♪
narrator: Animals...
Do the most incredible things.
[ goat bleats ]
like this...
And that.
I bet you're wondering, "how do they do that?"
we're revealing animals' biggest secrets, like...
Do elephants really never forget?
Can dogs detect diseases that doctors may miss?
And why does this amazing animal have blue blood?
These wonders and more on...
-- Captions by vitac -- www.Vitac.Com
captions paid for by discovery communications
it's 2:00 a.M. In bedfordshire, England.
A very special dog called magic has woken up.
[ whines ]
somehow, magic knows his owner claire's blood-sugar levels
haven fallen dangerously low.
[ whines ]
claire is a diabetic,
and right now, if she doesn't wake up and take her meds,
she could slip into a coma.
[ whining ]
♪
claire: He saved my life over four-and-a-half-thousand times.
He's my guardian angel,
and without him, I wouldn't be alive today.
[ dog barks ]
[ panting ]
narrator: In the last 10 years,
tests have shown that dogs can sense cancer.
Now, at the uk's medical detection dog research center,
scientists are hoping to harness the dog's superpower
to diagnose an increasing number of human illnesses.
Freya is the latest recruit.
She's being trained to detect the world's
most deadly disease -- malaria.
The malaria parasite kills a million people every year
by infecting the person's bloodstream.
The parasite attracts mosquitos to the person its infecting
by making the victim produce
a sweet-smelling chemical through their skin.
Although too faint for us to smell,
the sweet scene is irresistible to mosquitos,
who then drink the parasitic blood
and carry the parasite off to the mosquito's next victim.
But this sweet-smelling odor could be malaria's downfall
because if freya can smell the infected blood,
then doctors could potentially quarantine people
carrying the parasite before it has the chance to spread.
The stakes couldn't be higher.
Freya's trainer, mark, has four pairs of well-worn socks.
One of them is from a person infected with malaria.
We get socks sent to us where we don't know who has
and who hasn't got malaria.
These were worn for 24 hours.
We use that to train dogs to recognize the odor,
and then the dogs identify intestine conditions.
Narrator: One of the pairs of socks belongs to a child
who has malaria at such an early stage
the disease hasn't yet become infectious.
The team is hoping freya's incredible nose will be able
to detect the tiny quantities of the parasite's sweet smell
produced in this super-early phase.
Like all dogs,
freya has 300 million smell receptors in her nose,
50 times more than in humans.
And the area of freya's brain
that processes the information from her smell receptors
is 40 times larger than ours.
This combination of smell receptors and processing power
gives freya the ability to detect tiny scent particles
in the air far beyond anything we can.
Mark: You ready? Seek, seek.
Narrator: But is her nose good enough
to potentially save millions of lives?
If freya detects the malaria smell, she will sit down.
♪
good girl.
Narrator: This smelly sock test is an important step
in beating the world's most deadly disease.
Freya is just one of 130 pooch pioneers.
They're among the first generation
of bug-hunting bloodhounds
learning to use their incredible noses
to identify everything from prostate cancer
and parkinson's disease to seizures and narcolepsy.
Some of these dogs are already sniffing out trouble
and saving lives,
which brings us back to diabetes-sniffing magic.
He lets me know when my blood sugars
are becoming dangerously low.
Narrator: It's like claire's got her very own
dog-tor. [doctor]
[ zebra vocalizes ]
at the bottom of the ocean is a lifeform like no other.
It's got eight limps, 2,000 suckers,
the gift of invisibility, and nine brains.
You might be forgiven for thinking these guys
come from another planet,
because the weirdness goes even deeper,
right into the octopus' blood.
Octopuses are the jet-setters of the ocean,
because they breathe in water and squirt
it out of their siphon to achieve jet-like acceleration.
But jetting around gets exhausting.
So, most of the time, the octopuses prefer
to take a leisurely stroll along the seabed.
But by being forced to stick close to the ocean floor,
the octopus finds itself walking into
some of the most extreme environments on the planet.
From the broiling 130-degree waters
around the indian ocean's hydrothermal vents,
to the staggering depths of the pacific,
where at 13,000 feet below the surface,
you'll find the aptly named dumbo octopus.
Down here, the weight of sea pushing down from above
creates a pressure that would crush a human
like a steamroller rolling over a soda can.
Even if a human could survive, it's so cold,
it would be almost impossible for our blood
to get oxygen around the body.
In humans, red blood cells carry the oxygen.
The cells are red because they contain iron.
The iron reacts with oxygen to create crimson-iron oxide,
most commonly known as rust.
Yes, our blood is literally rusty.
But a quarter of a mile down, iron struggles to carry oxygen
under the extreme pressures and temperatures.
So, instead of iron, the octopus uses copper,
and when copper reacts with oxygen in the body,
it turns blue.
Copper is far more efficient at carrying oxygen in the cold.
Thanks to their blue blood,
octopuses can thrive even in near-frozen depths,
where levels of oxygen are less than 0.1%
of what we have on the surface.
That's oxygen levels similar to those at the edge of space.
In these alien worlds,
squid,
cuttlefish,
and horseshoe crabs
all have copper running through their veins.
But don't worry, the bluebloods aren't likely to take
over the planet,
because scientists have discovered blue blood
has a downside.
The cooper oxide makes an octopus' blood thick,
and that makes it incredibly hard to pump around the body,
which is why the octopus has to rely on not one,
but three hearts, and with three hearts weighing them down,
the octopus will find it difficult to walk
anywhere other than the ocean floor,
even if they have got eight legs.
[ ribbitting ]
coming up, the architectural masterpieces animals call home,
and how does one of the world's tiniest animals
create one of its biggest noises?
Narrator: Home, sweet home.
Some animals take nest-building to the next level,
building dream pads
that are nothing short of architectural marvels.
But...
Crowded, heavy traffic.
[ monkey calling ] noisy neighbors.
In the world's bustling rainforests,
orangutans love nothing more than to head home
for a good sleep.
Problem is, last night's pad could be miles away.
So, an orangutan is forced to build a new nest
almost every night.
A dizzying 65 feet up,
the orangutan finds a thick branch
that will support his 300 pounds of weight.
Then he snaps off sturdy branches to form a frame.
And with an ingenious bit of ape engineering,
he knits it all together with thinner, bendable branches.
They may be the biggest tree-dwelling animal
to make a nest, but orangutans don't make the biggest nest.
[ chirping ]
over in the kalahari desert in southern africa,
a little critter takes that title.
The sociable weaver's colossal constructions
are up to 20 feet wide,
and each house houses up to 100 families.
That's a whole village of home-birds on one tree.
Although the biggest single nest in the animal kingdom,
it has nowhere near the largest population.
On the sun-scorched plains of northern australia,
these 13-foot towering structures
look like neolithic monuments, but they are actually home
to between one and two million magnetic termites.
Inside are thousands of dedicated floors.
The bottom floor houses the king and queen,
and at the top, there's even a cemetery
where the termites bury their dead.
You would think these nests turn into ovens
in this 100-degree sun,
but these termites are hvac experts.
Inside each nest is an air-conditioning unit
so ingenious it's inspiring modern skyscraper design.
As all the termites breathe in and out,
water vapor condenses on the walls
and slowly drips down to the basement,
creating a cold, wet floor.
As the cool water evaporates in the heat,
it's drawn toward a chimney at the top,
cooling all floors of the skyscraper as it rises.
It's like a giant refrigerator.
Magnetic termites are nature's
structural engineering masterminds,
able to deliver cutting-edge, eco-friendly climate control.
But no elevator.
[ growls ]
coming up, how good is an elephant's memory?
And how do tiny cicadas
make one of the biggest rackets on the planet?
Narrator: The elephant, the biggest land animal on the planet.
In the wild, they can live for 80 years.
That means there are elephants alive today
who lived through the second world war.
[ calls ]
and thanks to their enormous brain,
some people believe these elderly elephants
can remember it all.
Since the 1970s, scientists have known that elephants
remember things that are vital for their survival,
like the locations of water holes or food sources.
But what sets elephants apart from almost all animals
is that they also store memories not linked to their survival.
So, if a piece of information isn't vital,
how long can an elephant remember it?
At the adventures with elephants sanctuary in south africa,
scientists and rangers have been trying to unlock
the secrets of the elephant's memory.
Hug? Good boy.
Well done.
This is 3-year-old female musina.
Keeper: She is a fantastic elephant.
Absolutely a born leader.
Narrator: Today, musina's keeper has devised
a short-term memory test.
-Your name, ma'am? -Elsa.
Necessary he's introducing musina to three visitors.
-Your name, ma'am? -Lori.
Narrator: The keeper shouts each person's name.
-Your name? -Kyle.
Narrator: And musina takes a look.
Will musina remember something as unimportant to her as a name
and recall it in an hour?
Okay.
One hour later, the visitors return to test musina's memory.
If you could swap your positions,
just to mix up, to confuse the elephant.
Thank you.
The visitors have changed where they're standing.
So, will musina be able to tell them apart
and remember their names?
And in a few...
The ranger tosses his cap on the ground and asks musina
to pass it to the person whose name he calls out.
Now, give it to kyle.
Where's kyle?
-Ohhh. -Nicely done.
Keeper: Give it to elsa.
Give it to elsa.
Oh, beautiful!
Keeper: Give it to lori.
Where's lori? -Yes. Aww.
Narrator: A study revealed on average,
animals tend to forget information
after just 27 seconds,
unless it's vital to their survival.
That makes musina's ability to remember a name
and a face after an hour remarkable.
What about an elephant's longer-term memory?
Scientists at munster zoo in germany tested another elephant
by showing her 26 shapes printed on cards.
Amazingly, a year later, induced by tasty treats,
she was able to remember all of them.
Why elephants are able to recall short-
and long-term information not linked to survival
may be connected to an area of an elephant's brain
called the hippocampus, which is linked to emotion.
This part of the brain encodes
emotional experiences into memories.
It may be that, like humans,
elephants remember things for an especially long time
when it has a great emotional impact on them.
When elephants form an emotional bond,
they recognize each other,
even after being separated for decades.
Elephants are also the only non-human animal
to mourn their dead over long period,
even returning to visit graves.
So, it seems like there is some truth behind the myth
that elephants never forget.
Coming up, how can one tiny bug sing loud enough
to make you deaf?
♪
narrator: For 17 years, the cicada is silent.
And then in the last month of their life...
[ rattle-like sound ]
these two-inch critters produce a call so loud,
it rivals a jet engine at takeoff,
and continued exposure can even lead to deafness in humans.
There are around 3,000 species of cicada worldwide.
Despite their small size, cicadas have been recorded
producing a 120-decibels call,
making them the loudest insect on earth.
But mysteriously, they spend up to 17 years silent as wingless,
juvenile bugs living underground.
Nobody knows exactly why they stay there so long.
When the grubs finally rise to the surface,
they climb a tree and molt.
And they emerge, for one month only,
as a fully formed and fully winged cicada,
each ready to sing a song that, at 120 decibels...
Is as loud as a rock concert.
The incredible volume comes not from the bug's wings,
but from its body,
which is actually built just like an acoustic guitar.
Inside their hollow abdomen,
cicadas have two organs called tymbals.
These wafer-thin membranes are lined with ribs,
each as thin as a human hair.
These are the cicada's guitar strings.
Muscles contract, buckling the tymbal's ribs,
causing it to make a short, sharp noise.
And when the tymbal snaps back, [ click ]
it produces another sharp click. [ click ]
so, what sounds like a single, ear-splitting buzz
is actually 400 ear-splitting cracks every second.
It's the male cicadas making all this infernal noise,
and they do it because they think it will impress the girls.
And sure enough, the girls come running.
As for which of these eardrum-busting bugs
have the most luck in the love department,
sadly, it's the same old story --
females seem to be attracted to the loudest males.
So, the proud, loud fathers have noisy kids,
and the merry-go-round of mayhem continues.
Where's the volume button?
[ guitar chord strums ]