this particular bear started an annual ritual,

returning to visit the dogs each year just before the sea freezes.

So why on earth did this hungry polar bear feel that

playing with its potential dinner

was better than satisfying its aching hunger?

Clinical psychiatrist Dr Stuart Brown has analysed these incredible photos.

What was amazing to me

was that the polar bear, as he approached this female sled dog

that was tethered, was in a predatory gait,

with fixed eyes, headed toward that sled dog.

Which anyone who's ever seen a predatory animal

recognises as a very powerful signal that says, "I'm going to kill you."

The dog went down into a play bow, and the bear immediately

picked this up, changed his gait and started dancing.

And was gambolling. The hair went flat, the eyes went soft,

and in a moment the bear was standing upright over the sled dog.

The sled dog was staying there wagging her tail.

They looked up at each other

and they started into this wonderful ballet of rough-and-tumble play

which went on for 20 minutes. It was magical.

Dr Brown is a world authority on play,

and has been studying its effects and benefits for over 20 years.

The smarter the animal, the more they play.

It's very important for survival

and for adaptation in a constantly changing environment and world.

Animals that are capable of play are also capable of innovation

and flexibility under unexpected circumstances.

Rough-and-tumble play, which is universal among social mammals,

is extremely beneficial, complex and very, very important.

What does it do?

It teaches the animal their own strength, speed, capabilities.

It puts them in competition with other animals,

tells them where they fit in the hierarchy of the pack.

It also teaches them empathy.

So that makes sense for animals of the same species,

but bears and dogs are competitors at best.

At worst, Brian's dogs are a tasty snack-sized mouthful for a hungry bear.

So there must be something more to it,

but what need could be more urgent than hunger?

I think the power of play signals is so intense

and so important for survival, of both birds and mammals

and human beings, that the signals that herald play are capable

of being interpreted across species, which is quite remarkable.

I've seen a magpie play with a bear.

And they each were able to interpret the signals between each other

that this was play, and they frolicked like crazy.

Well, that's really quite significant, and when you look

at that more deeply, you'll find that the survival drive that is a part

of each of those animals' survival drive, is linked to play behaviour.

So it seems that when the signals are strong enough,

the urge to play can become irresistible.

What's really incredible, though, is that this one exceptional bear

started to bring its mates back with it.

So what started out with just one rogue

doing something out of the ordinary, is now an annual social event.

Up to seven bears from the Churchill population have all

built relationships with Brian's dogs.

And over the years they have become local celebrities.

First you think that the dogs are being attacked, and then you realise

that, you know, he's holding his head in his mouth because he wants to.

You'd think the bear would be right in there eating the dog

straight away, but they have some kind of companionship going on,

and it's amazing. It beautiful.

They look like they are having a great time.

They are happy to see their buddy, you know?

DOG WHINES AND BARKS

I think the dogs get sad when they see the bears go in the fall.

They miss them.

But, you know, come a certain day, the polar bears leave on the ice.

Leaving the dogs hopeful that they will return next year to renew their friendship.

BARKING AND GROWLING

When you really take a close look at what's happening in something

just as magical as a polar bear and a sled dog, you begin to get

an understanding that there is something deeper going on here.

Incredible stuff. But, you know, in we humans,

play is far more important than learning how to survive in the wild.

It's also about learning empathy

and a great range of other social behaviours.

So, for we humans at least, play isn't just practice for hunting and fighting.

For our next story we look at some bizarre neighbourly

relationships that go way past sharing the odd cup of sugar.

The American black bear...

Shy and retiring,

they prefer their own company...

..foraging for berries and grubs in their favourite habitats -

the forests, marshes

and rugged mountains across North America.

They're brilliantly adapted to life in the wild.

However, some US house owners have been witnessing some very peculiar behaviour.

There's a bear in my hot tub!

Please don't pee in there.

Hey, get out of there! Get out of there!

And it's not just the odd individual taking a dip

Even fiercely protective mothers with cubs are getting in on the action.

I got them swimming in my pool. They use the pool more than us.

-Why didn't they go in Dr Bob's pool?

-I don't know.

But why would such a shy creature decide to party in a human's pool?

You have to call the cops, Daddy. You have to.

Bear expert Dr Ted Oakes believes that he might have an explanation.

Black bears spend all winter in dens, which are often very,

very cold places, and so they have thick, thick fur.

But in the summer, because the fur is black, the fur absorbs heat

almost like no other material, and they really, really heat up.

I remember somebody I work with stuck a thermometer in the fur

of a black bear in full sun, and it was just below boiling point.

It was about 80 or 90 degrees Celsius.

So, their first line of defence in the heat is to remove themselves from the sun.

The second line of defence in the heat is to start panting.

And black bears will pant when they are very, very hot.

But when a black bear is panting,

it's really in a situation where it's got to do something else

to cool down, and that's usually seeking water.

So, they take the plunge to cool off, but aren't black bears

shy and elusive animals that stay away from humans?

There are nearly a million black bears living in North America,

and 300 million people.

In fact, I would say now that most people are never more than

a few miles from a black bear in most parts of North America.

Black bears are rarely seen and the reason for that is they are quite shy.

They don't want to be around people. They like to avoid people and usually people are trouble for them.

But if there is not much food in the forest,

they will take the opportunity to find food near human habitation.

If it's a choice between starving to death and finding

food from humans, bears can sometimes come to town.

They might not actually come to a house to find water to cool down,

they might actually come to a house to find a bird feeder.

But once they are at the house and they see that the house not only has a bird feeder

but a swimming pool, that's when the party could start for a black bear.

Put that down! Quit tearing it up!

But there is something even more amazing about these intriguing beasts.

In some places where bears make trips into town,

they make sure they do so on bin collection day,

making their trips as fruitful as possible.

Having a caring approach for our wild neighbours isn't something

that's restricted to people living in far-flung places.

Yes, they might have bears in hot tubs, but we have foxes on trampolines.

There are about 250,000 adult red foxes in Britain...

..and just like black bears they're intelligent,

opportunistic mammals,

happy to treat our property as their own.

And occasionally use our gardens for a little play, too.

What all these weird relationships show us is that as our population

expands, it gets ever more important to treat those around us with a bit

of humility, whoever they are.

Even if it does mean some of us must accept that man

might not always be a dog's best friend.

In nature's weird world, it pays to have a good relationship with your neighbours.

For nature's next weirdly one-sided union, we look at a hitchhiker

that's desperate to dive deep into a long-term relationship.

Back in 2009, climbing expert Tim Fogg arrived back in

the UK from a trip to the Central African Republic.

Nothing odd to report, until one day this happened.

Suddenly my hand swelled up for no apparent reason.

Then it went down, then about ten days later my arm swelled up

and then it went down. Just bits of me kept swelling up.

As a rope access specialist, Tim has travelled to

some of the world's most bizarre and extreme environments,

but never before had his body parts randomly swollen

for no apparent reason.

This bizarre bodily behaviour continued for two years.

So what could be causing these spontaneous swellings?

After several medical tests, Tim was diagnosed as having

contracted Loa loa, or the African eye worm.

It gets its gruesome name from

the only time it becomes visible in infected humans -

as it passes through its host's eyeballs.

It's an incredible parasite that's carried by certain types

of day biting flies in the swamps of west Africa,

exactly where Tim had returned home from two years earlier.

I think I got it wading through a load of mud in the forest where

mango flies live, which is the thing that transmits it.

Infection occurs when the larvae of the worm

are passed to a human as the fly bites.

The larvae then develop under the skin until they become adults

and start their travels around the body.

As they move about under the skin, the immune system starts to

react and it's this that causes the swelling.

I guess it was in my hand to start with,

it presumably went up one arm then my other arm swelled up,

so presumably somehow it got right across my shoulder and down into the other arm.

Or maybe it was another worm. I have no idea.

Incredibly, the worm can grow to be seven centimetres long and live

for 17 years creeping around under the surface of the host's body.

The worst thing about this thing wandering about under your skin

is its habit of coming up to your eye

and wandering across your eye and across the bridge of your nose and into the other eye.

And that is apparently very, very painful.

And I did have one incident where the side of my face swelled up

which meant it was there, it was getting close

and thinking about going across my eye.

Luckily it changed its mind.

The beauty of this parasite is that it doesn't hurt you at all,

and it didn't make me feel ill.

It was just the swelling so it's very clever.

I mean, it just wants to feed off me,

it doesn't want to give me bother if it can, cos I might get rid of it.

After he was diagnosed in 2011, Tim's doctor put him

on an intensive course of drugs, and a year later in June 2012

he was deemed tentatively clear of his tenacious little body mate.

Our last story is more body burrowing than bunny boiling,

a gruesome but truly ingenious example of nature's

weird relationships gone bad.

And so to Panama where an innocent traveller has picked up

a couple of unwanted passengers.

Do you see it? Right there. SHRIEKING

What started as two small insect bites has become swollen and angry.

-SHRIEKING

-It's ready to come out.

-Yeah, it is.

And there was something inside.

Whatever they were simply had to be extracted.

They are big. I can feel it trying to pull back in. Gross.

-You mean it's still alive?

-GASPS AND LAUGHTER

That's huge!

So, what on earth are they?

Dr Mark Rowland works at the London School Of Hygiene and Tropical Medicine

and has travelled the world studying parasites.

Those insects that we are trying to pull out of people's bodies are

the larvae of the botfly and I have some here, pickled inside this jar.

They are quite large. They are about one and a half centimetres long.

But how does something this big get under your skin in the first place?

The botfly itself is quite large, it's about the size

of a bumblebee, so if it were to actually land on a host itself

it would probably be detected by the human or by the cattle or pig

and be brushed away.

That makes it less likely for the fly

to succeed in laying its eggs successfully on the host.

So the botfly has come up with a very sneaky tactic.

What the fly has cleverly done is to grab,

usually an insect like a mosquito or a tick or even a housefly.

After a quick air ambush, the botfly pins down the fly

and quickly attaches its eggs.

And then off it goes to do the botfly's dirty work.

On contacting the human, or animal host, the small botfly larvae inside the egg will be able

to detect the warmth of the host, and it will hatch at that point.

And it does this very quickly indeed.

The larvae is able to penetrate and embed itself

in the skin of the host.

Over the course of several weeks, it will grow

and eat its way into the flesh.

And just in case you were thinking of getting rid of it at that stage,

it has spiny bristles that hold it in

and make it impossible to pull out.

Oh, my God! Oh, God!

That definitely is the trick, man, overnight.

The only way to win this tug of war is to play dirty.

One trick that you can do to make it easier is to

smear a gel or fat over the rear end of the larvae.

This will block the breathing tubes of the larvae.

That makes it easier to actually draw the larvae from the body.

GROANING

SHOUTS AND GROANS

Only when you've cut off its air supply will the botfly let go.

Of course, the other option is to let nature take its course

and wait six weeks for the larva to become a maggot,

eat its way out and drop onto the ground before becoming an adult fly.

It's a nasty business, however they exit.

But after all of this, you should just end up with a little scar - no problem.

Amazing that a maggot that size does so little damage in the end.

From the worm that's just dying to get under your skin

and the botfly who knows how to play tough,

it's obvious that the further we travel the more likely we are

to bring home the unwanted baggage of a holiday romance.

What all of the stories in this programme seem to illustrate

is that a bit of understanding and tolerance help in all of our relationships.

So, if we can implement a bit of love and respect towards all of nature's wonders,

there's absolutely no doubt that the world would be a richer place.

And of course, the world is always getting smaller.

So as we welcome more and more of these bizarre creatures into our own back-yards,

what we think of as weird now

might be a lot weirder in the future.

Next time on Nature's Weirdest Events,

there's an island awash under a tide of tiny crabs...

..a town terrorized by rampaging elk,

and a community primed for an unbelievable invasion of insects.