All language subtitles for David.Attenboroughs.Natural.Curiosities.Series.3.5of6.Curious.Cures.720p.HDTV.x264.AAC.MVGroup.org

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The natural world is
full of extraordinary

animals, with amazing
life histories.

Yet, certain stories are
more intriguing than most.

The mysteries of a
butterfly's life cycle,

or the strange biology
of the Emperor penguin.

Some of these creatures
were surrounded by myth

and misunderstandings,
for a very long time.

And some, have only recently
revealed their secrets.

These are the animals, that
stand out from the crowd,

The curiosities, I find
particularly fascinating.

Some animals have intriguing
ways, of protecting their skin.

The hippopotamus lives
in Africa under the hot

tropical sun, yet
doesn't get sunburned.

And Capuchin monkeys live
in insect infested jungles,

but hardly ever get bitten.

How do these animals beat the
elements, and protect themselves

from sun, parasites and disease?

Hippos are large land mammals,
that can weigh up to 3 tonnes.

And they need to keep their huge bodies
cool, and protected from the sun.

To avoid the heat, they spend
much of the day swimming,

as they are doing now,
in the waters behind me.

But when they're
on land,strangely,

they don't appear
to get sunburned.

The secret of their sun tolerance,
lies within their skin.

It can sometimes appear
shiny and greasy.

It has unique properties, that
shocked the early explorers,

and now excites
modern scientists.

Hippos live in Africa,
south of the Sahara,

where temperatures can reach
40 degrees centigrade

But they spend much of the day,
submerged in rivers, lakes and swamps,

and so avoid the worst
of the sun's rays.

They possess formidable teeth, but
they are in fact herbivores,

and eat mostly grass,
great quantities of it.

And they graze mostly at night.

Even so, continually moving
in and out of water,

together with being roasted,
by the rays of the sun,

could be very damaging
to their skin.

But curiously, hippos remain healthy.

Throughout history,
the hippopotamus has

been the subject of
many strange tales.

The Greeks claimed,
they sweated blood.

And the Romans said, they
deliberately pierced

their skin on sharp
rushes, to release blood.

It seems bizarre, that an animal
would make itself bleed on purpose.

In the 19th century, one
special hippopotamus

allowed people to
get a closer look

at these strange
skin secretions.

In 1849, the British
Consul for Egypt,

Charles Augustus Murray,
formally requested

that the Pasha of Egypt,
helped capture a hippo,

for the Zoological
Society of London.

Hunters searched the reeds, on a
remote island called Obaysch,

2,000 km up the Nile, from Cairo.

They discovered a male hippo,
that was only a few days old.

When they tried to grab it,
a strange thing happened.

Murray describes how
a slimy exudation,

lavishly poured forth, from the

innumerable pores in the skin,

rendering it so slippery,

that the animal was
impossible to hold.

The hunters dropped
the baby hippo

back into the
waters of the Nile,

but they managed to
retrieve it again,

using the hook of a spear.

The prize hippo was
named Obaysch,

after the island of its capture.

And here he is.

Before his capture, young
Obaysch lived with his mother.

She had moved away from the
herd, to give birth alone,

and she protected him,
from lions and crocodiles.

Whether Obaysch became
accidentally separated

from his mother,
we'll never know.

But we do know, that
secretions from his skin

made him so slippery,

that he very
nearly escaped capture.

At this time, very little
was known about hippos,

and many people believed, that
they were some kind of horse,

that had taken, to
living in rivers.

In the early 20th century,
naturalists decided,

that they were closely
related to pigs.

DNA evidence however, now shows,

that in fact their
ancestors were cetaceans,

the group that contains
whales and dolphins.

So, hippos still retain many
adaptations, for a life in water.

Hippos are very heavy animals,
but for most of their time,

their bodies are
supported by water.

They're not really
very good swimmers.

In the water, they move by
bounding across the bottom.

They're well adapted to
a semi-aquatic life,

because their ears,
their eyes and their

nostrils are all towards
the top of the head,

which enables them to lie
almost totally submerged,

and yet still keep notice,
of what's going on, on land.

But their skin, is almost
entirely hairless.

So, on land it has
to be kept moist.

In order to prevent young Obaysch,
from sunburn and drying out,

the Egyptian Pasha had a boat
built, with a bathing pool,

to transport Obaysch in comfort,

all the way down the river Nile.

Accompanied by several cows,
to supply him with milk,

he arrived safely in
Cairo, 4 months later

On receiving Obaysch, the
British consul wrote excitedly

to the Zoological
Society of London,

confirming that the
hippo was alive,

and as tame and
playful as a puppy.

But his travels
were not yet over.

In the spring of 1850, Obaysch
was taken to Alexandria,

to board a P&O steamship,
called the Ripon.

A special hippo house with a
water tank, was built on the deck,

and in May, Obaysch arrived
safely in Southampton.

With the help of block
and tackle, he was

loaded onto a train,
bound for London.

And at 10 o'clock at
night, the tired hippo

and his keeper,
reached London Zoo.

His home was a newly
constructed enclosure,

complete with a
heated swimming pool.

After many hours of traveling,

the hippo gratefully
plunged into the water.

Obaysch, the hippo
sensation, had arrived.

A journey of over 5,000
miles, by sailboat,

steamboat, and a train
brought a hippo to England.

The first one,
since Roman times.

Now Europeans had
a chance to get

close to this unusual creature,

and perhaps learn more, about

it's strange skin secretions.

Later, more hippos
arrived at other zoos,

and the blood-red
sweat was seen again.

In the cooler climate of Europe,

hippos don't sweat very much.

But zoo-keepers have reported,

that sometimes in the morning,

they see red trickles forming

on the flanks or these animals.

It comes from
particularly large pores,

which form streaks on
the animal's side,

which does look,
a little like blood.

We know for some time,
that this is a moisturizer.

But why it's red, has only
just been discovered.

A little more.

Come on.

There we go.

Recently, Japanese
scientists were intrigued

to see photos of a
wild baby hippo,

with light-pink skin,
that still didn't burn

under the harsh African sun.

They wondered, if
the red secretion

played a role, in
protecting its pale skin.

So they collected
hippo secretion,

from captive hippos, to
look at its composition.

They discovered two pigments.

A red one, that they
named Hipposudoric Acid,

and an orange one, that they
called Norhipposudoric Acid.

The red pigment was
found to absorb

harmful wavelengths of light,

and both pigments
were anti-bacterial.

Here was the answer, to why
hippos never got sunburned.

And why the wounds
of battling males,

rarely became infected.

The mysterious slime, is
neither blood, nor sweat,

but a specialized secretion,
that turns red in sunlight,

and protects the hippo's skin.

So, what became of Obaysch,

the first ever hippo
in captivity,

that gave us a close-up view,
of these curious creatures?

For several years, he was the
sensation of London Zoo.

He even inspired the Hippo Polka,
a popular dance at its time.

But visitors grew weary of him.

Some were disappointed, not
to see a giant river horse.

And others expected a ferocious
beast, not a gentle giant.

Obaysch died in 1878,
at the age of 28.

And he and others that followed,

taught us some intriguing
things about hippos,

including the reason for
the blood-red droplets,

found on their skin.

So, hippos can produce
their very own

natural suncream,
which is waterproof,

moisturizing, and
anti-bacterial.

Next, meet another animal, that
also has its own curious cure.

The Capuchin monkey, that
deals with biting insects

in a particularly
intriguing way.

The hippo produces a
natural suncream,

to prevent its skin
from getting burned.

Capuchin monkeys also need
to protect their skin,

and do so, in a very
surprising way.

When early explorers reached the
Americas in the 15th century,

they encountered small
monkeys, with patches of

dark-brown fur on their
heads, that resembled hoods.

So they named them after a
group of Franciscan friars,

called Capuchin monks.

Capuchin monkeys, quickly charmed
their way into our hearts.

With dextrous hands, and
inquisitive personalities,

they seemed very human-like.

They were also adept,
at learning tricks.

And soon became popular
performers, on our streets.

In the past, we used
to teach monkeys,

how to do things,
how to perform tricks.

But things are different today.

Today, monkeys are
teaching us things.

Watch what happens,
when I give them

a few spring onions,

and some chili peppers.

They're clearly not eating,
what I offered them.

They're rubbing themselves, with
the peppers and the onions.

You might think they're nuts,
because they're captive monkeys,

and they are just doing that,
to entertain themselves.

But not so.

I've seen capuchins do
just that, in the wild.

These white-faced
capuchins in Costa Rica,

reacted in much the
same way, when they

came across a particular
rainforest plant,

the Piper plant.

These leaves have a
distinctive liquorice scent,

and they're hard to come by.

So, when they do find
them, the monkeys

pass the leaves
among the troupe,

so that everyone
could have a share.

Both in the wild,
and in captivity

Capuchin monkeys become
similarly excited,

at the sight of lemons or limes.

And again, the same
frenzied activity,

and fur rubbing follows.

What is it about these plants,

that gets the
monkeys so excited?

We know, they all give
off a pungent smell,

so could this be, what
the capuchins are after?

Smell plays an important part

in the lives of many primates,

but none more so,
than in the lives

of these lovely
ring-tailed lemurs.

They use it,

both, to establish their
position within the troupe,

and also the boundaries, the
frontiers of their territory.

If you look at the inside
of their forearms,

there's a black
patch, without fur.

And there, the skin is loaded
with glands, that produce

a very strong smell.

And when these boys go into battle..
oops!

When they go into battle,

they draw their furry
tail to their forearms,

loading it, with scent
from those glands,

and then, they wave
it over their backs,

in the direction
of their enemies.

In a kind of stink fight.

You understand that, don’t you?

Oh!

The pungent scent is also used

by males, during
the mating season.

This male, has rubbed his own
distinctive smell onto his tail,

and he now wafts it towards a female,

to signal his intentions.

But she is not
entirely convinced.

Unlike lemurs, capuchins
don't have scent glands.

So, some thought, that
they could be using

the smell of certain plants,
for communication.

But it turns out, that they have

a different perfume
for that job.

Urine.

Which they apply
lavishly to their fur.

So why then, do they also anoint

themselves with other smells?

The answer may be found,
in our own history.

The early Romans, noticed
some 2,000 years ago,

that the fruits and leaves
of the lemon plant,

have an exceptionally
strong scent,

that can be used to
ward off insects.

A further clue, as to
why capuchins might

cover themselves, in
such pungent smells,

comes from this plant.
The piper plant.

Throughout the Amazon,
Indian tribes apply it

as an antiseptic on wounds.

And in Costa Rica, it's used
as an insect repellent.

Could it be, that Capuchin
monkeys protect themselves,

against the onslaught
of mosquitoes

in much the same
way as humans do,

by rubbing themselves,
with mosquito repellent?

In 1993, scientists
at Oxford University,

decided to put the
question to the test.

They collected some feather lice,

and put them into Petri
dishes overnight.

Into one dish, they also
placed a slice of lime.

The next day, the lice, without
the lime, were mostly alive.

Whilst in the other dish,
two thirds had died,

and the remainder
were paralyzed.

Clearly, the lime contains
a lethal insecticide.

Today, we know, that
citrus fruit peel

does indeed contain
insecticides,

which disrupts the nervous
system of many small insects,

causing them to become
uncoordinated and paralyzed.

The leaves of the piper
plant, are antiseptic,

and contain substances,
to protect against

fungal and bacterial infection.

And chili pepper extract, is commonly
used in households and gardens,

to deter small mammals
and insect pests.

So it seems, that the
clever monkeys know exactly,

how to make the best use
of nature's remedies.

Recent researchers also
revealed, that capuchins

anoint themselves far more
during the wet season,

When mosquitoes are
more abundant,

and the risk of
infection is higher.

Troupes use different
plants, possibly, simply

because they have to use,
what's locally available.

But there's one substance with
insect repellent qualities,

that appeals to primates,
including capuchins,

that comes, not from a
plant, but from an animal.

An animal...

..like this.

A giant millipede.

When attacked, or in danger,
tropical millipedes

often produce a powerful,
defensive secretion.

And black lemurs
have worked out,

how to use this to
their advantage.

When they find a millipede, they
give it a gentle bite to the head,

to make it release its secretion, and
then rub this through their fur.

The toxic fluid has a strong
smell, and is highly irritating.

But it protects the lemurs
against mosquitoes.

This pungent secretion, has
apparently another strange effect.

It seems to act as a narcotic, sending
the lemur into a kind of trance.

Like other drugs, it has
powerful side effects.

We still don't understand
how capuchins and lemurs

select the plants, that they
use for medicinal purposes.

These capuchins behind me, were
born and raised in captivity,

so they never
encountered the plants,

that their parents and
ancestors would have used.

So, how do the monkeys know,
which plants to choose?

Can they detect particular
substances in them?

Or is it something,
they learn from others?

We don't yet know the
answers, but it could be that

babies learn by
watching the adults,

and that it's passed
down the family line.

It's clearly a great, social
event with everyone joining in.

And afterwards, the entire group
appears to be more tightly bonded.

When Europeans first saw
monkeys in the wild,

they thought, that they
were imitating, what

people did, in some
of their behaviours.

But quite the reverse.

It now turns out, that
many of the local people

did things that the
monkeys had taught them.

Using plants as medicines.

So it seems, clever monkeys
have taught us a trick or two.

So it's clear, that we
are not alone in using

medicines against
injuries and infections.

Both Capuchin monkeys
and hippos, discovered

some medical remedies
long before we did.

***