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You have started a journey
into the heart of the animal world,

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where many of nature´s supernatural powers

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are waiting to be revealed.

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These sensory and physical
powers seem out of this world.

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Many can be explained
by the latest scientific discoveries.

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The powers of animals are as extraordinary

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as any human mysteries,
such as the Bermuda Triangle.

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Although science has solved
many of nature´s mysteries,

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they still deserve the accolade supernatural.

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0ur series of dramatic journeys

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will investigate different kinds
of animal powers.

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0n this journey
we explore animal perception

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and show creatures
with senses beyond our own.

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(Rapid bleeping)

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We confront the limitations
of our senses

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when we´re plunged into another world.

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Here, the senses of others
are far superior.

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Compared to us, sharks have
extrasensory perception.

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Extra senses, as well as senses
more enhanced than our own.

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They can smell blood
from over a kilometre away.

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And hear struggling sounds
pitched below our hearing limits.

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They even detect forces
beyond any human sense.

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Electrosensors surround its mouth.

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These detect the electricity of life itself.

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Body electricity creates a living aura.

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Body openings leak more electricity.

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A cut bleeds electricity
three metres into the water.

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Electrical discharges from metal
in salt water provoke an attack.

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Sharks are so sensitive,

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they mistake the tiniest
electrical signal for life.

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A five billionth of a volt
is enough to merit investigation.

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Even unplugged,

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enough current flows between
different metals to be perceived.

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Sharks are not alone
in sensing the spark of life.

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The stingray is tuned
to the body auras of other rays.

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The male uses this power
to find females hidden in the sand.

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His electric sense is so sophisticated,

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he can recognise her distinctive aura.

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He feels the electricity
flow between them.

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With eyes on the top of his head,
he can´t actually see her.

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They are the most electrosensitive
of all animals.

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Such attraction may climax
in an orgy of electrical stimulation.

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The torpedo ray has found
a stunning use for its electric aura.

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Using modified muscles like a battery,

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it boosts its body electricity
to lethal levels.

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It delivers a shocking
two-kilowatt bolt,

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equivalent to dropping
an electric fire into a bath.

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Like all living things,

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our electric auras
only survive as long as we do.

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There are many kinds of extra senses.

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Some are enhanced versions
of our own senses.

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The vision of birds far surpasses ours.

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Like us, they see full colour.

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But many perceive an eerie extra hue.

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( # 0pera )

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This light is so damaging to us,
we protect our eyes from its rays.

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To prevent this ultraviolet light
harming our skin,

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we anoint ourselves with sun block.

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0ur appearance must seem bizarre.

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The lotion absorbs UV,
giving us a strange complexion.

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0ur hair and fingernails reflect UV,

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making them glow.

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To courting king parrots,
appearances are everything.

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The female eyes up
the male´s ultraviolet plumage

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before she makes her choice.

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Like us, she tends to be choosy.

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UV vision also helps birds find a meal.

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Most fruit has a waxy coating
that reflects ultraviolet.

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(Squawking)

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Like a neon sign,
it shines out to birds in the wild.

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Fast food has tempted parrots
to take up city life.

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0thers have followed the parrots in.

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The grey goshawk.

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(Dog barking)

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Like sun lotion, urine absorbs UV,

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making stains highly visible to birds.

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Small mammals
mark their runs with urine,

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leaving evidence of their movements.

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This can guide predators
to the best hunting grounds.

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For parrots, ultraviolet
may even act as a last defence.

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UV flashes create confusion
for the hunter.

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(Squawking)

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The power of this light fantastic
seems almost unlimited.

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It may help a lost bird find its way
out of the urban jungle.

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(Horn blares )

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Birds are now thought to see
the patterns of polarisation

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that radiate from the sun.

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These are more noticeable in UV
than any other wavelength of light.

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Like a map in the sky,
they signpost the sun´s position

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and may help guide the birds home.

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( # 0pera )

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This kind of map reading
was first discovered in insects.

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(Buzzing)

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Bees, like us, have full colour vision,

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but their range is shifted away
from red towards ultraviolet.

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Their compound eye
limits the detail they actually see.

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In Arizona, even the cotton plants
have extra senses.

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They use them to talk to insects.

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When attacked by caterpillars,

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the leaves send out a chemical S0S.

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Carried on the wind, it´s the signal
this wasp has been waiting for.

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Soon, others receive
the plant´s rallying call.

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A whole squadron of wasps
is summoned by the plant

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and the caterpillars are doomed.

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These wasps are parasites.

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They inject their eggs
with a well-aimed stab.

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Each lethal injection
will spawn an alien invasion

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that consumes the caterpillar
and saves the plant.

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The plant´s chemical scents
also attract pollinators.

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These humble insects
use chemical extra senses

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in a remarkable way.

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Returning bees carry
a chemical identity pass

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and are security checked
by guard bees,

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the defenders of the colony.

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Increasing vibrations
provoke the guards

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to release a warning from their sting.

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This chemical message alerts
the hive to the growing threat.

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The guard investigates.

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Vibrations and synthetic smells
all provoke attack.

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And these bees are hyper-reactive.

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They´re the descendants
of a Brazilian experiment

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that crossed honey bees
with African strains.

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The killer bee has now invaded
southern USA.

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The poisonous sting
pumps out a pheromone.

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This goads the swarm
into a stinging frenzy.

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With their extra senses enhanced
by human breeding,

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they´re a killing machine.

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Running is only for the fit.

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Killer bees can give chase up to a mile.

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Even here, there´s no escape.

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The bees may wait for over an hour,

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perseverance derived
from their African ancestors.

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Killer bees were the result
of a disastrous human experiment,

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but killer plants exist in nature.

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They even talk to each other.

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Acacias can warn their neighbours
of impending danger.

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When eaten by a browsing animal,
the leaves release a gas

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that conveys a message
to nearby trees.

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When the leaves receive the signal,
they react in a remarkable way.

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Toxins spread throughout the leaves.

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In just 30 minutes, the leaves
are laced with poisonous tannins.

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To avoid poisoning,
giraffes and antelope

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only graze for short periods
before they move on.

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Many of the secret powers
of plants have just been revealed.

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The more we discover,
the more like animals they seem.

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Distort our perception of time
and the similarities become clearer.

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Even though they lack
specialised nerve cells,

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they do have a primitive nervous system

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that transmits electrical signals.

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Cut the grass and it reacts, nervously.

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Electricity fires a warning bolt.

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This electrical impulse
tells the grass to grow

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and become more toxic.

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It responds as though we were
a grazing animal and fights back.

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Climbers, like these passion vines,

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have tendrils sensitive
to the slightest touch.

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The electric message
passes through the plant cells.

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The tendrils react by growing
a spring-coiled clasp.

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If plants are so sensitive,

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how do household plants react
to our attentions?

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Deprived of outside stimulation,

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a caring touch
actually promotes growth.

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Even tiny voice vibrations
may excite a house plant

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and trigger stretch-sensitive cells
responsible for growth.

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Best of all, the carbon dioxide
from our breath is food.

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For plants, it´s good to talk.

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Plants are so sensitive, some even
sense the coming of storms.

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(Thunderclap)

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A bird´s extra senses include hearing.

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They detect thunder at a pitch
far below our hearing limits.

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These infrasounds
carry hundreds of kilometres

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and may warn of bad weather ahead.

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Hearing infrasound may give birds
another surprising power.

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To migrate successfully,
pelicans must find

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the twisting columns of hot air
known as thermals.

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These create
a storm of infrasound.

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They also hear the infrasound
from office air conditioning, cars,

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and even underground gas mains.

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Although inaudible to us,
these sounds can make us feel ill.

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(Siren wails)

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By listening for the rumble
of churning air,

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the pelicans can fly towards the thermal.

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(Rumbling)

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0nce they reach the base,
they rise in the updraught.

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The thermal may spiral them
3,000 metres above the ground.

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At the top, they peel off and glide
away to catch their next free ride.

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Like this, they float on air
from Europe to Africa.

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(Snorting)

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Elephants were the first land creatures

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known to have the power
to generate infrasound.

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(Grunting)

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Their secret rumbles
carry ten kilometres or more

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and act as a rallying call.

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(Rumbling grunts )

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The sounds are also used as
greetings and for other social calls.

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(Grunting)

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Since this landmark discovery,
other animals have been found

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that make sounds
beyond our perception.

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Hippos are now known
to use infrasound too.

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They also have a whole private
repertoire of other calls.

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(Grunting and rumbling)

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Even though these sounds
lie within our auditory range,

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the water surface acts as a barrier,
preventing us ever hearing them.

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The male uses these private calls
to communicate with the female.

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(Clicking)

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Advances that are not always welcome.

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(Grunting)

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The bellow we hear
is expelled through the nostrils

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and contains infrasound.

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(Grunting)

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The call also radiates underwater
and is picked up by the jaw.

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In air, infrasound carries five kilometres.

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It´s picked up by the ear.

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Both sounds leave together,

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but in water,
sound travels five times faster.

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In air, it lags behind.

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Hippos are thought
to exploit this time lag

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to judge how close a rival may be.

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They can hear underwater
infrasound 30 kilometres away.

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When they finally meet,
the outcome can be spectacular.

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As well as hippos, many other
animals are now known to share

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the sonic power that was
first discovered in elephants.

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Rhinos warn their offspring of
danger with these infrasounds too.

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(Grunting)

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(Rumbling)

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(Growling)

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Another extrasensory power in
elephants has been discovered.

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It lies in their feet.

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(Trumpeting)

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When threatened, they resort
to seismic communication.

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These shock waves carry to herds
50 kilometres away,

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alerting them to the threat.

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The tremors travel up the leg and
are transmitted to the inner ear.

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But sometimes
an elephant´s power deserts him.

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(Trumpeting)

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No animal uses extrasensory
sound more effectively

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than the dolphin.

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Many of its calls are pitched
far above our hearing range.

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Like a ship´s sonar,
it sends out these ultrasounds

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and creates a picture
from the returning echoes.

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(Clicking)

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Its forehead focuses the sound into a beam.

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Used like a sonic torch, it scans for prey.

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To gather more information,
it ups the pulse rate,

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penetrating its prey like an X-ray.

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There are reports of shipwreck
victims attracting dolphins.

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Their sonar penetrates us too,

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making our skeletons and lungs visible.

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As mammals,
we must appear similar to them.

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00:26:02,927 --> 00:26:06,602
Dolphins find pregnant woman
particularly fascinating.

251
00:26:06,727 --> 00:26:09,764
Its sonar acts like an ultrasound scan.

252
00:26:09,807 --> 00:26:12,196
(Heart beats )

253
00:26:13,967 --> 00:26:16,686
It even hears the embryo´s heartbeat.

254
00:26:17,767 --> 00:26:21,043
Perhaps they recognise
similarities here, too.

255
00:26:22,727 --> 00:26:26,640
Sharks feature in another dolphin story.

256
00:26:40,287 --> 00:26:42,243
When people are in trouble,

257
00:26:42,287 --> 00:26:46,439
dolphins are supposed to ward off sharks.

258
00:26:50,647 --> 00:26:53,639
They repel with high-speed blows.

259
00:26:54,967 --> 00:26:58,516
Stories also tell of them
saving people from drowning,

260
00:26:58,567 --> 00:27:03,163
bringing them to the surface,
as though aware of the danger.

261
00:27:12,327 --> 00:27:15,125
Some believe there´s
a special bond between us.

262
00:27:15,167 --> 00:27:17,317
Science is more rational.

263
00:27:18,407 --> 00:27:21,205
Dolphins support their own injured
at the surface,

264
00:27:21,247 --> 00:27:23,044
for they too can drown.

265
00:27:23,087 --> 00:27:26,762
Perhaps our struggles
trigger this behaviour.

266
00:27:37,767 --> 00:27:42,363
Alternatively, we may simply be
a novel plaything for them.

267
00:27:51,527 --> 00:27:54,883
Whatever the truth,
the known extrasensory powers

268
00:27:54,927 --> 00:27:56,918
of these incredible creatures

269
00:27:56,967 --> 00:28:00,164
are as remarkable
as any myths or legends.

270
00:28:08,007 --> 00:28:12,205
Extra senses are only one kind
of supernatural power.

271
00:28:12,247 --> 00:28:14,636
There are many others.

272
00:28:17,327 --> 00:28:19,397
0ur next supernatural journey

273
00:28:19,447 --> 00:28:24,077
will explore animal powers
at the outer limits of endurance.