Elephants The Wonder of Animals

Planet Earth.

Millions of different species.

But a few are special.

Thriving.

Dominating.

The key to their success lies in their opportunism.

For others, it's down to their ability to collaborate.

And for some, it's all about surviving where others can't.

So, what is their secret?

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.

The African elephant.

The largest land animal on the planet.

Colossal, lumbering and ponderous.

Their astonishing body has always fascinated us.

Their sheer size seems ill-suited to surviving

in some of the most challenging habitats on Earth.

But the inner workings of these giants

is highly sophisticated and intricate.

Allowing them to defy the extreme heat of the desert.

To find food and water in a sparse and barren landscape.

And to repel predators, both animal...

..and human.

In this episode, we are going to explore each element

of the elephant's remarkable body.

We're going to unlock the secrets

of how its extraordinary anatomy and surprising physiology

have enabled it to become one of the greatest survivors

in the natural world.

The Namib Desert, southern Africa.

Temperatures here can exceed 45 degrees Centigrade.

There's very little shelter.

So the first survival challenge facing the elephant here

is to avoid overheating.

And various parts of their anatomy help out.

The African elephant has the largest ears of any animal,

accounting for 20% of their overall surface area.

Although they make useful fans,

they also help cool the elephant down in another, more subtle way.

These thin flaps dissipate heat fast

and are therefore cooler than other parts of the body.

The hotter, red areas are blood vessels

which can be expanded when required,

allowing more blood to flow through them.

When needed, they can pump up to 12 litres every minute.

Working in a similar way to a car radiator,

as the blood passes through, it's cooled by the air,

helping the elephant to lose heat quickly.

But a recent scientific study has discovered

that it's not just in the ears that this technique is used.

Researchers at the University of Veterinary Medicine in Vienna

noticed that as elephants warm up,

certain parts of their body appear hotter than others.

The study found that these hotspots

have a particularly high concentration of blood vessels

located just beneath the surface of the skin.

By allowing more blood flow through these areas,

the elephant is able to fine-tune its cooling process,

helping to maintain a perfect temperature.

And the skin itself is special, too.

Unlike most mammals, elephants don't sweat.

They simply can't afford the loss of water in this parched wilderness.

Instead, their skin has evolved a very different way

to help them battle the heat.

Every inch of an elephant's body is covered with wrinkles.

These help keep an elephant cool by trapping mud and dust.

This then acts as a sunscreen.

And it's been calculated that wrinkly skin

can hold 10 times more muddy water than smooth skin.

But there's one more cooling element their skin has to offer,

and it may not seem obvious.

The elephant is covered in long, wiry hairs.

In all other mammals, hair is used to provide insulation.

But in 2012, research from Princeton University

revealed that they actually help cool the elephant down.

They act as conductors, drawing heat away from the body.

This is the first time that any mammal's hairs

have been found to help lose, rather than retain body heat.

Elephants have been able to withstand the extreme heat,

and it's all down to their surprising body.

But they still need food and a regular supply of water.

And here in Africa, these are often in short supply.

Elephants need to drink every two to three days.

So finding water is a relentless task.

At the height of the dry season,

the plains are parched and water is scarce.

But elephants can locate rain even when it's hundreds of miles away.

THUNDERCLAP

By using their feet.

Research suggests they can pick up a storm's infrasound.

The low frequencies undetectable to the human ear.

THUNDERCLAP

One theory is that the highly-sensitive soles of their feet

can detect minute seismic vibrations.

To determine the locality of a faraway storm.

This incredibly subtle adaptation

may explain how, even on a clear day,

elephants seem to know exactly where to go to find rain.

THUNDERCLAP

Many different herds will travel vast distances

to get to the same supply of fresh water.

TRUMPETING

And this is much more than just a chance to rehydrate.

It's also an important occasion for socialising and playing.

Here, the young must learn from the adults

how to use their trunks to drink.

And how to clean themselves.

At an abundant water source like this,

elephants can consume up to 220 litres in a single day.

But how do they cope when they're nowhere near water?

After just three days without drinking...

..elephants begin to succumb to dehydration.

But to survive for an extra few hours, they've evolved a neat trick.

At the back of their tongue,

they have a reservoir called the pharyngeal pouch...

which can store up to five litres of water.

As a last resort, they can access this emergency supply

by putting their trunk down their throat and into the pouch.

They can then drink it, or spray it over themselves

to cool down the blood vessels in their ears.

And this anatomical adaptation is unique to elephants.

It could mean the difference between life and death.

In the arid regions of Africa,

there's not only a shortage of water.

For herbivores, there's also a lack of high-quality food.

Tree bark...

..branches...

..and grass...

are all difficult to digest

and can have little nutritional reward.

In fact, relative to its size,

the elephant diet contains fewer calories

and less protein than that of any other mammal.

So they need to consume vast amounts just to stay alive.

Grazing up to 19 hours

and eating up to 300 kilograms every day.

None of which would be possible without their trunk.

A fusion of their nose and upper lip.

It's immensely powerful.

Capable of lifting up to 350 kilograms.

But it's flexible, too.

Allowing them to reach seven metres high up into the trees.

And it's also highly sensitive.

On the tip of an African elephant's trunk

are two finger-like extensions

that can be pinched together to grasp even the tiniest morsel.

And inside, it's even more intricate.

The elephant's trunk contains more than 100,000 muscle units.

Fluid within the muscle cells becomes firm when compressed,

working like a hydraulic system,

offering superb flexibility and rigidity.

Different sections of the trunk can work independently

and can bend or twist, lengthen and shorten.

It's one of THE most versatile tools in the animal kingdom.

And when combined with their tusks,

the elephant is formidable.

Elephants' tusks occur in both males and females

and they're actually modified teeth.

Incisors that develop in the upper jaw

and replace milk teeth around six months after birth.

They can keep growing as much as 17 centimetres a year

and can reach three metres in length.

And because elephants favour one tusk over another,

they tend to be worn down at different rates.

Working in tandem with their trunk,

an elephant's tusks are an invaluable tool for moving trees,

stripping branches and foraging for food.

And once they've harnessed that food,

it's the teeth inside their mouth that take over.

Elephants have four huge molars.

The largest of any mammal alive today.

Each one grows up to 30 centimetres high

and can weigh as much as five kilograms.

Their size and shape is crucial

when it comes to eating such a tough diet.

But these teeth are not permanent.

If they were, once worn down, the elephant would starve to death.

Instead, they've evolved an ingenious solution.

Unlike most mammals,

elephants' teeth grow in cycles throughout their lives.

The molars start at the back of their mouth

and gradually move forward,

pushing out the older ones which are worn down.

It's like a conveyer belt.

And these teeth can be replaced up to six times

during the elephant's life.

But vegetation alone can't supply all of the elephant's needs.

And their quest for a balanced diet leads them to some unusual places.

This cave in Kenya is deep inside an extinct volcano.

The walls are covered with thousands of scratch marks.

Some are 150 metres down in the darkness.

In the middle of the night, elephant families visit the cave.

They come here to mine the salt from the cave walls.

All mammals need salt.

But there simply isn't enough sodium in the elephant's herbivorous diet

to sustain such a huge animal.

So elephants are constantly on the hunt for it.

They use their tusks to scour the walls.

Scratching away the salt...

..to supplement their diet.

They've been coming here for generations.

Able to return to the same location year on year,

thanks to an astonishing long-term memory.

Elephants have the biggest brain of any land mammal.

But there are two parts of it that are particularly enlarged.

The cerebral cortex...

..and the olfactory system.

These areas are fundamental

to complex learning and, crucially, memory.

Allowing elephants to store and process information

that's vital to their survival.

And this capacity to learn and remember

has helped them to survive

some of the worst that nature can throw at them.

One study found that in a severe drought,

the older females led the herd to a waterhole

hundreds of miles from their home territory.

They can even recall the exact location of water sources

last visited over 30 years before.

Elephants have an incredible long-term memory.

This doesn't only help them find food and water,

it also helps them avoid predators.

Although huge, elephants are hunted by lions.

The big cats target younger elephants

if they become separated from their herd.

TRUMPETING

SNARLING

So when the two are forced to share a waterhole,

elephants must know exactly how to protect their young.

TRUMPETING

And for this, they rely on

the memories of the older members of the herd.

A recent study suggests that the older matriarchs

with a greater accumulated knowledge

make better decisions than younger ones

when they're faced with a predatory threat from lions.

So herds with older individuals are less susceptible to attack.

They keep the young at the centre of the group,

forming a defensive cordon to hold the lions at bay.

Each encounter reinforces their memory

and helps keep the herd safe for generations to come.

But perhaps the elephant's greatest feat of memory

is in defence of the biggest of all threats to their survival.

Humans have been killing elephants for thousands of years.

But it's not just for their tusks.

The Maasai tribe in Kenya are cattle herders.

And as a result, frequently come into conflict

with elephants over precious resources.

These animals are often killed as a result.

But they use their memory

to protect themselves in a remarkable way.

A brand-new scientific study

has discovered that elephants can recognise

and remember the dialects of those tribes

that have threatened them in the past.

The researchers played audio recordings

of two different local tribes to a group of elephants.

Firstly, the Kamba people,

who rarely come into contact with elephants.

KAMBA DIALECT

The herd appear relaxed throughout.

But this is what happened when the same herd

were played a recording from the Maasai tribe.

MAASAI DIALECT

TRUMPETING

What's more, the research found that it's not just separate tribes

that elephants can differentiate between.

They appear to be able to distinguish

between gender and even age.

Correctly sensing the threat of older male Maasai,

but not reacting to recordings of the unthreatening women

and young adults from the same tribe.

It's the elephant's capacity to learn and remember

that has increased their chances of survival

in an ongoing battle for scant resources.

Within their huge frame, the most surprising adaptations

enable elephants to stay cool in extreme heat.

To find food and water in barren landscapes.

TRUMPETING

And to learn how to avoid their single greatest threat, humans.

This has allowed them to become

one of the great survivors of the natural world.

And that is The Wonder of Elephants.