Penguins The Wonder of Animals

Planet Earth.

Millions of different species.

But a few are special.

Thriving.

Dominating.

These are the opportunists...

..the collaborators...

..the survivors.

What makes these animals so successful?

By delving deep beneath the skin,

we'll reveal the unique features that set some species apart.

In this series, new behaviour

and the very latest scientific research

will throw fresh insight into the wonder of animals.

At first sight,

penguins seem ill-suited to their environment.

But this humble bird

has actually conquered an extraordinary range of habitats.

From deep forests...

..to tropical waters.

Bustling cities...

..to busy beaches.

And most impressive of all, the toughest place on the planet.

Antarctica.

Where they not only survive,

they thrive.

So exactly what is the secret to their success?

Now penguins have a unique body shape.

A rotund abdomen, stubby little legs

and stiff wings may not seem like the perfect recipe

but I've got to tell you that sometimes

appearances can be deceptive.

These very characteristics

are central to the penguin's success,

starting with those legs.

These are Chinstraps.

Residents of Deception Island

in Antarctica.

After spending the day 60km out at sea hunting krill,

they now need to get the much-needed food back to their chicks.

Like all penguins, they spend a lot of time at sea

but surprisingly half of their time is spent on land.

So their bodies have to operate effectively in both environments.

Their short legs, positioned right at the end of their bodies,

seem to work against them,

forcing them to waddle.

For every penguin species,

this bizarre rocking motion is the only way they can walk,

but it actually works in their favour.

Like a pendulum, the motion stores energy at the end of each swing,

energy that can be spent in the next step.

The percentage of energy retained is known as the recovery rate.

Humans have a recovery rate of about 65%,

in penguins however, this can be up to 80%.

But for our Chinstraps, walking is only half the challenge.

Their nesting site is 160 metres high above them,

on the rim of a volcano.

It's a near-vertical climb.

Compounded by wet and slippery volcanic ash.

The Chinstraps' feet may be short, but they're also very strong

and they're armed with sharp claws.

Their anatomy wins over.

Against the odds, penguins' legs work well on land.

But it's beneath the waves where they really come into their own.

They can swim faster and deeper than any other bird...

..accelerating to 15mph in less than a second...

..and reaching depths of up to 500 metres.

The position of their legs is vital.

Most other swimming birds

use their legs to propel them through the water.

But, sticking out of the middle of their bodies

these legs cause unwanted drag.

Penguins, on the other hand, are different.

Their feet and legs are tucked away at the very end of their bodies

minimising drag significantly.

In this position, they act as an effective rudder system.

Controlling both lateral and vertical motion.

This enables these birds to make a perfect 180 degree turn

in as little as a fifth of a second.

So penguins' legs can allow them to climb volcanoes

and manoeuvre through water with ease.

But where does their power come from?

Well, it's all in the wings.

For most birds,

wings are highly specialised pieces of apparatus

that have evolved to allow them to fly.

And if we look at this pheasant skeleton

you can see that the main joints in the wing,

here at the shoulder, the elbow and the wrist

are shaped to allow it to flex, to flap

so the bird can eventually get into the air.

Penguins, on the other hand, lost the ability to fly

some 60 million years ago

and two of the joints in their wing,

here at the elbow and the wrist have fused.

In fact, these days the wing can only move at the shoulder

and it's this that gives penguins their characteristic posture.

And although a hindrance on land,

they are fundamental for underwater propulsion.

The fused joints and rigid flattened bones

create the perfect paddle.

Faultlessly adapted for "flying"

through the water.

A penguin's wings and legs may appear cumbersome,

but, when combined with a torpedo-shaped body,

adapted to glide through water,

these birds make the most exquisite swimmers.

It's a body plan that has enabled around 17 species to thrive,

right across the southern hemisphere.

They occur wherever nutrient-rich cold waters are found,

but can also be seen as far north as the equator

6,000 miles from the South Pole.

The seas here in the Galapagos

are refrigerated by currents flowing all the way from Antarctica.

The warmer waters of the equator create a thermal barrier...

..preventing the penguins from conquering the northern hemisphere.

In those tropical conditions,

their rounded, blubber-filled bodies

would simply overheat.

But it's exactly this body shape

that allows penguins to survive year round

in a place that no other animal can.

Antarctica.

Dark,

barren

and locked in ice for much of the year.

This is a desert like no other.

It's the coldest,

windiest,

driest continent on earth.

It's hardly rained or even snowed for two million years.

And yet, against the odds,

six penguin species call this place home.

And they all follow a similar, rounded body shape.

Consisting of up to 30% blubber.

But there's more to a penguin's cold-conquering anatomy

than just fat.

Beneath this rotund exterior, lies a complex system of mechanics.

In the chill of Antarctica, the extremities are most at risk.

Feet and wings are inevitably going to get cold,

but it's vital for the penguin's survival

that they can operate at any temperature.

To work effectively, muscles require heat.

So, instead of housing them in their exposed limbs

a penguin hides these muscles deep inside its insulated body.

Here, these warm muscles connect to tendons,

which are much less susceptible to cold.

And it's these tendons that then connect to the bones

within the feet and wings.

Working like a remote operation by wire,

the penguin has complete control over their essential limbs

even in the coldest conditions on the planet.

But to keep this muscular powerhouse warm,

their bodies need some serious insulation.

Penguins may not be able to fly,

but they have more feathers than any other bird.

In fact up to three times the amount, densely packed together.

The small, stiff feathers overlap so tightly,

they form a protective seal,

trapping a blanket of still air

between the skin and a fluffy feather outgrowth.

It's a highly sophisticated form of insulation.

And yet, these same feathers have a very different purpose too.

Here in South Africa, extreme cold is no longer an issue.

For African penguins, their feathers hold the key to cooling off

as well as warming up.

The secret is a muscle attached to the base of each and every feather...

..which opens up the densely packed layers

allowing heat to escape from the swollen blood vessels.

Penguin feathers offer complete climate control

in both hot and cold weather.

And it's so effective, they can even trick state-of-the-art technology.

When scientists from Glasgow University

recently studied Emperor penguins using a thermal imaging camera,

something didn't quite add up.

As warm-blooded animals in a freezing environment,

they expected the birds to register hotter than their surroundings.

But they actually clocked in at five degrees cooler.

The very outer feather layers

are losing a lot of heat to the clear sky above them,

which makes the penguin's exterior edge appear colder

than the surrounding air.

You would expect this to be a problem

but as we've seen, penguin plumage is special.

In fact, the interlocking, densely packed feathers

create such a strong barrier,

that although the temperature of the outer layer

was measured at minus 23 degrees centigrade,

the penguin's actual body temperature was up to 60 degrees hotter.

Despite a thick layer of blubber,

more than 80% of a penguin's insulation

is down to their incredible feathers.

And they need it.

When the polar winter draws in,

it gets darker

and much, much colder.

With the wind chill, temperatures can drop

to an astonishing minus 70 degrees centigrade.

But the Emperor penguin is the ultimate specialist

in extreme survival.

Its anatomy allows it to face an astonishing challenge.

It doesn't just survive the winter,

it's the only animal to breed here in the winter.

Enduring these conditions makes sense,

it means their chicks will fledge at the right time in spring

when the seas are at their richest.

To achieve this, the males must spend up to 120 days without food,

each incubating a single egg in the middle of the Antarctic winter.

Meanwhile the females are nearly 100km away,

fishing on the edge of the ice sheet.

For the males left behind,

feathers, blubber and hidden muscles simply aren't enough.

It's long been known that the males shuffle into "huddles"

with their eggs safely stored on top of their feet.

Sometimes these groups reach into the thousands.

Strength in numbers against the bitter cold.

It is effective.

Temperatures can vary dramatically

depending on a penguin's location in the huddle.

Scientists have measured as high as 37 degrees centigrade

in the heart of the group,

which is up to 80 degrees hotter than on the outer edge.

It had been thought

that the penguins kept warm with all of this huddling tightly together.

A recent discovery, however, has turned that theory on its head.

Instead of squashing into one another's plumage,

these penguins are barely touching.

This prevents the feathers from being compressed,

which would compromise their powers of insulation.

So keen are they to protect this treasured outer layer,

that an individual penguin only needs to move two centimetres

for its neighbour to react,

also performing a two centimetre step in the same direction.

Just one penguin's movement

creates a chain reaction throughout the huddle.

Like a Mexican wave.

Prior to this study,

it was believed that these waves were caused by cold penguins

pushing in to the warmer centre,

but now we know they can originate from any bird

in any position within the huddle.

It could even be started by a warm bird in the centre

travelling outwards to cool down.

As the sun returns, so do the females.

Allowing the males to head out to sea.

Now they can feed and build up enough fat reserves

for another gruelling breeding season.

It's here that another fantastic feathery adaptation comes into play.

The Emperor is the largest species of penguin.

Weighing in at up to 38kg,

a third of which is blubber.

The more body fat,

the more likely they are to survive the coming winter.

But to maintain it,

they need to hunt.

Diving longer and deeper than any other penguin.

They hold their breath for up to 20 minutes at a time

to maximise their chance of finding food

and building up their vital fat stores.

But all that bulk comes at a price and poses an interesting problem.

How does a bird the same weight as a baby hippo

get itself back out of the water?

A recent, revelatory study suggests an intriguing solution.

A team of European scientists

recently looked again in more detail

at some long-observed penguin behaviour.

At the end of a long dive,

instead of jumping straight out of the water,

many Emperors surface for a short time and then dive back down again.

Only then do they shoot back up to the surface,

this time accelerating clear of the water.

So why do they have this temporary pit stop?

The obvious answer is that they return for a much needed gulp of air

and a bit of rest...

..before diving back down to pick up enough speed for their grand exit.

But what the research team now think is going on,

is actually a lot more interesting.

When the birds come to the surface, they appear to preen.

In fact they're actively collecting air

within a fine, downy mesh at the base of their feathers.

As the penguins descend, the water pressure increases,

reducing the volume of the trapped air by up to 75%.

The birds again rely on their individual muscles

at the base of each feather.

This time, they clamp them shut,

locking in the compacted air that they've collected.

When it's time to exit, the penguin then swims upwards,

as fast as it can.

The trapped air in the plumage

expands during their ascent and pours through the feathers

producing the bubbly wakes we can see behind them.

The tiny micro bubbles form a lubricating coat of air

that surrounds the penguin.

This drastically reduces drag

and allows them to accelerate to twice their normal swimming speed

at the point they leave the water.

This flightless bird...

..finally becomes airborne.

Penguins possess a truly extraordinary anatomy,

perfectly adapted to thrive in some extreme environments.

Their feet reduce drag underwater

and even allow them to climb volcanoes.

Their wings are perfect for flying beneath the waves.

And their rotund body

is packed full of hidden mechanics and covered with feathers

which keep them cool and warm.

And even allow them to propel themselves out of the water.

Thanks to their unique body plan,

they're not just one of the great survivors

they are one of the most successful animals on earth.

And that is the wonder of penguins.