Episode 3 Nature's Weirdest Events

However well we think we know our planet, the natural world

still has the power to surprise us, to shock us, sometimes even to

scare us with its extraordinary events and bizarre behaviour.

Given modern technology, nature's weirdest phenomena are frequently

caught on camera wherever and whenever they occur, and this means

that we can bring you the strangest stories our world has to offer.

From animals that keel over at the first sign of trouble,

to bears grabbing a takeaway.

And a pigeon-snatching predator from the deep.

With the help of eye-witnesses, experts and scientists,

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

The natural world can astound us with intriguing behaviour and

extraordinary designs, and in these weird events,

nature seems to have torn up the blueprint altogether

and come up with something truly bizarre.

Welcome to the world of nature's weirdest designs.

We're starting with the animals whose design appears to have

gone wrong right at the drawing board.

This is the stuff of myths and legends,

creatures so strange, they have to be seen to be believed.

From a lobster that looks half-baked, to a snake in two minds.

But first, we're off to the USA to meet some animals that may

look normal, yet something is making them act very strangely indeed.

Healthy looking goats that appear to drop down dead at the drop of a hat.

Oh, no, I've killed my wife's goat!

When the farmer Gene McNutt and his family moved to the peace

and quiet of Tennessee, they had no idea of the strange events

that would befall them.

We moved here to Tennessee in 1988.

My wife immediately wanted a new goat.

One of our neighbours was kind enough to bring her home

a six or eight week old goat and that goat became the pet of the house.

The McNutts adored their pet goat,

but then Gene had a very unnerving experience.

One day, the goat falls down and looks like he's gone stiff with

rigor mortis and I say, "Oh, no, I killed my wife's goat."

"What have I done? Has it had a heart attack?"

I'm standing there just in total amazement,

trying to figure out what am I going to do.

Had Gene suddenly developed the power to kill goats

just by looking at them?

Well, no.

Suddenly the goat wriggles a little bit,

gets up and walks off as if nothing had happened.

I decided to say nothing to my wife about it

since the goats appeared to be OK.

I asked the neighbour about the goat

because it was something that had never happened before,

and he says, "Oh," he says, "Those are just old nervous goats."

He says, "They're from around here."

Gene's experience wasn't a one-off.

These goats of the Deep South have a tendency to head south,

and then rise again unharmed.

So what's causing the goats of Tennessee to keel over,

only to be resurrected shortly afterwards?

Well, there could be a clue in what triggers their downfall.

Almost any noise that is unusual will cause the goat to stiffen

or fall over and it'll stay in a fallen position for 30,

45 seconds and sometimes even up to a couple of minutes.

Shirley's down.

Sometimes just a quick movement by a person will cause the goat

to fall over.

Almost every morning when I feed the goats,

at least one of them will fall out

and all I'm doing is pouring feed out of the bucket.

So, stress or excitement seems to be a factor in falling over.

When threatened or surprised,

many animals have a fight or flight response.

Their muscles suddenly tense up, as they prepare to run away or attack.

Freezing for a moment is part of a vital survival strategy

for some wild animals, but it seems that these goats in Tennessee

have a glitch in their system.

Instead of freezing for just a split second, they completely seize up.

This unusual reaction is unique to a particular breed called

fainting goats, although they don't actually lose consciousness.

So what makes this happen?

Well, it's all down to a genetic disorder called myotonia congenita,

and it affects how their muscles work.

The muscle fibres contract as normal, but then they don't relax

afterwards as they should, so these goats become temporarily paralysed.

It's a condition that they learn to live with.

When they're young, a lot of things will make them faint,

but as they get older, even though they'll stiffen up,

most of the time they'll find something to lean on

or they'll get their balance because they know that if they're off balance

then they'll indeed fall over.

These domesticated goats don't seem to suffer any ill effects,

but clearly this could be a problem in the wild.

Wild goats are renowned for their agility.

If they fell over whenever they were startled or a predator approached,

this genetic flaw would prove fatal.

So why did this weird phenomenon turn up in the goats of Tennessee?

There's a local legend to explain their genetic quirk.

About 1885, a man came to a little community called

Caney Springs here in Marshall County, Tennessee.

With him he brought three or four little goats.

The unique thing about these three little goats,

is that when they're startled, they fall over.

All fainting goats alive today are descended from that one small

original flock and it appears that inbreeding has led to some

genetical mis-wiring and their natural defence system

has gone awry.

Now, of course, in the wild, this behaviour would be treacherous.

It doesn't seem to be too much of a problem in a domestic herd,

but then having said that, to us, it seems very strange indeed.

From fainting goats that foxed many farmers,

we move on to sea creatures which are freaking out fishermen,

with a design flaw that's clear for all to see.

We head to the Atlantic Coast of North America, where a fisherman

landed a lobster that will have you adjusting your TV sets.

I just jumped aboard the vessel.

Just caught this blue Maine lobster.

An astonishing bright blue lobster.

A vivid contrast to its normally-coloured companion,

and if one electric blue lobster wasn't shocking enough,

another turned up, but it didn't stop there.

Ah, we got ourselves another crazy lobster down here.

Pretty funky, pretty cool.

Another was brilliant orange, the colour that lobsters go

when they're cooked, and yet this one was very much alive.

And just when they thought they'd seen it all, up from the depths came

this, an impossible looking lobster with a jaw dropping colour split.

So, what on earth can explain these colourful crustaceans?

To find out, we need to delve deeper and take a closer look

at the colouring of normal-looking lobsters.

This is what an adult lobster looks like in the wild

and they get their colour as they grow, from the food that they eat.

They feed on a diet of crustaceans, shellfish and zooplankton

and many of these organisms have a red pigment inside them

called astaxanthin.

It's the same pigment that makes salmon pink.

And it even gives flamingos their trademark colour.

So why don't lobsters turn pink if they're also eating astaxanthin?

When the red pigment is absorbed into the lobster's body,

it's laid down in its muscles and into a membrane that

lies beneath the shell.

But over a period of time, it migrates into the shell

where it's transformed by a protein into a blue pigment.

A little later, it migrates again right up to the

surface of the shell where it meets another protein which

transforms it for a second time into a yellow pigment like this.

Now, when they are all overlaid, we get to see what we see

when we look at the lobster, this dirty brown-y green colour.

This layering of colour provides good

camouflage down on the sea bed where lobsters spend most of their lives.

It keeps the young safely hidden and allows adults to stalk their prey.

Understanding the mix of colour layers in normal lobsters

means we can work out how this design can go wrong.

What happens if we remove one of those pigment layers,

say the blue one?

Well, then we're left with this, an orange-looking lobster.

But why would a lobster be missing a blue layer?

Crustacean expert Dr Grant Stentaford

knows the answer.

The orange lobsters which are abnormal, are actually missing

a very important protein, a blue protein which is

normally in the shell, and that's not produced because of a genetic defect.

So, it's a genetic design flaw that makes some lobsters bright orange.

So could the same be true for blue lobsters?

Well, people may think it's

because the lobster is missing the red or the yellow pigment

from the shell, but actually, it's more likely to be due to an

over-expression of the blue protein, or possibly the fact that the lobster

is not absorbing those red pigments from the diet that it's eating.

So the strange looking lobsters of America's East Coast

are in fact extremely rare colour mutants.

But what about that extraordinary two-tone lobster?

What's going on there?

Just before Halloween in 2012, in the waters

off of Salem, Massachusetts, this creepy crustacean was hauled in.

It's mutant orange on one half of its body,

but normal coloured on the other.

The men who caught it, Dana and Ryan Duhaime,

had never seen anything like it before.

Right away when it came on deck I said, "What is this?"

I couldn't believe we had a lobster that was orange on one side

and black on the other and straight, straight, right down the middle.

We couldn't wait to take it in to show these guys on the dock,

you know, what do you think of this?

Unlike us, each side of a lobster's body

develops completely independently.

To explain this, we have to go right back to the drawing board.

Let's look at the beginning of a lobster's life.

Once the sperm has fertilised the egg,

it grows and splits into two cells.

And this is an absolutely critical time for the lobster,

because this initial spit will define how each side of its body

develops and remains for the rest of its life.

Now very occasionally, as it makes this initial split,

there's a genetic mutation, say in the form of the genes

that code for colour.

So, if there's an abnormality on one side, as each of these cells

is replicated and the lobster grows, then that genetic

abnormality will be replicated too.

What we end up with is this,

a lobster split directly in two with a weird colour mutation on one

side and it's all down to that initial cell split.

And that explains what happened with our Halloween lobster.

But, incredibly, it's not unique.

This one from Newfoundland has an even stranger design flaw

which can also be traced back to the original cell split.

As well as turning black and blue,

it has a mutation in its sex chromosomes.

And this means that we end up with a lobster which has female sex

organs on one half of its body and male sex organs on the other half.

Almost all of the two-tone lobsters ever recorded have been

different sexes on each side.

This rare half-and-half layout is found in other species,

again where each side of the body develops independently

and where the males and the female look different.

We'll see it in butterflies and other insects.

In those cases, again, the sexes are different on both

sides of the animal, and we often see wing differences

so they can be different shapes and even different colours.

Two-tone lobsters have been surprising fishermen for a

while now, but scientists have only recently unravelled

the colourful tales that explain their appearance.

And with most lobster populations off the Atlantic Coast increasing,

we'll no doubt see more of these weird and wonderful colour mutants.

So, colourful crustacean conundrum solved.

Now to meet a true creature of legend, face to face.

On September 17, 2013, snake breeder Ross Gregersen

was checking the Mojave python eggs he was incubating.

So here's our last clutch of the year, here's the first Mojave.

-Ross made a shocking discovery.

-Here's our second one.

When I first saw him, I thought he's either dead

or he's kinked or something cos his neck's pretty goofy looking.

I poked him and he shifted and I saw this

and realised that I have a two headed Mojave.

Amazingly, both heads of this snake are alive.

And it's not a one-off.

For snake enthusiasts, two-headed animals are highly prized,

especially when the split is perfect and symmetrical like this one.

Ben Siegel owns a reptile shop

and his striking looking snake has become world famous.

This is Medusa, she's our two-headed albino Honduran milk snake.

She was born a couple of years ago and she's the mascot at our store.

I've been keeping snakes since I was six, so about 34 years,

and I've never quite seen one like her before.

We love her, she's really special to us.

She's perfect other than... she's more than perfect.

So how do snakes end up with two heads?

And what kind of double life do they have to lead?

A snake with two heads is the result of incomplete twinning.

It happens when the snake embryo is developing,

either in the egg or the womb.

The same thing can happen with human embryos

if they split into identical twins.

A glitch in the separation process means it grinds to a halt.

In this case the result is conjoined snake twins each with a head.

But as this X-ray shows, the head joins a single spine

and they share the rest of their body.

Not surprisingly, such an unusual design

sets the snake several challenges.

Gordon Burghardt at the University of Tennessee

has kept and studied two-headed snakes.

We had one animal,

that black rat snake that lived for about 20 years and we recorded

lots of its behaviour,

but in the wild, they have, I think, great difficulty.

For a start, how does a two-headed snake decide which way to go?

Well, let's look at how normal snakes move

through the world in their natural environment.

With no limbs, they propel themselves along

with a slithering motion.

Snakes can only travel quickly for short bursts,

but if a predator appears, they need to make a split second decision

to find cover.

This is a problem for a two-headed snake

because each head has an independently thinking brain,

so it's always in two minds about which way to go.

But getting around isn't their only problem.

What happens when they want to eat?

When we feed her, we take and put her in an empty, clean, open tub,

and one of our employees actually takes two food items at the same time

and tries to lure one head to one side and one head to the other side,

trying to introduce the food at exactly the same time,

so they both grab it.

Often at times, we'll actually, when one head swallows it down quickly,

we'll give it another food item so that ideally you want them to both

finish at the same time.

Then after we feed her, we have to take her

and wash her heads off with water and soap,

so that she doesn't smell like her food because then both heads

will try to attack each other just from the smell of the food

on the head.

This may sound bizarre, but smell is a critical sense for snakes.

Although some have good eyesight when it comes to

finding their prey, most snakes rely on smell more than vision.

Their tongues play a vital part in smelling.

They waft odour molecules into a structure called

the Jacobson's organ, which detects the smell.

When it comes to the smell of food,

they follow their tongues to the meal.

For a two-headed snake, a meal could be confused with

the smell of leftovers on its other half.

Evidence surely that two heads aren't always better than one.

Fortunately, Medusa is well cared for and this helps reduce

the chance of a mishap.

But in some cases, this competition for food may be more

deep-seated than we imagine,

as Gordon discovered with one of his two-headed snakes.

From all the records we had heard about,

the two heads, the animals have necks and they swallow the prey

and they go to the common stomach.

So this was what we had thought was going on,

until we did some x-rays of the animal actually feeding

and what we found is that the animal actually had two stomachs.

So their motivational systems were somewhat independent.

These were individual animals in a sense that they did co-operate

and learn to do maybe some things a little bit better together,

but, basically, they were two minds in the same body.

So, two-headed snakes are rare enough in captivity.

Just imagine seeing one in the wild.

Well, believe it or not, that's what happened fairly recently

when a group of hikers were out in the Yorkshire hills.

They spotted one of these, an adder, Britain's only venomous

species of snake, and snapped a few photos before it slithered away.

It was only when they looked at them more closely afterwards,

they recognised that the snake actually had two heads.

An amazing rarity, a UK first and experts think that the animal

is already a few months, perhaps even a year old,

so it's doing a good job of surviving in the wild.

I'm absolutely enthralled by the thought that this snake

might still be out there somewhere.

All of these stories make us stop

and think twice about what happens when nature's blueprints go wrong.

Whether it's goats overcome by the slightest excitement,

mutant lobsters equally in touch with their masculine

and feminine sides, or snakes who are in two minds about life.

These wonderful, exceptional animals remind us

that, incredibly, most of the time, nature gets it completely right.

Next, we meet animals that are pushing the limits of what

they're designed to do, deploying shocking tactics to secure a meal.

There's a fish taking a leap into the unknown,

and a bird using brain power to expand its menu.

But first, we're heading to the State of Colorado to investigate

an alarming animal crime wave.

It's the early hours of July 31st, 2013 and a shifty individual

is targeting a one-tonne waste bin at the back of this restaurant.

This isn't so much dumpster diving as dumpster driving.

The next night, he comes back and steals another dumpster.

This black bear is a repeat offender.

On another night in July, a different shady character is caught

breaking into this chocolate shop in the town of Estes Park.

This is a high calorie heist.

So, what's driving these bears to commit a summer crime wave

in Colorado?

Well, when it comes to diet,

black bears eat pretty much what we eat.

Fruit, vegetables, meat and fish,

so our food makes a good meal for them too.

This restaurant robbery took place in Colorado Springs.

It's nestled at the base of the Rocky Mountains,

an area with a huge population of black bears.

But this is the scene of the crime, a full two miles into the city.

The bear went for the bins around the back, so what lured him

so far into town?

Well, he was almost certainly led by his nose.

Bears have a sense of smell that's even more powerful than bloodhounds.

Our bear probably smelled the city leftovers from miles away.

In fact, he might have visited several

restaurants before being caught on camera at Edelweiss.

So now we know how the bear targeted the restaurant.

But how did he manage to move the heavy dumpster?

Wildlife cameraman Jeff Turner,

who's filmed bears for decades, has some ideas.

The bear's able to do what he does with that dumpster

for three basic reasons.

The first reason is the way that his feet are built.

His feet are built much like a human's or a great ape.

He can actually stand on the flat of his feet which allows him to

stand up quite comfortably in order to reach the top of the dumpster.

And then he's got very dexterous paws like his claws

and individual use of those digits and his paws allow him

to actually grip things.

The edge of that dumpster, he can get a good grip on it.

And then the third element that allows him

to move it is his strength. They're very, very strong animals,

very, very powerful, so it's nothing for him

to move something that heavy once he's in that position.

Bears have this dexterity and strength

because of the way they feed in the wild.

Perhaps, surprisingly, a lot of their calories come from insects,

which they find by moving boulders and ripping open rotting logs.

All in all, bears are actually well designed for dumpster-driving.

But where was the bear going with its haul?

Well, it turns out it was wheeling it around the corner

into a car park, to feast on the contents.

So, why go for a takeaway each night when it could have dined

al fresco at the back of the restaurant?

Bears, it seems, prefer to dine alone.

They don't like to be caught out unawares either by other

hungry bears or in this case, by humans.

All the activity and the bright lights at the back

of the restaurant are enough to put a bear off his food,

so he takes his meal-on-wheels to a quieter spot in the car park.

But why is there a spike in bear crimes in late summer,

when both of these events occur?

It's all because bears have to hibernate each winter.

Before they can do this, they must pile on the pounds

so they have enough fat to live off during the cold months.

From the end of July onwards, they all start binge eating.

That's what triggers the late summer crime wave.

It certainly provides the motive for that raid on the chocolate shop.

Last week, a young black bear broke into

Rocky Mountain Chocolate Factory in Estes Park and had a heyday stuffing

himself silly full of chocolate treats from the popular candy shop.

Seven times the bear came in, took a pile of chocolate

and went outside to eat it, getting a massive sugar hit.

And there's a theory for why the bears in Colorado,

a landlocked state,

might be more prone to pilfering than bears living near the ocean.

In this sort of an environment in the interior of the continent,

they don't necessarily have access to salmon like they would on the

coast, so their main source of food at this time of year

would be berries.

And berry crops are less nutritious than fish,

and notoriously unpredictable.

One year they might be plentiful, the next, they could be thin

on the ground, driving hungry bears into town to stock up before winter.

And just one last thing that explains why our bear is

so confidently calling for a takeout.

Just look at the way he approaches the dumpster that first night.

He already knows that this is a giant lunchbox to go.

And he's clearly enjoyed the contents of these before

and that's because he probably learned his larceny many years ago.

Bear cubs learn where to find food from their mothers.

Research suggests that the cubs of females that forage in urban

areas grow up to do the same as their mothers.

And there's increasing evidence that these bears will

head into town even when there's plenty of natural food on offer.

The result is a new, streetwise, bear-gang on the block.

Not only do they have a taste for fast food,

they've got the brawn, the brains

and the light-fingeredness to get at it all.

Our bear's midnight feast came to an abrupt end

when the owners of the Edelweiss restaurant bear-proofed their

dumpster and cut off his supply of schnitzel and black forest gateaux.

But then biologists quite often have to relocate thieving bears

into the wilderness.

Trouble is, this doesn't always work.

You see, these animals have extraordinary navigational ability.

Even the cubs can build quite complex mental maps far

better than our own. It's like they've got their own sat-nav.

So if you take them 60, 70 miles away,

within a day or two, they can be right back in town.

But the quest for food takes our next animal

into even more uncharted territory.

It's life and death on the waterways of Southern Europe.

This is Albi, a beautiful town in the South of France.

It's steeped in history, and famous for the picturesque bridges

which cross over the River Tarn.

But these waters hide a shocking secret.

When pigeons come to drink and bathe on the river bank,

they are dicing with death.

A predator is watching their every move.

And French scientists are capturing astonishing events,

never seen before.

Hundreds of miles away in the Spanish city of Zaragoza,

people are stopping in their tracks to watch the same disturbing scenes.

THEY SPEAK SPANISH

One by one, the unsuspecting birds are being plucked from the bank.

So what is preying on these pigeons and dragging them to a watery grave?

Huge fish.

But surely they're risking their own lives to leap onto land?

So what kind of freakish fish would do something so unnatural?

Closer inspection reveals a monstrous head with long

protruding feelers.

It's a colossal kind of catfish and this species

isn't meant to be here at all.

In the 1980s, fishing enthusiasts brought these catfish

from colder climes, introducing them to several parts of Southern Europe.

Since then, their numbers have grown steadily, but this is the first

time they've ever been seen lunging onto land to catch birds.

To explain why they're making such a splash in the south of France,

we need to understand how they normally find food, something

that freshwater fish expert, Jeremy Wade, knows a lot about.

People tend to think of European catfish as being fairly

sluggish creatures, snuffling around on the bottom,

eating things like worms, crustaceans and mussels.

Normally they live in quite muddy water,

that's why they've got those feelers stretched out in front of them.

They have their eyes set towards the top of their head,

they're very aware of what's going on above them.

They're very opportunistic so they'll feed on small fish

but also water birds, things like ducks that are swimming or

floating on the surface, but I've not heard of them taking pigeons before.

Catfish are voracious predators.

To catch their prey, they sneak up behind it.

At the last moment, the catfish opens its mouth creating a huge

inrush of water that literally sucks the creature in alive.

But this won't work with pigeons stood on the bank.

So how have the catfish managed to modify their technique?

The catfish are approaching very stealthily.

They're coming in very close to the water's edge and they appear to

have their feelers stretched out in front of them and what they're doing

with those is feeling vibration.

They seem to be targeting the birds that are moving,

rather than the ones that are standing still.

The prey is not going to come to the fish,

the fish has to go to the prey, which in this case involves

launching itself on land, making a lunge, a grab.

These catfish are doing something rarely seen

anywhere in the world.

They are propelling themselves into elite company,

alongside one of nature's most formidable hunters.

Killer whales off the Patagonian coast also beach themselves

to catch young sea lions.

This spectacular behaviour is a risky tactic,

but at least if they get stuck on the beach,

these mammals are able to breathe air and the reward

of a high protein meal is well worth the risk.

The European catfish are taking the same gamble by hunting pigeons

but the risks are even greater.

They can't breathe air and they could end up beached.

It's the chance of catching the pigeon that makes it all worthwhile.

But French researchers have found that not all

the catfish are making the leap onto land.

It's just a select group of medium sized fish,

ones which are about a metre long.

So why do only these fish hunt the pigeons?

You've got a very gently sloping riverbed there.

The medium sized fish are able to get within range of the pigeons

without the pigeons realising they're there.

A bigger fish tries that, actually half its head is going to be

out of the water.

Before it gets close, that pigeon's going to

realise something's up and get out of the way.

So these medium sized fish are doing it because they can.

But hunger may also be driving them to find food on land.

Maybe the bigger fish are running the river, they are the ones that

have first choice of the normal foodstuffs, but you have this

interesting situation where the medium sized fish have access

to something else that the bigger fish don't seem to be able to reach.

28% of the lunges result in a meal.

That's a good hit rate for any predator.

Fuelled by a high protein diet, these medium sized catfish look set

to join the big boys pretty quickly.

And the irony is, as soon as they grow, pigeon will be off the menu.

But all of this begs the question.

Given the benefits of this feathered food supply,

why haven't catfish done this before, in more locations?

It's to do with where they are.

An introduced species, these cold blooded killers are now

living in warmer climes for the first time.

What I think is probably a factor here is water temperature.

The water in this part of France is significantly warmer

than in their historical home range and what this is going to do

is raise their metabolic rate.

It's going to make them more active, more predatory in their behaviour,

they eat more, they grow bigger, faster.

So, there's a good chance that pigeons will be a la carte

in more places across Southern Europe as catfish numbers increase.

To take advantage of their new home, these fish have shown

remarkable ingenuity, completely changing the way they behave.

They may look primitive,

but catfish are really amazingly adaptable animals.

In the wild, they live for decades and they grow to a colossal size.

The European record was a fish caught in Italy.

It measured nearly 3m in length and weighed in at a staggering 144kg.

It's no wonder that there are stories out there

about these animals feeding on water birds the size of swans

and even swallowing dogs that were swimming in fresh water.

They truly are, if a little unexpectedly, monsters of the deep.

Big fish have crossed a line in Europe to hunt birds,

but in our next story in Israel, the tables are dramatically turned.

Not far from Tel Aviv, in a city park,

the local hooded crows have been doing something unheard of.

Like many urban birds, they'll happily take a hand-out,

but these crows aren't settling for crumbs.

Local resident Oren Hasson

enjoys watching their everyday antics in the park.

Then, one day, Oren filmed a crow taking a piece of bread.

It dropped it into the water and then...

Yes, yes, that crow just caught a live fish.

Crows have never been seen catching fish before and what's really

extraordinary, is that they appear to be using bait to lure them in.

So how have these crows learned to fish for a living?

First, we need to know more about the bird family that they belong to.

The corvids.

Many of the corvids have a reputation for their curiosity

and their problem-solving abilities, and I hope to demonstrate that now

with this raven, because underneath here I've got a test for him.

Now go on, jump down.

Immediately, he's started pulling out the string

because he knows that on the end of that is a ball

with some food in it and now he's got the reward.

Pretty smart, eh?

And remarkably, there are other cases of corvids in the wild using

ingenious techniques to find food.

These rooks have made a pit stop at a motorway service

station in the UK.

They've worked out how to get food from the very

bottom of the litter bins without risking getting inside.

They use the bin liner as a tool, pulling it up to haul the food out.

So, birds like crows can be pretty clever.

But how have the crows in Israel developed their angling abilities?

Many birds dunk dry bread into water to moisten it before they eat it.

Perhaps one accidentally ended up with a fish in its mouth.

That crow might have realised that the fish was a far better meal

and got hooked on fishing.

But then several other crows were deliberately seen using

bread as bait.

Cambridge Crow expert, Nicky Clayton,

thinks there's another intriguing possibility.

Was the bird able to figure out that bread would make a good tool

to use to lure the fish?

Did it have a plan, a series of steps in its head that it's worked out

before it's actually executed any of the behaviours?

So could these crows be thinking through a clear strategy?

What's intriguing about the video is whether the hooded crows

are actually capable of delayed gratification.

That is do they understand that by using a piece of bread

as a tool to lure the fish, they can actually get a much better reward

later, the fish, rather than just eating the piece of bread right now.

Delayed gratification for an animal like this crow is no mean

achievement, particularly as it's not something that comes easily

to humans.

Child psychologists have known for a long time that

if you offer children under five one marshmallow now,

or two marshmallows later and then you leave one on a plate for 15

minutes, by the end of that period it's almost invariably gone.

And who can blame them!

When crows resist temptation like this,

they also reveal another remarkable ability.

They've got an awareness of time, and that's something,

planning ahead, remembering the past that was thought

until quite recently to be unique to human beings.

So, crows can make and learn to use tools to help them find food.

And they're capable of forward planning and delayed gratification.

So how is all of this possible for a bird brain?

It turns out that crows are a cut above most of their feathered

friends when it comes to the old grey matter.

When we look at the structure of crow brains,

they have areas which are enlarged compared to other birds

and these same areas are the ones that in our brains relate to

memory, planning ahead and delayed gratification.

These amazing new discoveries are leading scientists to make

striking comparisons between crows and great apes.

Relative to their body size,

crows and chimpanzees have equivalent sized brains.

They both use tools and scientific tests are starting to show

that by some criteria, crows are as intelligent as chimpanzees.

Somehow, these very different animals have both developed similar

kinds of brainpower.

It's a mind-blowing thought.

Who'd have guessed that feeding bread to birds in the park

could lead to such startling revelations?

These stories show the extraordinary mental

and physical lengths that animals will go to get a meal.

Whether it's a bear pushing the boundaries,

an astonishing fish out of water,

or a bird brained genius.

These animal innovators have stretched the very

limits of what their brains and bodies are designed to do.

Next, to the design of some of nature's weirdest defences,

improbable strategies for personal protection or

the survival of a whole species.

From birds acting like lame ducks, to shrinking reptiles.

But we start in the USA with a defence strategy that appears

to have backfired terminally.

From time to time, Americans stumble upon apparently dead bodies.

-Uncle, pick it up!

-I ain't touching that thing.

-Must be poisoned.

-I don't want to touch stuff like that.

-Is it going to bite?

Finding what looks like the corpse of a baby rat can be

an unsettling experience.

Watching one lose the will to live in front of your eyes

is even weirder.

Has it died of fright?

Well, no, because these are North American mammals called

Virginia possums, often known as possums for short.

See this thing? It looks dead, doesn't he?

But he isn't. He's just playing possum.

So what is this possum playing at?

The American expression "playing possum" refers to someone

pretending to be dead, and it was inspired by this behaviour.

This bizarre phenomenon is known as thanatosis.

The possum goes stiff, then opens its mouth

and drools with its tongue hanging out.

Its eyes stay open but its breathing becomes slow and shallow.

Despite appearances, its heart continues to beat at a normal rate.

The possum isn't really shutting down, it's just faking it.

At first glance, this is a fatally flawed defence strategy.

-The possum is in mortal danger.

-Oh, my gosh!

-So why doesn't it run away?

Well, needless to say, possums are not as daft as they look.

Their natural predators include horned owls, coyotes,

bobcats, foxes and racoons.

But with a top speed of about 7mph, running isn't an option,

so the possum doesn't stand a chance against most of these animals.

Yet pretending to be dead when confronted with something

that wants to eat you still seems like a strange response.

But seeing a coyote hunt a possum suggests how faking death

might be the best way of avoiding real death.

The coyote thinks the possum is dead already

so it doesn't bother to kill it.

It switches from full-on attack mode to a more gentle,

meal-handling behaviour.

But the possum is still on the menu so surely real death is inevitable.

Predators don't always get stuck into a meal straight away.

Some species, like owls and foxes, actually hide food for later.

Anyone keeping chickens will know about this scenario.

The fox takes one carcass away from the coup

and hides it in a food cache, returning for another body.

Substitute a death-feigning possum for a chicken

and it would find itself being abducted to the cache site

and then left.

Left for dead, at which point the possum would make its escape.

The case of the coyote reveals the second reason that

playing dead works.

Predators often kill opportunistically

and if they aren't actually ravenous,

they might lose interest in the prey when it appears lifeless.

That means the possum still has a chance.

Whilst the coyote's back is turned, it can slip away,

slightly worse for the experience, but at least it's alive.

So, faking your own death is a risky but effective strategy.

But possums aren't the only animals to evolve what might

seem like counter-intuitive anti-predator strategies.

It happens here in the UK too. These are little ringed plovers.

They lay their eggs on a patch of shingle.

The eggs are speckled for camouflage, but on the ground,

they're still vulnerable to predators like foxes and jackdaws.

This jackdaw knows the eggs are there somewhere,

but the parent birds have left the nest and are flapping

about right under the jackdaw's nose, but this is all a ruse.

Look at the bird in the foreground,

pretending to have a broken wing, trying to look injured

and vulnerable and show that they would be an easy meal.

This is a distraction designed to draw the predator

away from their eggs.

In this case it didn't work. But the strategy is often successful.

As soon as the threat has passed, they drop the act

and return to business as usual.

Birds are likely to perform these distraction displays

at the most critical point in their breeding cycle,

notably when the eggs are just about to hatch.

If they fail there, then they've wasted an entire breeding season.

Oh, and one last note on these bizarre displays.

On land, it's likely that you'll see birds performing them.

Because they're very agile, they can fly away if there's any trouble.

Less mobile animals, well, if they practise this sort of deceit

and get it wrong, it could be fatal.

Some of nature's best defences involve going unnoticed.

We're off to Madagascar to discover the ultimate in downsizing.

A huge island off the coast of Africa, Madagascar is a strange

looking land, and home to an impressive array of animal oddities.

Some of the weirdest are the chameleons.

Here, there are more species of these larger than life

lizards than anywhere else on earth.

These eye-catching characters are shaped in the classic

chameleon design.

They're big, bold and famous for their telescoping tongues.

And, of course, for their legendary ability to change colour.

They use this to communicate with each other

and to blend into the background to avoid predators.

But in 2012, scientists were exploring the furthest

fringes of Madagascar when they discovered this.

A tiny chameleon, and the world's smallest reptile.

It was so astonishing that it made headline news.

It measures just 29mm, and this is a fully grown adult.

This strange new species, named Brookesia micra,

is a fraction of the size of its flashy cousins.

So why would a lizard adopt this extreme miniaturised design?

Frank Glaw, of the Zoological State Collection in Munich,

made this diminutive discovery and he was instantly intrigued.

It's always a great exciting feeling if you discover new species,

especially if you can immediately recognise it as new.

In this case, it was so small, it was immediately clear

that it is different from all the other dwarf Brookesias

and so it was very exciting to have this small animal in our hands.

Brookesia micra belongs to a family of highly specialised

dwarf chameleons.

These little lizards have found a niche down in the leaf

litter of Madagascar's forests.

Scientists think there may be less predators here, and certainly

their dull brown colouring means they're very well camouflaged.

There are more of these dwarf chameleon species in Madagascar

than anywhere else in the world.

But why is Madagascar such a hot spot for these

incredibly tiny chameleons?

What is it about this place that might favour a tiny design?

Well, it's possible that island life tends to promote the little guy,

something known as insular dwarfism.

It suggests that when a normal sized species is

trapped on an island or on an isolated patch of land,

over time, it actually evolves into a smaller creature.

This shrinking process might happen if food was in short supply.

Only the smaller individuals will survive,

because they can get by on less.

When they reproduce, they'll have smaller offspring,

and so on and so on.

Down-sizing, then, can be a long term survival plan.

OK, so that might explain how the other dwarf

chameleons on Madagascar's mainland came about,

but Brookesia micra was found on a little island

off of Madagascar's north coast.

Here, resources are even more limited.

We have the large island of Madagascar that favoured

evolution of tiny Brookesias, and then

we have tiny offshore islands and so we could expect that natural

selection will favour even more tiny chameleons than on the mainland.

So, Brookesia micra's diminutive design may be

the result of a double dose of down-sizing.

This remarkable little animal has yet to reveal all of its secrets,

and, incredibly, scientists think there's a chance that these

chameleons may get even smaller in the future.

Shrinking yourself as a defence strategy is certainly pretty weird,

but then again it's working for the miniature chameleons of Madagascar.

The question is though, just how much smaller could they get?

Well, it appears that there might be a limit to miniaturisation

governed by the complexity of one organ.

It's not the heart, it's not the lungs, it's not the liver,

it is in fact, the eye.

As these stories show us, many of nature's defence plans

are stranger than we could possibly imagine.

Whether it's a possum faking its own death,

birds deploying distraction techniques

or lizards shrinking into the background,

they're all strange and curious designs

showing nature at its weirdest.

So there you have it.

We have witnessed some shocking events,

uncovered some fascinating new science

and also seen the weird and the wonderful.

And with its bizarre animal behaviour

and strange natural phenomena,

there's no doubt at all that the natural world still has

the power to leave us both baffled and amazed.

And with so much more to discover,

it also leaves us with one last question.

What on earth next?